Behavior-related changes in dopamine and ascorbate release
FSCV is an important tool that will be used to study the role DA might play in weakening association between a CS and a US. Classic theories of DA state that DA is associated with pleasure, acting as a natural reward system. However, further studies have questioned the classic model, indicating that DA is actually associated with anticipation of a reward. To study this, we inserted an electrode into the striatal region of the brain that is capable of measuring extracellular DA concentrations. After conditioning the rat to respond to an unconditioned stimulus (US) using classic Pavlovian methods, we measured DA release during the conditioned stimulus (CS) and during the US. We are also interested in seeing whether food presented will reinstate DA signal to the CS in extinction after behavioral performance reaches zero. Therefore, after extinction, we reinserted the electrode and measured DA concentrations during the CS and US again. Unfortunately, we were unable to replicate the experiment perfectly due to complications with the lab animals. The rats responded to the CS during the 1st 4 days as shown in Figure A. However, when the electrode was put in place, the rats stopped responding to the CS. Our previous results do show DA mediated association between CS and the US, and that food presentation does reinstate DA signal after extinction.
Ascorbate (AA) is an antioxidant vitamin which is released into the striatum of the brain during behavioral activation. A mouse model of Huntington’s disease has 140 CAG repeats knocked into the Huntington’s gene. These knock in (KI) mice show a deficit in extracellular AA. Furthermore, deficits in AA are known to impair motor response. In order to study this deficit, we used slow scan voltammetry to measure extracellular AA concentrations in KI mice. KI mice appear to have deficits in both AA release and associated behaviors. We evaluated the cause of this deficit by treating the KI mice with d-amphetamine sulfate (5mg/kg sc). This drug promotes corticostriatal glutamate transport, resulting in increased striatal AA release, and uptake in extracellular glutamate. Compared to wild type (WT) mice, KI mice have lower striatal AA after treatment with d-amphetamine sulfate, indicating that alterations in corticostriatal glutamate transmission may contribute to the AA deficit in Huntington’s KI mice. This difference is even more noticeable in male KI mice, indicating a possible gender role in the progression of the disease.

REU Mentors:  George Rebec, Department of Psychological and Brain Sciences

Investigations of learning and memory in an animal model of autism
Autism spectrum disorder is a neurodevelopment disorder that affects speech, communication, behavior, and social cognition (Behrmann et al). Although there are animal models for the disorder, none of them has investigated the behavioral aspect of the disease within the neurological context. Injections with the anticonvulsant compound valproic acid (VPA) intraperitoneally at 600mg/kg on embryonic day 12.5 in pregnant dams induce autistic like features in the pups. The aim of this study is to investigate this animal model for autism in several behavioral tasks with the long-term goal of comparing any possible behavioral deficits with those reported in humans with autism. The tasks employed here included: 1) eye blink- conditioning (a Pavlovian conditioning task), and 2) the Morris water maze (MWM, a spatial memory task), and 3) a delayed match to place (DMP, a spatial working memory task in which the escape platform location is changed daily) with or without prior training in the Morris water maze. “Autistic” rats were trained to perform these paradigms and then compared to saline controls. In the eye blink-conditioning task the animals were trained with an optimal 200 msec ISI, followed by training with a non-optimal 600 msec ISI. We find higher amplitude CRs in the autistic rats, and shorter CR latencies with the longer ISI.
In the MWM task, VPA rats showed a slowed acquisition of the escape response. In the DMP task, the autistic rats showed no working memory deficit whether the animals received prior training in the MWM task or not. Autistic rats did show impairments in Trial 1 performance in the DMP task relative to controls early in training, but only when they were not initially trained in the MWM task, suggesting impairment in the development of an efficient search strategy for the novel platform location. These results suggest that this model of autism may be a valid one as the behavioral deficits found can, at least in part, be attributed to brain anomalies shared with autistic humans.
REU Mentor:   Preston Garraghty, Department of Psychological and Brain Sciences

The effects of light intensity on motion perception in the Eastern Fence Lizard, (Sceloporus undulatus) and Southern Sagebrush Lizard, (Sceloporus graciosus).
Motion detection is utilized in prey, predator, and mate detection as well as communication. Environmental conditions, such as light intensity, habitat structure, and spectral quality, are likely to have a great effect on an animal’s ability to detect various signals. We examined how total light intensity affects motion perception in diurnal lizards from the genus Sceloporus (S. undulatus and S. graciosus). We tested motion detection latency by recording optokinetic response times to two light intensity (10 Lx and 400 Lx) and two motion frequency treatments (1 Hz and 4 Hz). We found some evidence for differences between males of two populations of S. undulatus that correspond to major differences in their photic environments. Male Sceloporus undulatus cowlesi from White Sands, New Mexico were better able to detect motion at low light intensities whereas male Sceloporus undualtus consobrinus from the typical scrub habitat in the Chihuahuan Desert in New Mexico were better able to detect motion in bright light. Sex differences in motion detection corresponded better with previously-observed differences in the function of visual displays. Female S. graciosus were consistently better able to detect motion than were males. Because of small sample sizes, these differences were not statistically significant.
REU Mentors:  Emilia Martins and Saul Nava, Department of Biology

The reproductive behavioral displays of male Sceloporus towards females.
Male Sceloporus have been shown to choose among females in choice tests. Sceloporus females, on the other hand, do not have preferences but only reject when males are attempting to mate. In previous experiments, simultaneous choice tests have been done to show preference among Sceloporus with not much emphasis being put on the individuals’ behaviors. We compared behavioral tests to other methods of choice that have been used in the past in order to see how males might behave towards females in the wild and to see if any relationship exists between sequential and simultaneous tests. In the sequential behavioral tests, males were allowed to interact for forty minutes with one of two females, and then later tested with the second female. The behavioral displays were scored using an ethogram, and females were determined as either preferred or not preferred depending on the difference in displays exhibited towards each. Behavioral preferences were compared to female preferences in outside enclosure and indoor arena choice tests (both simultaneous), and the time at which the female laid eggs. Although results were not statistically significant, major trends were seen in the data. Males showed a random pattern of preference when comparing total simultaneous choice to the sequential choice. However, the simultaneous choice tests conducted indoors gave results that were very different from the sequential behavioral tests, whereas the simultaneous tests conducted in large outdoor enclosures gave results similar to the sequential tests.
REU Mentors:  Emilia Martins and Mayte Ruiz

Electrocommunication signal repertoire in Parapteronotus hasemani
Apteronotid electric fish species (Family Apteronotidae) communicate using frequency modulations of their electric organ discharge (EOD). Some species use this behavior to convey information regarding sex, body size, reproductive status and aggressive intent. The modulations are often sexually dimorphic and exist in several varieties. In Parapteronotus hasemani we aimed to test for the differences in chirping behavior between sexes and to inspect the signal repertoire. Due to size constraints it was not possible to sex all of the fish. However the chirp repertoire was described for this species. We used a playback of simulated EODs to examine the types of signals produced. The playback stimuli had frequency values of ±5, ±20, and ±150 Hz relative to the subject’s baseline EOD frequency. We compared production of each chirp if fish produced them in response to the stimulus. Four distinct kinds of signals in were measured: gradual frequency rises (GFR), rasps, long (duration) chirps, and short chirps. All of these differed in their structure and fell into separate clusters on a scatter plot of frequency modulation vs. time. Fish produced fewer GFRs in response to presence of a stimulus at all playback frequencies. They also showed a decrease in rasp proportion as a response to different stimulus frequencies. Fish increased long chirp rate in response to playback frequencies closer to their own. Conversely, fish produced more short chirps to stimuli furthest from their own baseline EOD. Additionally it was found that overall chirp duration was positively correlated with each subject’s baseline EOD frequency. Understanding the structure of these different responses in P. hasemani will allow us to compare them with other apteronotid species.
REU Mentors:  Troy Smith and Cameron Turner, Department of Biology

Possible influences of positive scent stimuli on the behavior of captive polar bears (Ursus maritimus).
Predatory animals in captivity often exhibit stereotypic behaviors, such as pacing, which are repetitive and seemingly pointless. One theory is that these stereotypic behaviors are used as a replacement for species typical behaviors that the animals may exhibit in the wild, for example, pacing may be a substitute for traveling long distances to find food. Previous studies have shown that environmental enrichment in certain zoo animals may help to decrease these stereotypic behaviors. This study will attempt to use environmental enrichment on two captive polar bears (Ursus maritimus), one female and one male, to encourage behavior more closely related to natural foraging. Previous studies have presented animals with a single food enrichment item, but the effects on the animal only last as long as the food available to the animal lasts. By presenting the animals with a stimulus on a fixed interval schedule, such as the beef and fish scent stimulus presented every minute, the animals may be encouraged to search for food around their exhibit and decrease their stereotypic behaviors. They will be monitored five days a week for an hour and half total each day: a half hour before, during, and after the presentation of the scent stimulus. There were five days of baseline observation where no spray bottle was present, five days of scent stimulus, five days of baseline with a water spray bottle, and the last five days were scent stimulus days. The presentation of the spray was always in the same area in the visitor viewing area of the polar bear exhibit area. The animals will not be able to consume food at that time, but the smell of food may help to decrease their stereotypic behaviors and increase recognizable focal foraging behaviors, since the bears can smell odors from far distances. Both polar bears seemed to respond to the scent stimulus by smelling the air during the spray period of observation, but the amount of time spent performing non-stereotypic and stereotypic behaviors appeared to vary from day to day independent of scent stimulus. Data and further results are in the process of being analyzed.
REU Mentors:  Bill Timberlake and Eddie Fernandez, Department of Psychological and Brain Sciences

Seasonal changes in immunity track changes in energetics and not reproduction in female Siberian hamsters (Phodopus sungorus).
Non-tropical organisms must deal with marked seasonal fluctuations in their environments. Photoperiod is the primary environmental signal organisms use to predict such changes. In order to maintain a positive energy balance year-round, a variety of physiological and behavioral adaptations have evolved, including seasonal changes in reproduction and immunity. Exposure to short day (SD) lengths (i.e., “winter”) inhibits reproductive activity and triggers gonadal regression and decreased body mass. The physiological signal that transduces photoperiod is the pineal hormone melatonin, which is secreted only during the duration of dark hours, thus encoding the amount of light. The goal of this study was to determine the effects of melatonin on glucoprivation-mediated changes in immune function in Siberian hamsters. Specifically, daily timed injections of melatonin or saline were given to induce SD-like conditions; a subset of hamsters from each group received multiple injections of 2-deoxy-D-glucose (2-DG), a glucose analog, to induce a state of glucoprivation. Immune responses were quantified by measuring anti keyhole limpet hemocyanin (KLH) antibodies and bacterial killing capacity. The results demonstrate that both melatonin and 2-DG inhibited antibody production compared to control animals. Specifically, animals within the SD-like melatonin treatment had lowered antibody production in response to 2-DG as compared with the control animals. Within the LD group there was no effect of 2-DG on antibody production. Furthermore, there was a trend towards increased bacterial killing ability with 2-DG in the SD-like treatment group compared to the other groups. There was no effect of melatonin or 2-DG on cortisol concentrations in any group. SD-like melatonin caused an overall decrease in specific fat pad masses and body weight, but there was no effect of melatonin on reproductive mass. Fat pad and body masses, but not reproductive mass, were also significantly positively correlated with immune function. These data suggest that the immune effects are likely to be driven by changes in resource availability (i.e., energy) rather than changes in reproduction. Collectively, these data provide support for the role of energetic trade-offs between competing physiological functions in mediating seasonal responses.
REU Mentors:  Greg Demas and Devin Zysling, Department of Biology

Odor preference in huddling by rat pups: Comparison between the metabolic consequences of huddling and the sensation of localized warmth as an inducer of odor-guided huddling.
During the first two postnatal weeks, rat pups huddle with warm objects, either animate or inanimate. Huddling with a warm object in a cooler environment reduces loss of body heat and conserves metabolic energy. By Postnatal Day (PD) 15, pups huddle preferentially with targets bearing species-typical odors. Nevertheless, the odors that elicit and maintain huddling contact can be reassigned by pairing that odor with the experience of the thermotactile component (warmth) of maternal care.
It is possible that the sensation of huddling with a localized source of heat constitutes the mechanism for establishing odor-guided huddling. Alternatively, the metabolic consequences of huddling may be sufficient to induce a specific odor-guided huddling preference. The present study was designed to compare the induction of huddling preferences derived from the metabolic consequences of huddling with those derived from the sensation of localized warmth. Two treatment groups were studied, with each group receiving two kinds of conditioning on alternate days, from PD 9 – 14. Pups in Treatment Group 1 were exposed for 2-hr/day on alternate days to a furry, warm (36°C) tube bearing a fixed amount of odor A (e.g., lemon), all in a cooler (23°c) compartment. On the other days, these pups were exposed to the same amount of odor B (e.g., orange) within a cool (23°C) ambience. Treatment Group 2 received the same regime of access to a scented warm tube in a cool ambience and, on alternate days, these pups were exposed to odor B in a warmer ambience (26°C) that had been shown to be metabolically equivalent to the warm tube condition. Results suggest no effect of treatment on odor preference in huddling. When the treatment variable was excluded from the analysis, however, a sex dependent effect of localized warmth on odor preference was found. . Female pups preferred to huddle with an odor associated with a warm tube compared to an odor associated with no tube; males had no odor bias in huddling.
This study suggests that the metabolic consequences of huddling facilitate development of odor-guided huddling on PDs 9-14. Nevertheless, it will be useful to extend the conditioning period and/or introduce the conditioning to pups that are younger. For future research, sex should be considered as a significant factor for establishment of odor-guided huddling. Neuroendocrinological studies could be helpful to explore mechanisms underlying development of filial huddling by rat pups.
REU Mentors:  Jeff Alberts and Sayuri Kojima, Department of Psychological and Brain Sciences

Repeatability in guppy inspection behavior, alone and in groups.
Guppies, Poecilia reticulata, in the wild "inspect" potential predators. The rate at which a guppy inspects is influenced by the historical predation level experienced by their population and interactions with social partners. It is not known how consistent an individual's behavior is in response to repeated interactions with a predator or how consistent an individual's behavior is in the context of its social group. We utilized a strain of guppies originating from a high predation population of the Quare River that has been in the lab for more than six generations. We tested focal individuals three times alone or twice in a group in the presence of a cichlid model to determine how repeatable individual behavior is alone and within a social group. Individuals were scored for time spent in agitated swimming, in close proximity of the model, foraging, frozen and oriented on the model and how often they inspected the model. Focal individuals tested alone appear to habituate to the model and therefore exhibit low repeatabilities for all measured behavior. Guppies are known to socially learn and are unlikely to interact with predators in the absence of conspecifics. Low repeatabilities are thus not surprising. The second experiment was therefore tailored to both minimize learning and reflect more realistic social settings, providing a more accurate measure of repeatability. The results of the second experiment show much higher repeatabilities for all behaviors. Guppy antipredator behavior is therefore more consistent across repeated encounters with predators in the context of their social groups, suggesting that social context may play a significant role in the evolution of guppy antipredator behaviors.
REU Mentors:  Butch Brodie and Heather Bleakley, Department of Biology

Cue competition and integration in a blocking procedure in the water maze as a function of beacon type and whether it was switched between Stage 1 and Stage 2 of training.
In a blocking procedure in the water maze, subjects are typically trained in Stage 1 to find an escape platform using a Beacon, and in Stage 2 to find the platform using a combination of Beacon and added Landmarks. Timberlake, Sinning, & Leffel. (2006), and male rats, found both cue competition and integration with the Room cues depending on the type of Beacon (Pole or Hanging) and form of training (with or against background cues) in Stage 1. Random Pole Beacons produced cue competition, and Fixed Hanging Beacons produced facilitation relative to a control receiving Stage 2 training only. The purpose of the present research was to determine if (1) cue competition also occurred with females receiving Random Background training with Pole Beacons but not Hanging Beacons; (2) the effects of changing the Beacon type between Stages 1 and 2 disrupted cue competition effects as predicted from Roberts & Pearce (1999) and (3) whether the direction of change mattered as might be assumed if the novel pole detracted from learning the Room cues in Stage 2.
REU Mentor:  Bill Timberlake, Department of Psychological and Brain Sciences

Effects of social environment on boldness behavior in laboratory and wild zebrafish
Many studies have demonstrated that behavior has both a heritable and environmental basis. Traits may be inherited or innate, socially influenced by watching others behave or affected by external factors, like stress. Studies have also shown that younger animals are more likely to acquire behaviors from older individuals, consequently making the stage of development at which they are exposed to social stimuli another important factor that can affect behavior. In this experiment I determined whether the social environment of individuals can have an effect on boldness in laboratory and wild zebrafish (Danio rerio). I created mixed strain groups and varied the stages of development at which laboratory and wild zebrafish were housed together. These groups included: mixed as eggs, mixed three weeks after hatching and mixed at 5 months of age. A pure tank of each strain was used as a control. Each group was assayed for shoaling tendency, activity level in an unfamiliar environment, predator avoidance and feeding latency after stress. The results from these tests demonstrate that there is a significant difference in boldness between wild and domesticated strains, with the domesticated strain being bolder. The domesticated strains displayed higher activity level, less predator avoidance, and lower feeding latency. It was also demonstrated that the social environment and stage of development in which that individual was exposed to a particular behavior does not have an effect on the acquirement of behaviors. An explanation for this could be that boldness is innate and resistant to social learning. Future experiments could be done to see if other behaviors, for example reproductive behavior, are more influenced genetically or by their social environment.
REU Mentors:  Jason A. Moretz/ Emilia P. Martins, Department of Biology

Serotonin projections to the inferior colliculus: A retrograde tracing analysis of raphe nuclei in mice
The purpose of this study was to further understand the modulatory effects of the neuromodulator serotonin (5-HT) in the inferior colliculus (IC), an important midbrain structure involved in auditory processing. This was accomplished in mice via quantification of cell distributions in different raphe nuclei, which are known to send serotonergic projections to the IC. We examined the distribution of serotonin cells in the raphe nuclei in mice by using the retrograde transport of green fluorescent retrobeads, pressure injected (0.1-1 µl) unilaterally or bilaterally into the inferior colliculus. This was combined with fluorescent immunostaining for serotonin after a 2-7-day survival period. Fifty-micron-thick brain sections were collected, immunostained for serotonin, and visualized with fluorescence microscopy. An abundance of retrogradely-labeled cells were present proximal to the IC injection site(s). Comparatively across different raphe nuclei, more retrogradely-labeled cells were found in the dorsal raphe nuclei (DRN) compared to fewer in the median raphe nuclei (MnR), with a few also appearing in the raphe magnus. Within just the DRN, further quantification of labeled cells revealed that labeled cells were mostly located in the medial wing, while there were fewer cells in the lateral wings. These results show that 1) mice are similar to other animals in the sources of serotonergic projections to the IC and 2) projections to the IC mostly come from a specific region of the DRN.
REU Mentor:  Laura Hurley, Department of Biology

Thermal environment influences morphology of developing Norway rats
Previously, Villarreal, Schlegel, and Prange (2005) reported that cool (17°C) housed rats develop shorter ears and tails than moderate (25°C) housed rats. In addition, they found cool-housed rats develop a preference for warmer air temperatures than moderate-housed rats. In order to elucidate possible biological mechanisms for the development of this seemingly counterintuitive thermal preference, we further assessed how the thermal environment influences morphological development of rats. Terminal morphology measures (body mass, body mass without coat, coat mass as a percent of body mass, and adrenal gland mass as a percent of body mass) of 32 22-day-old, 32 43-day-old, and 28 85-day-old rats were recorded. Results indicated that 22 and 43-day-old cool-housed rats had lower body mass with and without their coat than moderate-housed rats, p < 0.05. And 22 and 43-day-old cool-housed rats had higher coat mass as a percent of body mass than moderate-housed rats, p < 0.05. These results suggest the thermal environment substantially shapes the body morphology of juvenile rats. No differences were found on these measures in 85-day-old rats. In addition, no differences in adrenal gland mass as a percent of body mass were found at all 3 ages assessed. These results indicate that the morphological differences between cool and moderate housed-rats are not likely due to the cool temperature inducing a stress response. The results from this study have lead us to posit that the development of the previously observed thermal preference of cool-housed rats for warmer air temperatures than moderate-housed rats may be in part due to the lower body mass of juvenile cool-housed rats.
REU Mentor:  Henry D. Prange and Jill Villarreal, Medical Sciences

Effects of chronic stress on water maze performance in rats
Chronic stress has been shown to have the ability to impair learning in humans and in rats. These effects appear to be mediated by damage to the hippocampus that results from stress hormone release during exposure to chronic stress. Research on humans and rats has found stress to be related to hippocampal damage as well as memory and learning impairment. This study examines the effects of chronic stress on spatial learning in rats. Spatial learning was assessed by performance in the delayed matching-to-place paradigm in a water maze. Previous research with this paradigm has validated impaired spatial learning resulting from hippocampal lesions, stress hormone treatment, and stress. For this study, chronic stress was induced through long-term, inescapable restraint. Stressed animals were found to have deficits in Trial 1 performance for the nine Training Days and deficits in Trial 2 performance for 10-minute inter-trial intervals. Ongoing research will seek to statistically verify these results.
REU Mentor:  Preston E. Garraghty, Department of Psychology

Energy allocation and sickness behavior in Siberian hamsters
Many non-tropical mammals have evolved in fluctuating environments where resource availability can be vastly different across the seasons of the year. In response to these environmental changes, animals have evolved seasonal physiological and behavioral responses that allow them to anticipate and prepare for oncoming challenges in order to increase overall fitness. For example, during times of low resource availability (e.g. winter) animals will reallocate energy reserves into immediate survival challenges such as thermogenesis and reduce allocations to less critical responses (e.g. reproduction and immunity. In addition, many behavioral adaptations have co-evolved with energetic investment strategies to increase survival. Day length (photoperiod) is the primary cue mediating seasonal changes, and photoperiodic changes in the pineal hormone melatonin act as the biochemical signal mediating photoperiod responses. The purpose of the present study was to examine the physiological and behavioral costs of mounting an immune response and the role of melatonin in mediating these responses. Specifically we hypothesized that overall immune response and sickness behavior will be attenuated in melatonin (mel) implanted Siberian hamsters (Phodopus sungorus) as compared with control animals. Two experiments were conducted to test this hypothesis. Experiment 1 was tested the effects of food restriction on immune response in mel and control implanted animals. This was done by measuring antibody production response to an injection of the antigen keyhole limpet hemocyanin (KLH). Experiment 2 was conducted to determine the effects of lipopolysaccharide (LPS), an antigen that produces a robust sickness response, on a battery of sickness behaviors various in mel and control implanted animals. The results of these studies will be presented.
REU Mentor:  Gregory E. Demas and Devin Zysling, Department of Biology

Does 1 + 1 really equal 2? Genotypic and phenotypic interactions in expressed social behavior of Poecilia reticulata.
The phenotype of a group of animals reflects both the behavior of individuals and potentially interactions among individuals. We examined whether the phenotype of the group reflects additive, non-additive or a combination of additive and non-additive effects on the behavior of individuals within the group. We also sought to investigate whether the group phenotype as a whole could be described as additive, or whether it is different than the sum of its parts. We utilized an inbred strain of common guppies, Poecilia reticulata, which provides virtually homozygous subjects, eliminating variation in behavior resulting from genetic variation and allowing us to isolate interactions at the phenotypic level. All guppies were exposed to a predator stimulus and subjected to two test trials, once alone and once in a group, in random order. They were scored for time spent in close proximity to and oriented on the model, time spent foraging and agitated, and number of inspections. We found no net change in the mean phenotype displayed by individuals tested alone and individuals tested in a group. However, we did find evidence of non-additive effects within groups, with individuals differentially altering their behavior in response to the phenotype of other individuals within the group. Despite low repeatability an individual’s behavior alone is the best predictor of its behavior in a group. Our study therefore suggests that group phenotype is additive and therefore predicted, at least in part, by the mean individual phenotype.
REU Mentor:  Edmund Brodie III and Heather Bleakley, Department of Biology

Mobile versus stationary viewpoints affect blocking and facilitation between beacon and landmark learning in the floor maze
Blocking, when preexistent learning about one cue inhibits learning about a new, redundant cue, is known to occur readily in the temporal domain. In the spatial domain, its presence is not as clear. It is generally accepted that spatial learning is more complicated than can be described by the basic theories of associative learning, and spatial information may be encoded and integrated in multiple system. This experiment sought to examine the effects of moving versus stationary release and beacon positions on the interactions between beacon and landmark learning in rats. A square floor maze with four symmetrical quadrants was used, each quadrant containing a reward cup. A release basket was positioned in the center of each maze wall. Four treatment groups of Sprague-Dawley rats were studied: Moving Release/Static Beacon, Moving Release/ Moving Beacon, Static Release/Static Beacon, and Static Release/Moving Beacon. Each group received two trials per day for twelve days of training under these conditions, followed by the addition of landmarks and eight subsequent days of training in which all release and beacon positions were made static. A series of tests followed the training days. Overall, groups receiving a moving beacon in the first stage showed significantly higher latencies; this corresponds with an overall higher number of reward cups checked on the path to the goal. Groups receiving a moving release position in the first stage appear to learn more about the relevance of the beacon to the goal, while those receiving a static release position showed favor towards landmark cues. In the absence of a beacon, however, moving release groups demonstrated knowledge of landmark cues. Overall, this indicates that rats may encode knowledge of both beacon and landmark position simultaneously while demonstrating preference for one cue set, and this encoding is facilitated by receiving varied perspectives on the spatial area to be learned.
REU Mentors:  William D. Timberlake and Eddie Fernandez, Department of Psychology

Effects of 5-alpha dihydrotestosterone on the frequency modulation and udration of chirping behavior in Apteronotus albifrons.
Males and females of the species Apteronotus albifrons communicate through the sexually dimorphic EOD (electric organ discharge) frequency modulations they emit. Some of the short-term modulations are known as chirps, and males and females do seem to vary on the structure of these chirps. Androgens are thought to be at least partly responsible for the fact that males have a lower EOD frequency and that their chirps have a different structure than those of females. Androgen treatment has been found to lower the EOD frequency of females but has no effect on the rate or propensity of chirping in this species. The purpose of this study was to investigate whether the androgen 5-alpha dihydrotestosterone (DHT) has an effect on the structure of the chirps when implanted in both male and female A. albifrons. The DHT implants did not have the predicted effect on the EOD frequencies of the females, which would have served as an index of the effectiveness of the hormone treatment. This study did find, however, that females tended to increase the frequency modulation of the categorized low frequency modulations over time whereas the opposite was true of males. DHT implants tended to increase the frequency modulation of these low frequency chirps while control implants tended to decrease the frequency modulation of low frequency chirps over time. Even though the DHT implants did not have an effect on EOD frequency, these results suggest that it may have subtler effects on the structure of at least low frequency modulations. No effects were seen for the duration of chirps. This study should be repeated for conclusive findings about the effects of androgens on the structure of chirps in A. albifrons and analysis of the structure of chirp responses to specific stimulus frequencies should be pursued.
REU Mentor:  Troy Smith, Department of Biology

Electrophysiological evaluation of mice knocked-in with 140 CAG repeats
Huntington disease (HD) is a progressive, neurological disorder that is genetically inherited. It is autosomal dominant, where onset of the disease occurs with inheritance of one HD allele. The knock-in HD mice have 140 CAG repeats and are characterized by onset as late as 1 year of age, a much slower progression of disease in comparison to other models like the R6/2 line, with little known about the affected striatal region of the brain. Assessing the striatal function in the slow progression model, striatal electrophysiological activity was recorded between knock-in mice with 140 CAG repeats and wildtype littermate controls and neuronal firing rate was evaluated. Results suggest that there are no significant differences between knock-in and wildtype mice but there is a trend of higher firing rate for wildtype, control mice. Gender was also analyzed resulting in a sex difference in firing rates in the knock-in mice and, independently, in the wildtype mice; knock-in males also show some difference in firing rates when compared with wildtype males. The yielded results offer new insights that vary from the hypothesized mechanisms underlying HD previously found in the R6/2 strain and implicate some role of gender and testosterone-dopamine interaction as an explanation for the sex difference found in this relatively new HD model.
REU Mentor:  George V. Rebec, Department of Psychology

Song-sharing in lizards?: An exploration of display type-matching using a robotic lizard.
Neighboring male Sagebrush lizards, Sceloporus graciosus, produce and exchange species-typical push-up displays which vary in both syntax and delivery. This study tests for 1) the possibility of display-type matching in this species, and 2) behavioral differences in response to repeated exposure to two signal types. Two signal types (typical, atypical) were delivered to subjects using a mechanized lizard both in short-term tests and in repeated exposures for ten days. In short-term tests, lizards paid more attention to the robotic lizard when it produced atypical displays than when it produced the species-typical headbob display. After repeated exposures to the robotic lizard, subjects gave similar responses regardless of the display it produced, including a general increase in activity in comparison to behavior during short-term tests. Repeated exposures to different signals revealed only slight suggestion of differences between the displays produced. These findings suggest that lizards change behavior after repeated exposure to push-up displays, but provide little evidence for display-type matching.
REU Mentor:  Emilia P. Martins, Department of Biology

An assessment of classical eyeblink conditioning in rats using a tone and light CS and three interstimulus intervals
The modality of the conditioned stimulus (CS) and length of the interstimulus interval (ISI) used in classical eyeblink conditioning can affect an animal’s ability to produce a conditioned response (CR) which is correctly timed to coincide with the onset of the unconditioned stimulus (US). The current study explores this relationship between CS modality, ISI length and CR production. Rats were trained using one of two CS modalities, either a light or a tone, and one of three ISI lengths, either 280 ms, 580 ms or 880 ms, yielding six conditioning groups. Animals trained with the 280 ms or 580 ms ISIs show robust learning across all seven conditioning days regardless of CS modality. CRs in the 280 ms groups were the most accurately timed, with timing accuracy sharply decreasing at longer ISIs. Furthermore, the acquisition curve for animals trained with the tone and the 880 ms ISI was unusually high and almost flat, suggesting that there may be a confounding effect of the tone which is artificially heightening the CR count.
REU Mentor:  Joseph E. Steinmetz, Department of Psychology

Localization and Quantification of Substance P in Four Major Auditory Nuclei of the Mexican Free-Tailed Bat Tadarida brasiliensis Brain
Substance P (SP) is a neuroactive peptide that is involved in a variety of somatosensory functions and has excitatory effects in the central nervous system. Although several studies document the presence of SP in the auditory nuclei of rodents, analogous studies have not been done in the echolocating Mexican Free-Tailed bat. This study’s main purpose is to localize and quantify the amount of SP staining in the lower auditory system of this bat species. Immunohistochemical procedures were used to stain slices of the brain for SP. The slices were then visualized with fluorescence microscopy to determine the presence or absence of substance P in the facial nucleus, chosen as a control area, and in four major auditory nuclei: the cochlear nucleus, the lateral lemniscus, the lateral superior olive and the inferior colliculus. This study shows that, in comparison with adjacent areas and the control, there is little substance P present in the above-mentioned auditory nuclei of the Mexican Free-Tailed bat.
REU Mentor:  Laura M. Hurley, Department of Biology

Stickleback response to sign stimuli: comparing results of Field and laboratory experiments
The three spined stickleback, Gasterosteus aculeatus, has played an important role in ethology ever since they were investigated by Niko Tinbergen and found to have interesting and clearly identifiable behaviors. However, most of our knowledge of the stickleback comes from studies performed in aquaria. To assess and compare the established data found from tank research, we performed parallel aquaria and field studies at a marine laboratory in Asko, Sweden. We used already established protocol to compare the response of ten male sticklebacks in aquaria and ten males in the field using the following sign stimuli: simultaneous presentations of supergravid and normal gravid female dummies; normally gravid lordosis posture dummy female; red versus non-red male dummies. Males in aquaria showed strong responses to all the dummies, but males in the field had almost no response to any of the stimuli. The results of the experiments performed in the tank suggest that the fish in Sweden have similar behavioral responses to those found in previous aquaria experiments. However, the responses of the fish in the field indicated a dramatic decline in behavior toward the same sign stimuli, although both lab and field males were from the same areas. These results suggest that further comparative studies between field and lab conditions to gain a better understanding of the mechanisms behind the extreme differences found in male stickleback response behavior to sign stimuli in the field. This applies to many animal behavior studies as it is likely that most animals may behave differently in the field and lab due to differences in the amount of stimulation
REU Mentor:  William J. Rowland and Teresa Dzieweczynski, Department of Biology

The Effect of Rearing Temperature on Thermal Preference
The present study addressed if and when rat (Rattus norvegicus) pups will exhibit a behavioral preference for their rearing environment during the pre-weaning stage of development (postnatal day 0-21; P0-P21). During pregnancy dams where housed at 25oC. On P0 dams and their litter of 8 (n = 16, N = 32), were transferred to either a 17oC or a 25oC room. Morphological measurements were recorded every other day. Temperature preference was tested on P7, P14, and P21 with two 2-choice test (17oC vs. 25oC, and 25oC vs. 33oC). There was no significant difference across rearing temperature in morphology. Regardless of rearing condition and temperature preference trial, pups spent the majority of the trial in the warmer temperature zone. Mean estimated preferred temperatures for pups reared at 25oC were; 28oC, 29oC, 28oC, for P7, P14, and P21, and 29oC, 27oC, 27oC, for pups reared at17oC.
REU Mentor:  Henry D. Prange, Medical Sciences and Jill Villarreal, Department of Psychology

Behavioral test of an introduced population of threespine stickleback (Gasterosteus aculeatus) in Lake Michigan
Threespine stickleback have recently (8-20 years ago) invaded the Great Lakes. To date, there are several papers documenting the appearance and migration of this fish but there are no studies on their behavior in this new environment. Threespine stickleback are an ideal system to study because their behavior is very recognizable and they have been consistently studied for over 200 years. I wanted to study whether this new population responded to dummies of conspecifics and if they responded similarly to a population of stickleback from Long Island, of which we have data. The population of Lake Michigan stickleback most likely originated from an Atlantic population via the St. Lawrence Seaway. I ran tests on 18 males collected from Trail Creek in Michigan City, IN and documented their reaction to dummies of conspecifics. I compared these responses to data from a population from Long Island, which is possibly similar to the fish from where the Great Lake stickleback originated. The Lake Michigan stickleback reacted as expected, with the majority of courting directed to dummy females and attacks directed to the dummy males. These results suggest that the Lake Michigan population is a possible source of stickleback for future studies using dummies of conspecifics. In general, the Long Island fish responded more frequently than the Lake Michigan fish to the dummies. Further testing should be conducted to determine what factors caused the differences in behavior that we observed between the two populations.
REU Mentor:  William J. Rowland and Richard Granquist, Department of Biology

The influence of social conditions associated with social defeat on immune function in Siberian hamster (Phodopus sungorus)
Previous research has shown physical and psychological stress can negatively impact immune function. Activation of the hypothalamic pituitary adrenal (HPA) axis by a stressor triggers a host of physiological responses including the release of the stress hormone cortisol from the adrenal cortex. The present experiment investigated the social and environmental characteristics that suppress immune function in male Siberian hamsters (Phodopus sungorus). It was predicted that the greater concentration of cortisol found in the blood would correspond with the more severe social defeat session and thus the greatest immune suppression. Social defeat sessions (i.e. the introduction of an intruder hamster into a dominant resident cage) lasted for 15 minutes for five consecutive days and acted as a psychosocial stressor on the experimental hamsters. Experimental intruding hamsters were subjected to one of four conditions: hamsters were placed in 1) a clean cage, 2) a “dirty” cage without the resident present, 3) a cage separating the intruder and resident or 4) in direct contact with the resident. Prior to social defeat sessions each intruder was immunized with Keyhole Limpet Hemocyanin (KLH), an innocuous antigen that triggers a robust antibody response. Blood samples were tested for cortisol concentrations and anti-KLH immunoglobulin (IgG) concentrations. Cortisol levels were highest respectively in the intruder with direct contact with residents, separated cages, clean cages and the lowest concentration in dirty cages. Anti-KLH IgG concentrations followed the same trend found in cortisol concentrations. Contrary to the experimental hypothesis, these data reveal that immune function was enhanced by the severity of the social defeat
REU Mentor:  Gregory E. Demas and Devin Zysling, Department of Biology

Differences in the inspection behavior in Poecilia reticulate populations at different risk of predation
Common guppies, Poecilia reticulata, are small livebearing fish. In response to predators, guppies perform an inspection behavior, which has been suggested to provide longer survival periods, visual alarm signaling, predator deterrence and mate attraction. The majority of studies addressing differences in inspection behavior in response to levels of predation have been observational field studies. As such, we looked for differences in the frequency of inspection behavior between populations with a known predatory history under controlled laboratory conditions. In addition to interpopulation differences, some studies indicate intersex differences as well, and differences in inspection behavior between the sexes may have strong evolutionary implications for populations. Given the lack of consensus in the literature and the potential importance in understanding the selective forces operating on populations, the second question we wish address with this study is whether males and females differ in inspection frequency under predation risk. Eight to twelve fish from each of four different strains from the Quare II, Turure, Aripo and Oropuche Rivers in Trinidad were tested in groups of four to determine the number of times individuals in the group inspected, the amount of time spent in inspection, time spent in close proximity to the predator, latency to approach the predator and time doing other activities. While populations varied significantly in time spent hiding, number of inspection bouts and time spent in close proximity to the predator, only one behavior (hiding) was significantly correlated with the predation history of the population. Within three populations the sexes did not differ in any measure of inspection, however in a single population, females were marginally significantly slower to approach the predator than were males. As such, we did not find significant evidence to suggest that sexes vary in the inspection behavior. We did however demonstrate differences between populations which may correlate with predation history or other life history factors.
REU Mentor:  Edmund Brodie III and Heather Bleakley, Department of Biology

Developing a non-invasive method for measuring hormones in the Sagebrush Lizard (Sceloporus graciosus)
Injections and blood drawing are frequently used methods of applying and measuring hormones in subjects. An important question that arises for animal behavior scientists is: Can there be a less invasive way of applying and measuring hormones that is still accurate? This question is key because the pain and disturbance of an injection or bleeding can traumatize the animal which can alter behavior and hormone measures. In this experiment, we tested non-invasive femoral pore secretion assays for testosterone. A total of 44 males and 24 females were treated using a dermal patch which was applied using self-adhesive medical dressing. Treatment A was gonadotropin releasing hormone (GnRH) in a sesame oil vehicle. Treatment B was testosterone (T) in a sesame oil vehicle. Treatment C was sesame oil used as a control. There were fewer femoral pore secretion spots in lizards treated with GnRH and T as compared to controls. But the same pattern was observed also in FPS before treatment was applied. Therefore, our results do not support the use of the number of FPS spots as a method for inferring testosterone levels. An increase in size after treatment was noted, but not measured. Size may be an important consideration for future studies.
REU Mentor:  Emilia P. Martins, Department of Biology

The effects of variable-time (VT) food schedules on stereotypic behaviors in a captive adult polar bear (Ursus maritimus)
Stereotypic behaviors have been defined as repetitive movements or patters having no apparent goal or function (Mason 1991). Many variables have been correlated with stereotypies, but very little experimental research examined the functions these behaviors may serve. The following study examined how VT food schedules affect stereotypic and general activity in an adult polar bear at the Indianapolis Zoo. During observation, 21 behaviors across 5 locations were measure during baseline (no food) conditions and two VT conditions (VT-5min; VT-1min). The purpose of this project is to: (1) experimentally examine the effects that VT schedules have on stereotypic behaviors (2) examine the role of natural foraging patters in stereotypic behavior. Previously, fixed time (FT) schedules significantly reduced stereotypic activity when compared to baseline conditions. In captivity polar bears have a high incidence and frequency of stereotypies. Many captive endangered species are also known to perform stereotypic behaviors. The use of this strategy may provide a simple method to promote the health and welfare of numerous captive species.
REU Mentor:  William D. Timberlake and Eduardo J. Fernandez, Department of Psychology

Hormonal control of electrocommunication behavior in Apteronotus albifrons: Effects of Ovaprim on the production of short-term frequency modulations
In the electric fish genus Apteronotus, electric organ discharges (EODs) are often modulated to produce transient social signals known as short-term frequency modulations (STFMs). In the brown ghost knifefish (Apteronotus leptorhynchus), STFMs are sexually dimorphic in both quantity (number of STFMs/minute) and structure (frequency excursion and duration). In the black ghost knifefish (Apteronotus albifrons), males and females produce the same number of STFMs while STFM structure is dimorphic (Dunlap et al., 1998; Dunlap and Larkins-Ford, 2003; Kolodziejski et al., in press). However, A. albifrons have never been successfully bred in captivity and their mating behavior is poorly understood. It therefore remains unclear whether the lack of sexual dimorphism in STFM number in A. albifrons is real, or a consequence of insufficient breeding stimulation in captivity. In the current study, Ovaprim, a reproductive stimulant, was administered to male and female A. albifrons to aid in stimulating electrocommunication behavior typical of breeding fish. Behavioral tests were conducted 1, 7, and 14 days after treatment. No sex difference was seen in the total number of STFMs produced by A. albifrons before Ovaprim treatment. However after Ovaprim treatment, females produced significantly more STFMs than males. Females also produced more high frequency STFMs than males after treatment. These results suggest that Ovaprim stimulation affects both STFM number and structure with differential effects in each sex.
REU Mentor:  G. Troy Smith and Hanna Kolodziejski, Department of Biology

Betta be aggressive: using dummy fish to control audience behavior while examining audience effects in male Siamese fighting fish (Betta splendens)
There has been a trend in animal communication studies to study subjects in communication network rather than signaler-receiver relationships. Perhaps one way to do this is to examine how an audience might affect social interactions such as male contests. Recent investigations of audience effect in Betta splendens have shown that males modify their behavior towards another male when a live female or male audience is present. When using live conspecifics, one must take into account that the audience will not always behave the same and therefore the audience becomes a variable and may influence the results. In addition, if the audience is interacting with the subjects it is not really an audience but rather a third party of the interaction. Interacting males were tested under four treatments (dummy female, male and neutral fish and no audience) and their aggressive behavior was assessed. We measured the time spent by opponent and spent by audience also the following behaviors: gill erection, tail beats, and bites. There was no significant difference found among the treatments for any of the behaviors. This differs from previous studies using live audiences, which found that male-male interactions were influenced by the sex of the audience present. This shows that some factor other than just the mere presence of an audience affects the aggressive behavior of the interacting males. It can be concluded that when running an audience effect study using live subjects, one should consider whether the audience is a passive or active participant in the interaction. This study indicates that it is difficult to comprehend when a subject goes from being an audience to one of the interacting parties and, thus, we may need to redefine what an audience is.
REU Mentor:  William J. Rowland and Teresa Dzieweczynski, Department of Biology

The Effects of Corners of a Room on Blocking in the Morris Water Maze
The Morris water maze is a 1.52 M diameter pool containing a platform submerged just below the surface of the water that an animal must find using beacons and/or landmarks in order to escape the water. The current study addressed associative blocking in a water maze situation using rats as subjects. Associative blocking occurs when a rat learns an initial cue, often a proximal beacon, to find a platform but fails to learn subsequent cues, often distal landmarks, added to the room. Although several studies have found evidence supporting the occurrence of blocking, some studies have found facilitation in the form of improvement in learning about the second set of cues by the early training. The purpose of the current experiment was to further examine the determinants of blocking versus facilitation in a water maze situation. It was hypothesized that the corners of the room may have contributed to the facilitation of learning the distal room cues that occurred in previous studies. Two similar studies differing only in type of beacon were used in this experiment. The first study used a less salient displaced hanging beacon and the second study used a more salient pole beacon that protruded from the platform. Neither blocking nor facilitation of room cues was observed in either study. However, evidence suggests that salience of the beacon has some effect on preference of cues used to locate the platform. Rats that were trained with the displaced beacon (less salient) seemed to prefer to use room cues, while rats that were trained using the pole beacon (more salient) preferred to use a hanging beacon similar in shape to the pole beacon to locate the platform.
REU Mentor:  William D. Timberlake, Joe Leffel and Allison Kukuch, Department of Psychology

The Function of Beak Movement in the Vocalizations of the Monk Parakeet (Myiopsitta monachus)
The Monk Parakeet uses a complex system of vocal communication during social interactions. Avian communication has long been an important model in the neuroethological approach to studying human brain function. Despite sharing with humans a sensitive period for complex learning and development, performance-based feedback, and a discrete set of brain structures, birds have been considered to lack the vocal tract resonance filter that is crucial to speech production. However, consistent beak movement during sound production suggests that beak gape affects vocal production and recent studies suggest that songbird’s vary their beak gape to track fundamental frequency during songs, thereby maximizing the amplitude of some of the frequencies produced. We suspect that the parakeet’s use beak gape to shift frequency emphasis in the broadband spectrum of their calls. Using six parakeets, we measured the beak gape and energy distribution of alarm calls. Currently we are examining the data collected to identify correlations. If a significant correlation is found between beak gape and energy distribution of calls, it would suggest a system similar to the formants found in human speech. If parakeets produce formants, then we can conclude the post-production vocal processing system of parrots is more similar to human speech than to bird songs.

2003 REU Mentor:  Roderick Suthers and Gabriel Beckers

Effects of Male Status and Social Environment on Female Behavior in Sagebrush Lizards, Sceloporus graciosus
Although Sceloporus graciosus are typically territorial, they form dominance hierarchies at high densities. Social status in such groups may alter which lizards are able to interact within the group and how individuals respond to each other. In this study, we attempted to determine what physical attributes might predict male status, whether females respond differently to males of different status, and whether females with recent social experience respond differently than females without recent social experience to males. Males were measured for body size, tail length and symmetry of femoral pores, all predictors of dominance in other species. Dominance hierarchies were established by grouping four males and two females in each of six indoor enclosures. Dominant and subordinate males from each group were identified and presented to females in a y-maze. Secondly, females were presented chemical secretions from both dominant and subordinate males in their home cages and behaviorally assayed. We determined that dominant status is not related to symmetry of femoral pores, snout-vent length, or tail length, but that there is a positive but not significant correlation between weight and dominant status. Within the y-maze behavioral test, females with recent social experience did not differ from females without recent social experience in the amount of time spent with either subordinate or dominant males. We did find however, that females spent significantly more time with males possessing shorter tails than they did with males possessing longer tails. For the behavioral assay, we found that there is no difference in the amount of time the females spent near the dominant, subordinate or control samples, nor were there differences in observed numbers of behavior. However, females without recent social experience spent significantly more time near the samples, tongue flicked the samples significantly more often and were significantly more agitated.

2003 REU Mentor:  Bronwyn Bleakley and Emília Martins

The Effect of Serotonin on the Auditory System of the Mexican Free-Tailed Bat
Although previous studies show that serotonin can either inhibit or facilitate single auditory neurons, little is known about the overall effect of serotonin in the auditory system. Therefore, in this experiment, we looked at the impact of serotonin in the entire lower auditory system of the Mexican free-tailed bat by measuring the auditory brainstem response (ABR). This was accomplished by injecting the bats with fenfluramine, a drug that increases serotonin levels. Prior to injection with fenfluramine the bats were anesthetized with ketamine/xylazine or torbugesic to reduce their activiy. In making baseline measurements we encountered more variation in the peak latencies of the ABRs than reported in the literature. This variation is possibly correlated with level of alertness or anesthesia. If an anesthetic has an effect on the ABR it might influence data interpretation by changing the latency of the peaks, which could be mistaken for the fenfluramine effect. On top of this variation, fenfluramine did not change the peak latencies of the ABR. From these results we draw two conclusions. The first conclusion is that the ABRs in our study varied more than those that have been reported. Possibilities that would account for this are differences in our techniques from those reported or differences in the auditory system of the bat from those of other mammals. Our second conclusion is that fenfluramine either has no effect on the ABR latency or that its effect is smaller than the variation we encountered. Future experiments that can be done to further this study include doing this experiment during the bats natural wake cycle or doing a temperature control study because temperature can also affect peak latency.

2003 REU Mentor:  Laura Hurley

Audience Effect on Interactions of Betta splendens
Prior studies on eavesdropping in Betta splendens found that males increased the number of tail beats and gill flaring, and decreased the number of bites, a behavior used predominantly in male - male interactions, when in the presence of a female audience. Other investigations observed that when a male audience was present, interacting males decreased the time they spent near their opponent and increased the number of bites. We video taped male - male interactions with and without a female audience under 3 nesting conditions: 1 male with a nest, both males with nests and neither male had a nest. We then used the recordings to measure the number of tail beats and bites, gill flare erection rate, time spent near the opponent and the audience, and the time spent near the bubble nest (if present). Our investigation of audience effect on interactions between male B. splendens has shown only a significant difference in conspicuous displays. We found that subjects increased gill flare erection rate when a female audience was present. The amount of tail beats, bites, and the time spent near the male opponent showed no significant change in the presence of either audience. We also investigated whether or not the presence of a bubble nest influenced how female audience affects the male - male interactions. We found that the interacting males who had bubble nests neither increased nor decreased their aggressiveness toward their opponent. Even though we found no effect of the nest, we believe it was important to study because it has never been looked at before. Differences in our investigation and previous ones may be accounted for by the fact that previous investigators used a small number of males that interacted repeatedly. Some males even interacted multiple times. Our investigation only used each male once in an interaction. These differences also could have been affected by the time allowed for interaction. Our investigation allowed pre-exposure to the audience for 5 minutes and 20 minutes for interaction. Prior studies allowed 3 minutes of pre-exposure and 10 minutes of interaction time. The results of our study suggests that having a female audience does affect the aggressive display behavior of interacting male Betta splendens.

2003 REU Mentor:  Teresa Dzieweczynski and Dr. William Rowland

Attempts to Hormonally Manipulate Sexual Behavior of Female Threespine Stickleback (Gasterosteus aculeatus)
I investigated how sexual motivation affects male preference in female threespine stickleback (Gasterosteus aculeatus). I attempted to increase sexual arousal by treating female subjects with Ovaprim, an aquaculture drug that contains gonadotrophic releasing hormone (GnRH) used to induce spawning behavior in fishes. I first tested all subjects’ responses to two moving dummies, one representing a nuptially colored male and the other a neutrally colored male. I then injected the females intraperitonially with either Ovaprim (experimental group) or a propylene glycol control and retested each subject at 6, 10, 24, 30, and 48 h post-injection. Females were then injected a second time, and tested again at 6, 24, and 30 h post-second injection. “Following dummy behavior” decreased from pre- to post-injection in both experimental and control females, and no females directed strong courtship response to either dummy. This weak response suggests that the subjects were out of condition and tested too late in the spawning season. If the females’ gonads were well past their maximal development, this might preclude any effect of Ovaprim, which increases development and hormone secreting activity of the gonads. The disturbance from the injection procedure may also have contributed to the absence of a clear sexual response in the Ovaprim-treated fish. These potential complications thus preclude me from drawing any conclusions about the effectiveness or ineffectiveness of Ovaprim as a modifier of sexual behavior in female threespine stickleback.

2003 REU Mentor:  Richard Granquist and Dr. William Rowland

Signal Perception in Lizards: Motion Cues and General Body Morphology as Releasers of Aggressive Behavior in the Sagebrush Lizard (Sceloporus graciosus)
Many lizards communicate through visual displays, which are used primarily in territorial acquisition and defense. In this study, we examined the importance of general morphology in aggressive behavior of sagebrush lizards (Sceloporus graciossus). Thirty-two males with the exception of one due to equipment failure were used in the experiment. The males were presented with two programmed models, a robotic lizard and a red cube, which performed the aggressive displays of a sagebrush lizard. Previous studies using models have indicated that many animals tend to respond to sign stimuli or releasers that resemble the general morphology of their species. Behavior responses to robot stimulus have produced the same results as live conspecifics. Our goal was to determine the importance of motion cues, relative to general morphology, in eliciting aggressive behavior in lizards. To test this, four treatments were shown to the male lizards, which consisted of robot lizard/aggressive, robot lizard/still, cube/aggressive display, and cube still. We hypothesized that the sagebrush lizards would respond more to the displaying robot because of the general morphology and displaying behavior. Each experimental trial was videotaped and later scored on specific aggressive behavior. The lizards approached the lizard model (moving or still) more than the cube. They responded differently to motion depending on whether it was the lizard model or a cube. Each lizard differed in overall responses to each treatment.

2003 REU Mentor:  Dr. Terry Ord and Dr. Emilia Martins

Pretraining Norway Rats with Distal Cues does not Block Control of Foraging by Proximal Cues
Animals use objects and distant landmarks in their environment as points of reference for remembering potential locations for nesting, safety and finding food. The purpose of our study was to discover if initial training of rats with a subset of spatial cues would interfere with (block) the learning of additional spatial cues. The traditional concept of blocking is grounded in associative learning models of cue competition. These models claim that once a predictive cue (a CS) produces a conditioned response (a CR) at its asymptotic level, no further associations can be made between other stimuli (CSs) and the CR. Previous research using the Morris water maze (a spatial task that requires the animal to find the location of a hidden escape platform in a large circular pool) has provided considerable evidence that pretraining with a beacon close to the platform interferes with learning to find the platform using room landmarks. (Rodrigo, et. al, 1997; Roberts & Pearce 1999) In our study we followed the experimental design of water maze studies but instead of observing escape behavior to a platform, we examined foraging behavior in a large open field, and we reversed the direction of potential blocking. We tested whether rats that received pretraining with distal room cues (landmarks) were able to learn that an additional proximate cue (a beacon) also predicted the location of food. Given the blocking hypothesis, we expected pretraining with room cues to interfere with learning the prediction by the beacon. Given the alternative hypothesis--that animals should learn readily about proximate cues--we expected that pretraining with only the room cues would not block learning about the beacon.

During training each rat was placed in a 10’ square arena with four cups positioned at equal distances from its corners. Food could only be found in one cup that remained in the same location for each rat during both training stages. The blocking group was given twelve days to learn to locate food by using only room cues as a reference. Then, both blocking and control groups received twelve days of compound conditioning with both room cues and a beacon placed near and above the food cup present.

We performed three tests to assess the degree to which the beacon guided foraging in the absence of the landmarks: first, by presenting the beacon alone in the absence of room cues; second, by moving the beacon to a new position to determine the extent to which the rats explored the quadrant indicated by the room cues versus the beacon and other two quadrants; and third, by removing both the room cues and beacon to examine whether rats were able to locate the food cup based only on a basic orientation in the room. We observed order of choices and time spent in the room cues and beacon quadrants.

Overall, our results show that blocking does not occur in a spatial foraging task when pretraining with distant landmarks precedes compound conditioning with a proximate cue. Further, when compound conditioning is the only training received, a beacon does not overshadow learning the predictive value of distal landmarks, given that room cues were used by the control group as a more reliable reference when the beacon was shifted from its usual position.

2003 REU Mentor:  Joe Leffel and Dr. William Timberlake

Four Leaf Clovers and Rabbit’s Foots: The Role of Prior Training in “Superstitious” Behavior
Researchers have long speculated on the basis of pigeons’ behavior on a short fixed time (FT) schedule in which the animal receives food every 15 seconds no matter what behavior they are performing. Skinner (1948) first described the pigeons’ behavior on this schedule as “superstitious;” he thought that the behaviors that appeared on the FT schedule were arbitrary and maintained by coincidental pairings with food. Other researchers hypothesized that behaviors on FT schedules were a form of stimulus substitution (Simmelhag & Staddon, 1971) or a part of a niche related foraging sequence (Timberlake & Lucas, 1985). The purpose of this experiment was to determine whether prior training would change the behavior that appeared on a subsequent FT schedule. If the behavior after training remained the same as during training, then there may be a role of accidental reinforcement in determining behavior under a FT schedule. If, on the other hand, the behavior shifted into wall directed behavior, this would be a clear indication that accidental reinforcement is not the primary mechanism driving behavior but rather a niche related foraging mechanism. Eight pigeons were trained to turn or approach the back wall of a chamber on a FI-15s, in which the first correct response after 15 seconds was rewarded, and were then placed on a FT-15s schedule while their behavior was tracked every 3 seconds. By day 4 of the FT-15s schedule, 5 out of 8 of the pigeons dropped into the typical pattern seen in a FT schedule of locomotion followed by wall directed behavior at the hopper wall with very little other behavior occurring during the sessions. Two back wall trained birds’ behaviors were altered by the training and began to alternate wall directed behavior at the hopper wall and the glass wall of the chamber. Finally, one bird maintained the trained behavior of turning for 10 sessions before beginning to break down into wall directed behavior. Prior training seems to have some persisting results on behavior that occurs during fixed time food presentations, but the fact that all behaviors were eventually replaced by some form of wall directed behavior suggests some kind of niche related foraging mechanism is directing behavior under the FT schedule.

2003 REU Mentor:  Eddie Fernandez and William Timberlake

Spiny Mouse (Acomys cahirinus) Parent-Offspring Contact Patterns in a 3-Chamber Habitat: Litter Birth to Postnatal Day 8
In a lab environment spiny mice have been reported to exhibit biparental care (Makin & Porter, 1984; Szijarto, Coffee, Boyle, Bailey, Mulé, Iacovone, & Deni, 1985). These reports, however, are based on limited time samples that may inaccurately represent sire involvement in offspring care. In this study, families were housed in a 3-chamber habitat that allowed the mice to actively determine proximity and contact with one another. Parent-offspring contact patterns [Dam-Pup(s), Sire-Pup(s), and Dam-Sire-Pup(s)] of 4 families were described on postnatal days 0, 2, 4, 6, and 8 of their second litter, using 24-hr time-lapse video samples with a12:12 light-dark cycle (lights on at 0700). Average intra-observer reliability was greater than 95%. The results from this study indicated that the time spiny mouse families spend in Dam-Sire-Pup(s) contact increases as time spent in Dam-Pup(s) contact decreases with pup age.

2003 REU Mentor:  Jill Menge and Dr. Jeffrey Alberts

Social Interactions Among Zebrafish (Danio rerio): Shoaling and Inspection Behavior
The subjects, zebrafish (Danio rerio), were taken from two different genetic strains that differ in shoaling placement in laboratory tanks and degree of fright response. Shoaling behavior is observed in both strains; this experiment tested whether shoaling is an anti-predator mechanism or a social behavior. I ran individual zebrafish from the two different genetic strains through four different treatment conditions: exposure to a solitary conspecific dummy, exposure to a conspecific dummy while a live shoal is visible in an adjacent tank, exposure to a solitary predator dummy, and exposure to a predator dummy while a live shoal is visible from an adjacent tank. Preference zones, predator inspection behaviors, and freeze time (a fright reaction) were recorded. Both strains spent a significant amount of time by the live shoal when it was present, but showed no significant difference in preference for the shoal when the predator dummy or conspecific dummy were presented. The domesticated strain (TM1) showed a significant preference for the conspecific dummy when it was presented alone when compared to preference for other dummy stimuli in any of the other three treatments, while the wild strain (Nadia) showed no significant preferences to dummy stimuli. The Nadia strain froze up more than the TM1 strain, regardless of stimuli. Predator inspection behavior was observed and recorded, but no significant trends were found. These findings suggest that shoaling behavior is both an anti-predator mechanism and a social behavior. Also, it appears that freezing at the bottom of the tank may be an anti-predator response for the Nadia zebrafish, and that any novel stimulus is perceived as a threat.

2003 REU Mentor:  Teresa Dzieweczynski and Dr. William Rowland

Estrogens Act at Target Musculature to Masculinize SNB Motoneuron Dendrite Growth
Androgens and estrogens are both important factors which act to establish sexual dimorphism in the spinal nucleus of the bulbocavernosus (SNB) in rats. Estrogen (E) plays a crucial role in masculinizing dendritic morphology in the SNB during the initial growth phase of development [postnatal (P) day 7-P28]. However, SNB motoneurons themselves do not accumulate estradiol during development, although they do receive afferents from, as well as send projections to, E targets. Different E sites of action have been examined to determine which are responsible for supporting dendritic growth in the SNB. Dorsal root ganglia contain E-concentrating neurons, however, dorsal rhizotomy does not alter motoneuron dendritic development in the SNB of normal males or E-treated castrates. SNB motoneurons receive afferents from E-targets in sexually dimorphic brain regions, yet previous research has shown that E-regulated dendritic growth in the SNB is not mediated suprapinally. The goal of this study was to assess whether estradiol acts in the target musculature of the SNB, the bulbocavernosus (BC), to masculinize dendritic growth.

We attached Silastic implants impregnated with tamoxifen (.2 mg), an estrogen receptor antagonist, to the left bulbocavernosus on P7 and assessed the effect this had on dendritic growth in the SNB. SNB motoneurons were retrogradedly labeled with cholera toxin-HRP at P28 (when dendritic length is normally maximal) and reconstructed in three dimensions. Dendritic arbor was also assessed in a control group of normal males (P28) and a control group that received tamoxifen implants in the interscapulary area to control for potential systemic effects of tamoxifen. Dendritic length per motoneuron in the SNB for normal P28 males ranges from 4131 µm to 7529 µm (average= 6246 ± 398 SEM). In the current experiment, dendritic lengths measured in a normal male (7440.6 µm) and in a male with an interscapular tamoxifen implant (5196.72 µm) were both well within the normal range. However, the average dendritic length measured in two animals with muscle tamoxifen implants (m = 3116.56 ± 796.21) was well below normal values, suggesting that tamoxifen attenuated dendritic growth by blocking estrogen action at the SNB target musculature. These results support the hypothesis that estrogens act at the BC muscle to support dendritic growth in the SNB during development.

2003 REU Mentor:  Dr. Dale Sengelaub

Species Differences, Sexual Dimorphism, and the Effects of Arginine Vasotocin on Modulation of Electric Organ Discharge in Apteronotus leptorhynchus and A. albifrons
In weakly electric fish, an electric organ in the tail emits an electric organ discharge (EOD) used to communicate with other electric fish or to electrolocate objects or other organisms. This discharge can be modulated in both frequency and form to create “chirps.” Type I chirps are used in courtship, are longer, and generally involve a greater increase in frequency followed by a decline slightly below baseline EOD frequency. Type II chirps are used in an aggressive display and are of shorter duration, involve smaller increases in frequency, and generally do not fall below baseline EOD frequency (Engler et al 2000). In our preliminary project, we replicated three main studies. Kent Dunlap found that males of A. leptorhynchus chirp more than females and that this sexual dimorphism does not occur in A. albifrons (Dunlap et al 1998). Engler et al (2000) discovered that although both males and females of A. leptorhynchus produce the type II chirps, only males produce type I chirps. We also confirmed that males produce a higher proportion of type I chirps to female stimulus frequencies than to male frequencies, which correlates with the use of type I chirps in courtship (Bastian et al). In addition to the replication of these three studies, we found that although A. albifrons produces significantly fewer chirps than A. leptorhynchus, this species exhibits more gradual frequency rises (GFRs) than A. leptorhynchus. GFRs have a less pronounced, or more gradual rise in frequency than chirps, and also have a much longer duration. The behavioral function of these modulations is not well documented. However, our research found that more GFRs were elicited from A. albifrons with playback frequencies that resembled a fish of the same sex as the test subject. It has been shown that AVT has a dose dependent effect on the chirping behavior of male A. leptorhynchus (Bastian et al). Our study sought to replicate this discovery and to investigate the effects of AVT in females of A. leptorhynchus, and both sexes of A. albifrons. Test subjects were stimulated with three artificial EODs. This control was repeated following an injection of saline, and a third time, following an injection of AVT. We found that the injection of AVT increased the ratio of type I to type II chirps in males of A. leptorhynchus, which replicates Bastian’s results. Thus, AVT increased the propensity of males to produce the chirp used in courtship interactions. We also found that in females of this species, type II chirps displayed a significantly higher frequency modulation, resembling the type I chirps of males. Injections of AVT had no significant effect on the chirps or EOD modulations of either sex of A. albifrons. However, further research might reveal changes not measurable by our methods.
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2002 REU Mentor:  Dr Troy Smith, Department of Biology

Effect of Birth Fluid on Paternal Responses of Adult Male Spiny Mice (Acomys cahirinus)
The mechanisms facilitating paternal care of adult male spiny mice are poorly understood. We investigated the effects of experience and expectancy on infant-directed behavior and asked whether the presence of birth fluid on a newborn’s skin augments paternal behavior in adult male spiny mice. Responses to novel newborns bearing birth fluid and to clean neonates were assessed in four groups of adult male mice varying in paternal experience and expectant state: Non-Experienced Non-Expectant, Non-Experienced Expectant, Experienced Non-Expectant, and Experienced Expectant. Paired t-tests indicated that Experienced Expectant males spent significantly more time licking, handling, contacting, and laying on the newborn after it was coated with birth fluid, p < .03. Experienced Non-Expectant, Non-Experienced Expectant, and Non-Experienced Non-Expectant males were unaffected by the presence of birth fluid on pups. An ANOVA conducted for each of the infant-directed behaviors assessed indicated that adult males did not show group differences in paternal responses when the newborn was clean or coated with birth fluid. This appeared to be due to the variability in the paternal responses within each of the groups. These data indicate that experience, expectancy, and birth fluid may be important factors in the expression of infant-directed behaviors. Further studies are needed to determine the factors underlying individual differences in paternal responses of adult male spiny mice.
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2002 REU Mentor:  Dr Jeff Alberts and Jill Menge, Department of Psychology

Effects of Sex Ratio on Territoriality and Social Interactions in a High Density Population of Sagebrush Lizards (Sceloporus graciosus)
Territoriality has been shown to be the ancestral state in lizards with the homoplasious loss of territoriality occurring throughout the phylogeny. Variations in degree of territoriality among species may be due to differences in life-history patterns, availability of resources, access to mates, or ontogeny and phylogenetic constraints. Previous research has indicated that both density and population substructure may affect the loss of territorial behavior. It has been observed that individuals in high density populations frequently form aggregations dominated by a single male rather than maintain territories. We used sagebrush lizards (Sceloporus graciosus) to explore the effects of resource limitation, in the form of available females, on territoriality and social interactions. Lizards were placed in high density-populations with three different sex ratios to control any given male’s potential access to mates. Treatments consisted of eight males, seven males and one female, or four males and four females. Focal observations on each cage were used to assess types and levels of interaction between the lizards in each treatment.
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2002 REU Mentor:  Dr Emilia Martins and Bronwyn Heather Bleakley, Department of Biology

Effects of Diet and Age on a Sexually Dimorphic Plumage Trait in Male Dark_eyed Juncos (Junco hyemalis)
In many avian species, females use male secondary sexual traits to choose between potential mates. One common secondary sexual trait in birds is a badge, or patch of feathers. These ornaments may help the female gauge the genetic or phenotypic quality of the male. Nutritional condition may be one factor affecting the quality of such a signal. One trait that has been shown to be important in female mate choice is the white tail feather badge (tail-white) in dark-eyed juncos (Junco hyemalis). Tail-white increase with age in both sexes and is modestly sexually dimorphic (males being darker than females). To assess whether tail-white was affected by nutritional condition, we varied protein content in the diets of 39 male dark-eyed juncos during feather growth. After removing four tail feathers, each individual (19 AY, 20 AO) was assigned to either a low protein or a high protein diet. After regrowth, the four replacement feathers were pulled for analysis. In order to measure the effects of diet on tail-white area, the area of tail white in relation to total feather area was calculated using computer analysis of digital images. In order to measure the effects of diet on signal quality, the reflectance spectrum of each feather was measured using an UV-Vis spectrometer, which can detect reflectance throughout the avian visual spectrum. From these data, we calculated mean reflectance to determine the brightness of the ornament. Individual variation in rate of feather growth in response to diet treatment was measured by measuring the width of feather growth bars with calipers. A Doubly Multivariate Repeated Measures ANOVA was used to determine if a change occurred between the first set of feathers to the second and whether this change depended on diet or age. Although AY and AO birds reacted differently diet treatment did not significantly affect any of the variables measured. Body mass and length of feather decreased in the AY birds, whereas only the length decreased in AO birds. Also, percent tail white increased in both groups, although the difference was greater in AY birds, causing AY and AO tail-white values to be similar in the second set of feathers. Brightness of tail-white increased in the fifth rectrix of AY birds and stayed the same in the fourth rectrix. However, the AO birds showed a decrease in brightness of tail-white. Diet appeared to have an affect on the rate of feather growth, as indicated by the width of the growth bars, but this difference was marginally non-significant. In conclusion, tail-white may be a more reliable signal of age than of nutritional condition.
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2002 REU Mentor:  Dr. Ellen Ketterson, Joel McGlothlin, Deb Duffy, Department of Biology

The Ups and Downs of Social Mingling: The Effects of Social Interaction on Immune Function and Reproduction in Siberian Hamsters (Phodopus sungorus)
As their scientific name implies, the primary cue that Siberian hamsters use to adjust their physiological and biochemical rhythms is photoperiod (day length). Other environmental cues may, however, play a part in preparing the biological systems of this particular species of hamster for seasonal changes. The goal of this experiment was to measure the effect of social interactions on reproductive and immune responses in male and female Siberian hamsters. After a brief acclimation period, 36 hamsters (18 male and 18 female adult hamsters $ 50 days of age) were separated into 4 housing conditins (6 isolated singles of each sex, 6 male and female pairs, 3 males/male pairs, and 3 female/female pairs) for three weeks. Weekly focal behavioral observations and body weights were recorded throughout the housing period. At the end of the three-week housing period, animals were injected with the antigen Keyhold Limpet Hemocyanin (KLH) to elicit and antibody response, and returned to their respective housing conditions. On post-injection day 5, hamsters were bled for serum samples and killed. Necropsies were performed for further analysis of reproductive tissues and spleens. This research will hopefully lead to more research that will unmask the healthiest living conditions for both domestic and experimental Siberian hamsters.
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2002 REU Mentor:  Dr. Greg Demas, Kelly Polacek, Department of Biology

The Physical Properties of Primate Ribs: A Comparison of Primate Locomotor Groups
The rib cage is a very important structural element within the context of locomotion. Aside from concealing and protecting the body’s vital organs, it also acts to absorb and dispel forces imparted on the body by postural requirements during movement. We hypothesized that an individual rib adopts a shape – most notably the cross-sectional shape – that will most greatly minimize this positional-related stress upon the structure, and sought to quantify this conjecture. We sampled right ribs from 50 individuals across eight different locomotor categories (quadruped, leaper, brachiator, biped, etc.) and among healthy, adult specimens. In phase one the maximum and minimum diameters of the middle rib (i.e. 6th or 7th) were taken at 50% total length of the rib as a preliminary assessment of cross-sectional shape. The ratio of maximum to minimum diameter was then used to determine the general shape of the rib (i.e. a ratio closer to 1.00 represents a more rounded rib and a ratio closer to 2.00 represents a more blade-like rib). In phase two we CT scanned the 4th, 7th, and 10th ribs at 25%, 50%, and 75% of their total length (a total of approximately 400 cross-sectional images) to get a more accurate assessment of shape and bone distribution within the rib. Phase one results showed that ratios between groups were significantly different (p<.006). Groups can be arranged from most rounded ribs in the suspensory group to least rounded (most blade-like) in the archaeological humans. Following the suspensory group roundedness decreases from vertical clinger and leaper to brachiator/armhanger, to arboreal and terrestrial quadruped, and finally to the second most blade-like category, leapers. It is possible that a more rounded rib would be more rigid to bending stresses in multiple directions and hence selected for in animals having to endure such stresses, as opposed to a blade-like rib that is rigid in essentially one direction. The preliminary results from phase two seem to support our results from phase one.
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2002 REU Mentor:  Dr. Kevin Hunt, Kristian J. Carlson, Department of Anthropology

Effect of Birth Fluid on Maternal Responses of Adult Female Spiny Mice (Acomys cahirinus)
The mechanisms facilitating maternal care of adult female spiny mice are poorly understood. We investigated the effects of experience and expectancy on infant-directed behaviors and asked whether the presence of birth fluid on a newborn’s skin augments maternal behavior. Responses to novel newborns bearing birth fluid and to clean neonates were assessed in four groups of adult female mice varying in maternal experience and expectant state: Non-Experienced Non-Expectant, Non-Experienced Expectant, Experienced Non-Expectant, and Experienced Expectant. Paired t-tests indicated that Experienced Expectant females spent significantly more time licking, handling, contacting, and laying on the newborn after it was coated with birth fluid (p < .05). Experienced Non-Expectant, Non-Experienced Expectant, and Non-Experienced Non-Expectant females were unaffected by the presence of birth fluid on pups. There were group differences for durations females spent transporting and laying on clean newborns (p < .05), and for contacting and laying on birth fluid-coated newborns (p < .05). These data indicate that experience, expectancy, and birth fluid may be important factors underlying the expression of infant-directed behaviors of adult female spiny mice.
 |CURRENT INFO|

2002 REU Mentor:  Dr. Jeff Alberts, Jill Menge, Department of Psychology

Time-place Discrimination by Rats Diving in a Water Maze
Encoding the spatial location and time at which significant biological events occur is thought to be a fundamental way in which memory is organized in animals. Many species have been shown to possess timing systems specialized to anticipate significant events that recur every 24 hours. Few organisms have been shown to associate these significant events with a specific location, the phenomenon of time-place discrimination. Failures may have been due to the lack of choice effort required. In the present study, we used a water maze for rats adapted to diving to test time-place discrimination as a function of both the difficulty of task (the depth they dove) and the nature of the reward (escape from the water with or without food). Each rat was exposed to a water maze consisting of 4 metal boxes spaced evenly around the periphery, one of which contained a platform the rat could reach by a combination of swimming and diving. For each subject, the platform was placed in a different box in morning and afternoon sessions. Half the subjects received a food reward in addition to the platform reward. The rats were tested at two trials for each morning and afternoon session for 26 days. As the study progressed, the subjects were required to dive deeper to enter the boxes, making their choices more effortful. Although the rats learned to choose either the correct box for the morning and afternoon sessions, their choices were not related appropriately to the time of day; therefore the rats did not successfully demonstrate time-place discrimination. The absence of time-place learning may be due to the absence of sufficient effort in diving or to the absence of food deprivation and foraging behavior.
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2002 REU Mentor:  Dr. William Timberlake, Joe Leffel, Department of Psychology

Motor Behavior of Transgenic Mice with Huntington’s Disease Receiving Vitamin C
Huntington’s disease (HD) is a progressive neurological disorder that affects motor behavior. The R6/2 transgenic strain of mice carries approximately 140-150 CAG repeats and exhibits characteristics similar to human HD. Previous research has shown that 300mg/kg ascorbic acid (vitamin C) improves motor behavior in HD mice (Rebec et. al 2002). The current experiment tests the effectiveness of a lower dosage in the amelioration of symptoms. HD mice and littermate controls were given either 100 mg/kg ascorbic acid or an equivalent volume of saline for three consecutive days for a four week period. On the fourth day of each week of treatment, mice were observed in a plus maze, activity box, and an open arena. No significant differences were found in behaviors between the two HD groups; however, high morality among vehicle-treated mice led to a small sample size.
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2002 REU Mentor:  Dr. George Rebec, Scott Barton, Program in Neuralscience, Department of Psychology

The Effects of Testosterone and Estrogen on Cortical Plasticity in Rats
The present experiments focus on the potential roles of testosterone and estrogen might play in structural and activational changes in the somatosensory cortex, specifically, the whisker barrel fields in SI cortex of rats. Experiments using this model system have demonstrated the importance of sensory inputs to the brain’s normal development, and its plasticity in response to altered patterns of sensation. A rat’s whiskers (or vibrissae) are very important sources of sensory input: they give the animal information about place and movement. Each whisker sends its input to a grouping of neurons called barrels in the rat’s contralateral cerebral cortex. Thus, the arrangement of the barrels is “characteristic and consistent” and the one-to-one correspondence between whisker and bareel makes this are of cortex a good model for studying cortical plasticity. By combining partial sensory deprivation with gonadectomy in adult rats, the present experiments were intended to reveal any contributions that steroid hormones might make to cortical plasticity.
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2002 REU Mentor:   Dr. Preston Garraghty, Department of Psychology

Preference for Male Body Size in Female Sailfin Mollies (Poecilia latipinna): Comparing Simultaneous versus Sequential Presentation
A variety of methods have been used to assess female mate choice. The technique best suited for such an endeavor depends upon how females encounter males. In nature, females encounter males both singly and in groups and can therefore sample potential mates both simultaneously and sequentially. Female sailfin mollies (Poecilia latipinna) prefer males of larger body and fin size. We therefore hypothesized that female sailfin mollies would more strongly prefer larger males when the males were presented simultaneously than when presented sequentially. To test this, we presented females with five male dummies that differed in body size. The dummies were presented both simultaneously and sequentially to the female. In the sequential presentations, dummy males were presented along with a neutral female dummy, to control for possible schooling effects. Female preference functions were established for both experiments and compared. Females spent significantly more time with dummy males over the dummy female in all five sequential treatments. Females also tended to spend more time with larger dummy males over smaller ones across treatments. However, females exhibited a significantly stronger preference for larger male dummies when they were presented simultaneously than when presented sequentially. Therefore, female sailfin mollies more strongly prefer larger males when they can make direct and immediate comparisons between them. These results highlight the importance of considering how females encounter potential mates in nature when designing experiments to assess mate choice in a given species. They also emphasize how the distribution pattern of potential mates may influence mate choice and sexual selection in general.
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2002 REU Mentor:   Dr. William Rowland, Dave MacLaren, Department of Biology

Left Out in the Cold: A Look at the Development of Huddling in Mus musculus
Huddling is a common thermoregulatory behavior readily seen in many neonatal mammals, including rodents, whereby individuals aggregate and conserve heat generated by themselves and their littermates. Although this phenomenon has been studied in several species, its characteristics and development have not been charted yet in the common laboratory mouse (Mus musculus), a species that is important as a model system for many fields of research. Thus, we sought to illuminate the behavioral development of C57BL/6J mice, a popular laboratory strain. We examined their huddling behaviors at ages 4, 8, 12, and 16-days old (day of birth = Day 0). Four littermates were placed together in a temperature-controlled chamber and sequentially exposed to temperatures of 35°C, 30°C, 25°C, and 20°C, each for a 30-minute period. Their responses were videotaped and later analyzed for each group’s surface area-to-mass ratio, an indicator of huddling. Our results showed significant differences in huddling behavior at different ages. Although three of the age groups showed significant decreases in surface area-mass ratio as the temperature drops, this decrease was not significant for the 4-day-olds: there was no change in huddling in this age group across temperature conditions. In contrast, the 16-day-olds formed huddles when the temperature drops from 35°C to 30°C, before the other age groups increase their aggregative behavior. Both 8-day-olds and 12-day-olds showed a pronounced decrease in surface area-mass ratio as the temperature dropped from 30°C to 25°C but showed approximately the same amount of huddling as did the 16-day olds at 20°C. There are at least two possible explanations for the developmental differences we observed. First, younger mouse pups may not be able to maintain a huddle, due to their limited motor development. Young mouse pups in our lab, however, appear to be active, although perhaps not directed in their activity. Second, huddling might be a learned or acquired behavior that both is seen at warmer temperatures and increases more quickly as pups grow older and become more proficient at huddling. In may be that younger pups (here, Day 4 pups), who have not had as much experience with littermates, fail to huddle and are left out in the cold.
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2002 REU Mentor:   Dr. Jeff Alberts, Thalia Schlossberg, Department of Psychology

A Potential Mechanism for Individual Recognition in (Uta stansburiana)
Although numerous studies have suggested that individual recognition occurs in animal species, relatively few studies have sought to find the mechanisms that animals use to perform this recognition. Side-blotched lizards (Uta stansburiana) are known to show "dear enemy" recognition, but the mechanism for this recognition has not been studied. We sought to find a possible mechanism for recognition by examining pushup displays. Lizards emit pushup displays while they move through their territory, likely as a means of communication. Pushups are vertical displacements of the anterior portion of the animal, which result from the extension of the forelimbs. To examine these displays, animals were placed individually in trial boxes, which used their mirror reflection to elicit behavior. Pushups were plotted to create a display action-pattern graph. From these DAP graphs relative amplitude or duration of display units were recorded for analysis. Pushups were examined for repeatability over three time scales: 1) within a series of pushups 2) pushups from different series on the same day and 3) for series that occurred on different days. Use of a discriminant analysis function resulted in the correct assignment of 72% of all pushups. Within series, classification resulted in 86.2% success. Pushups within a time trial were correctly classified 71.1% of the time and 76.6% for consecutive day trials. Analysis shows that there is much less variation within individuals than between individuals. Our results indicate that differences in pushup structure could be used to discriminate between individuals. Playback studies will be necessary to determine whether lizards utilize pushups for "dear enemy" recognition.
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2001 REU Mentor:  Yoni Brandt, Department of Biology (Brodie lab)

If a Fish Bites and There's No Hydrophone in the Water, Does it Make a Sound?: Profiling the Contact Noises of Male Biting in Threespine Stickleback, (Gasterosteus aculeatus)
In the years since Tinburgen's study of the threespine stickleback, most exploration has centered on visual aspects of this animal's sensory world. Consequently, very little is known about the underwater sounds made by this fish or the behavioral implications of such noises. Considering that few animals rely solely on one sense for the transmission of information, it is important to investigate all sensory systems of a species. Acoustically, perhaps the most predominate of all noises made by sticklebacks is the incidental noise created when an aggressive male bites another stickleback. Sounds during attacks in male/male and male/female interactions were recorded with a hydrophone connected to a Dell® Inspiron 7000™ computer using Microsoft® Sound Recorder™. These metallic clanging sounds were then analyzed using a Gram 50 sound analysis program. A second setup employed the same hydrophone connected to a video recorder for simultaneous video/audio evaluation. This was necessary to confirm that sounds recorded on the computer were indeed associated with biting. Layers of Styrofoam, wood and foam were placed under the hydrophone stand and the test tank to prevent substrate vibrations from interfering with any fish-generated sounds in the water. Bite sounds from 4 male/male and 10 male/female interactions were analyzed for peak frequency, duration and loudness. There was no significant difference in sounds during male/male interactions and male/female interactions in terms of peak frequency (ÿ Å SD = 1135 Å 321.3 Hz) or duration (33.6 Å 11.34 msec.) for both groups. However, a t-test revealed a difference (P = 0.047) between the intensity of bite sounds during male/male (8.5 Å 2.89 dB) and male/female (14.3 Å 4.83 dB) interactions . These results suggest that biting intensity is less when males engage other males than when they engage females. Further investigation is necessary to determine if these biting sounds serve any communicative function among sticklebacks.
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2001 REU Mentor: Dr. William J. Rowland & Richard Granquist, Department of Biology (Rowland lab)

Male-to-Male Mating Competition in the Broad-Horned Flour Beetle, (Gnathocerus cornutus)
Sexual selection often favors the production of colorful ornamentation or weapons used to attract or defend mates. Many species of beetles produce horns. Though they vary in size, shape and location on the body, beetle horns seem to be used primarily for male-to-male competitions for access to females. Males of the species Gnathocerus cornutus produce a pair of mandibular horns. During this study I observed G. cornutus males using the horns to: ram other beetles, dismount males attempting to mate, flip opposing males onto their backs, grasp and carry opposing males around the mating arena. The focus of my study was whether or not large horns confer increased mating opportunities. Each contest was conducted in a 22.5mm arena lined with filter paper, and consisted of a large horned male, small horned male and a female. I videotaped competition for one hour in a darkened room using red lights. The start and end times of mounting were recorded for each male. The winners of aggressive male-to-male encounters were also recorded. Our results suggest that although large horned males do not win more fights, they had longer access to females. This may be due to the fact the large males typically asserted their dominance with fewer encounters, while some smaller males repeatedly fought throughout the trial.
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2001 REU Mentor:  Dr. Michael Wade & Jeff Demuth, Department of Biology (Wade lab)

Behavioral Evaluation of Ascorbate-Treated Transgenic Mice Carrying the Human Huntington's Disease Mutation
Huntington's Disease (HD) is a dominant autosomal, neurodegenerative disorder with symptoms that include depression, dementia, and chorea. HD is caused by the gene IT15 located on the human fourth chromosome. In HD patients, the 5' end of the IT15 gene has more than thirty-seven repeating copies of the CAG trinucleotide. The number of repeating codons determines the age of onset of the disease; however, onset of the disease for most patients is between the ages of thirty and fifty. Transgenic mice with the human HD gene have been developed to facilitate understanding and treatment of the disease. Using strain B6CBA-TgN [HDexon1] 62Gpb, behavioral evaluations were made implementing a series of protocols once a week from the ages of six to ten weeks. Five out of the nine HD mice were given ascorbate (AA, 300mg/kg), while the remaining four were given equivolume saline. The first of the series was an open arena in which each mouse was taped for fifteen minutes. Later the videotapes were reviewed to determine the number and time period of each behavioral incident (locomotion, sniffing, climbing, jumping, rearing, grooming, digging, crawling, and resting). Subsequently, an ethogram was created. HD mice receiving AA reared on an average twice as long as the HD mice receiving saline (p=0.03). HD mice receiving AA tended to spend less time grooming and more time climbing than vehicle-treated HD mice (p=0.11 and 0.16, respectively). The activity box (an open area divided into four quadrants) was the second apparatus of the series, and each mouse was allowed unrestricted movement for ten minutes. Each square entered was recorded. AA HD mice tended to be more active than the saline HD mice totaling almost twice as many square crossings in a ten minute session for the first and second weeks of taping, though the difference was not statistically significant. Overall, the data suggest that vitamin C treatments result in HD mice that are more active than those without treatment.
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2001 REU Mentor: Dr. George Rebec & Scott Barton, Department of Psychology/PNS (Rebec lab)

Embryonic Effects of Testosterone Treatment on Japanese Quail Eggs
Testosterone is a steroid hormone that has a variety of effects on animal behavior, physiology and morphology. Recent studies have indicated that testosterone present at the beginning of development can have behavioral and growth effects that persist into juvenile and adult life stages. These studies suggest that initial testosterone levels affect embryo development, however few studies have explored these effects. We experimentally tested the effects of testosterone on embryonic growth and metabolism by injecting unincubated Japanese quail eggs with testosterone. We predict that elevated testosterone levels would increase embryo metabolism and growth resulting in a decrease in incubation period. Metabolic rates, which we measured in a closed system, were estimated by measuring the rate of oxygen consumption (VO2) of each egg throughout incubation. We detected no effect of testosterone treatment on metabolic rate, growth or incubation period. The peak metabolic rate averaged 7.9 mL/hr prior to hatching and incubation periods averaged 20.4 days. At hatching, chicks weighed 7.40g on the average, 18.5% of this mass was tissue and 4.1% was residual yolk sac. With the wide-spread effects of testosterone on phenotype, it is critical that we understand how variation in testosterone levels impact embryonic growth and development, and how this could further affect a cascade of ontogenetic changes. Testosterone and its effects on embryonic growth, development and its continuing effects on adult life remains an important topic that warrants further research.
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2001 REU Mentor:  Dr. Ellen Ketterson & Dr. Wendy Reed, Department of Biology (Ketterson lab)

Variation in the Push-up Displays of the Sagebrush Lizard, (Sceloporus graciosus)
Many animals are found to modify their social behavior patterns over time when confronted with new social situations. For example, some male song sparrows modify their communicative displays to match the songs of their neighbors. In this study, we examined whether or not individual lizards also change the displays used during social interactions over long periods of time. Specifically, we compared the push-up displays of individual Sceloporus graciosus on two different dates (early and late) to determine 1) if individuals change their displays over time and 2) if they do change, do they become more similar to animals around them. Sex had a significant effect on the frequency of displays with males displaying about twice that of the females however, sex did not affect the structure of each individual's push-up display pattern. Individuals can and do modify their display patterns over time. Early in the study, individuals displayed more frequently. Displays were also longer and consisted of more head bobs per display. However there was little, if any, evidence that animals modified their displays to match those of their neighbors.
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2001 REU Mentor:  Dr. Emilía Martins & Heather Bleakley, Department of Biology (Martins lab)

Influence of Testosterone in ovo Treatment on Sprint Speed of Japanese Quail (Coturnix japonica) Chicks
In addition to genes, the developmental environment influences offspring phenotype. Testosterone deposited in the egg yolk by avian females is one example of a maternal environmental contribution that has been demonstrated to have both positive and negative effects on offspring performance, survival and aggression. In particular, maternally derived testosterone has been shown to increase muscle growth in offspring. We, therefore, asked whether experimentally elevated levels of testosterone in the yolks of Japanese quail (Coturnix japonica) eggs influence the sprint speed of offspring. Eggs were treated with 100 ng testosterone in 70% ethanol (T2), 15 pg/mg yolk testosterone in 70% ethanol (T1) or ethanol only (C). Sprint speed was measured using a one-meter racetrack automated to record velocity. Chicks ran towards cage mates in two trials (three runs per trial with a 20-second rest between runs and a two-hour break between trials) and 24 hours later, towards an empty shelter while chased with the experimenter's hand. When running towards cage mates, T1 chicks had a significantly lower sprint speed than either C or T2 chicks. However, when chased, the three treatment groups did not differ in sprint speed. Our results suggest that whereas relatively large increases in the testosterone level in the eggs of Japanese quail may not influence sprint speed, smaller scale changes in testosterone may decrease sprint speed motivated by social interactions. This unpredicted result may be a consequence of low levels of testosterone decreasing sociality and higher levels increasing aggressive social interactions. Experiments designed to measure aggression and sociality in chicks need to be conducted to test these ideas.
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2001 REU Mentor:  Dr. Ellen Ketterson & Jennifer Grindstaff, Department of Biology (Ketterson lab)

Female Choice in the Sailfin Molly (Poecillia latpinnia)
A goal of sexual selection theory is to explain the conspicuous secondary sexual traits of males throughout the animal kingdom. Previous research has shown that female sailfin mollies (Poecilia latpinnia) prefer males of larger sailfin size and body size. However, it is unknown whether the preferences are for these characters specifically, or whether selection on the two traits is the result of a general preference of females for males with increased lateral projection area (LPA). This study investigated the relative roles of male body size, sailfin size and overall LPA in female choice in P. latipinna. Females were tested using a previously established protocol involving simultaneous presentation of male dummies varying in sailfin to body size ratio, while controlling for overall LPA. Pair-wise t-tests revealed no significant preferences for any of the five male stimuli. These results suggest that preferences for sailfin and body size may be a byproduct of a more general female preference for increased LPA which may, in turn, enhance stimulation of the female's visual system.
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2001 REU Mentor:  Dr. William Rowland & Dave MacLaren, Department of Biology (Rowland lab)

Development of Preference in a Foraging Situation
Research on choice behavior has primarily dealt with looking at behavior at a steady-state, where no more systematic changes are being observed. It is not understood how the animal comes to prefer one alternative over another or whether or not it will choose the richer of the two. Development of a preference for the richer of two alternatives would greatly benefit the animal by providing more food. Our purpose was to look at how development of preference occurred. We ran two experiments varying the total probability of reinforcement as well as the difference independently. The procedures used allowed us to precisely alter the probability of reinforcement. This enabled us to test the predictions of our model, dP/dt=   x T (D/T)F x P(1-P). This model includes a Weber Law-like ratio (D/T) that proposes that larger differences and smaller totals lead to an increase in ability to discriminate foraging alternatives.
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2001 REU Mentor:  Dr. Rich Keen & Eric Macaux, Department of Psychology (Machado lab)

Effects of Age, Memory Type, and Alcohol on Learning and Persistence in Rats
Previous research has found conflicting results as to the effect of alcohol on persistence. Baer, et al (1995) found that children of alcoholics are significantly less persistent than controls on problem-solving tests due to sustained attention requirements. However, Heyman (1997) found that rats persisted in responding when given alcohol plus saccharin even when the work requirement was increased. This study uses a Morris Water Maze to determine how age, memory type (working vs. reference), and alcohol dose affects learning and persistence in rats. Two doses of alcohol were used (0.5 and 1.0 g/kg) and were compared against saline. Working memory rats had a different home platform (HP) location across days, whereas reference memory rats had the same HP across days. Each rat had 8 days of training to the HP (4 trials/day), followed by four test days. On test days the rats received injections of either saline, 0.5 g/kg of alcohol, or 1.0 g/kg of alcohol. Trials 1 & 4 of each test day measured drug effects on learning by the latency to swim to the location of the HP. Trials 2, 3, & 4 measured persistence in swimming in the same quadrant in which a platform was previously located. Acquisition results showed no effects of type of memory or age of rat on rate of learning. Alcohol dose on test days appeared to interfere with reference memory, but not with working memory and appeared to have no consistent effect on persistence.
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2001 REU Mentor:  Dr. William Timberlake & Joe Leffel, Department of Psychology (Timberlake lab)

Origins of Social Organization in Cowbirds (Molothrus ater)
Recent work from the West and King lab indicates that the social experience of flock mates affects behavioral development of juvenile cowbirds. No work has been done, however, to study how social dynamics in a flock affect very young cowbirds. I designed a study to discern if the presence of socially experienced conspecifics (adults) could influence the behavior of juveniles within a flock. I set up two conditions in aviaries. Both conditions held juvenile birds, and one also held adults. I collected nearest-neighbor measures and song data from both aviaries. Different social structures emerged rapidly in the two conditions. There were more juvenile near-neighbor associations where adults were present then where adults were absent. I also found that juveniles sang significantly less in the presence of adults. This study reveals that social organization of cowbirds originates early in development. Furthermore, the company of adults significantly affects social organization and vocal behavior of juveniles, providing them opportunities for learning through social interactions.
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2000 REU Mentor:  Dr. David White & Dr. Meredith West, Department of Psychology (West / King lab)

Copulatory Courtship of Wild and Mass-Reared Caribbean Fruit Flies (Anastrepha suspensa)
Video recordings of the copulation behavior of two different wild and one mass-reared population of the Caribbean Fruit Fly (Anastrepha suspensa) (Tephritidae) in captivity reveal expected differences as well as some hitherto unreported details. As expected, differences between one of the wild populations and the mass-reared population were seen in copulation duration; the wild population mated for a significantly shorter period. Surprisingly, the second wild population, which was the second generation in the lab, showed behaviors and copulation duration more similar to mass-reared flies than the other wild population. A trend was seen, for example, in the location of male palpations on the female. The second-generation wild population and the mass-reared flies palpated predominately on the top of the head while the "true" wild population palpated on the females' antennae. Another unreported behavior is the presence of trophallaxis, the female consumption of fluid provided by the male. These results may have important implications for programs attempting to control fruit fly pests and for our understanding of sexual selection.
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2000 REU Mentor:  Ann Fritz, Department of Biology (Rowland lab)

Maternal Stimuli Mediate Activity in the Newborn Rat
Past studies have found that the maternal odor of amniotic fluid and birth membranes are vital cues for suckling in newborn rats (Pederson & Blass, 1982; Teicher & Blass, 1977). In addition, maternal tactile stimuli may also be an important cue. The purpose of the present study was to systematically assess the role of olfactory and tactile maternal stimuli in the expression of antecedent behaviors to suckling. Eighty-four gestational-day-21 perinates from female Sprague-Dawley rats (Rattus norvegicus; 80-100 days), bred in the Indiana University colony, were subjects for this experiment. On gestational day 21, pregnant females were anesthetized, and the uterine horns were externalized into a temperature-controlled saline bath. Compressions designed to simulate natural contractions experienced during labor were administered to adjacent fetuses (positions 2, 3) in each uterine horn. Following caesarian delivery, newborns were brushed to simulate the maternal licking of the membranes establishing respiration. Afterwards, the simulation of natural temperature exposure stimulated the newborns. The newborns were tested under the following conditions: odor/fur, odor/no fur, no odor/no fur; and no odor/fur. Their behavior was videotaped for 10 minutes. Time spent prone with the snout in contact with substrate and general activity were measured. Fur was found to have a significant effect on snout contact, and odor had a significant effect on general activity. Additionally, the interaction between fur and odor was found to have a significant effect on general activity.
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2000 REU Mentor:  Jill Menge &Dr. Jeffrey Alberts, Department of Psychology (Alberts lab)

Developmental Assessment of the Transgenic Mouse Model of Human Huntingtons Disease: An Evaluation of Behavioral Phenotype
Huntington's Disease (HD) is a late-onset progressive neurodegenerative disease caused by a dominant genetic mutation in which an expanded CAG sequence is present within the coding region of a gene residing on human chromosome four (Carter et al., 1999). The disease is characterized by motor abnormalities and impairments, cognitive deficits, and dementia that progress towards death (Hodgson et al., 1999). A transgenic mouse model carrying the CAG repeat exon of the human Huntington gene has been developed and has been reported to exhibit many of the symptoms of HD (Carter et al., 1999). In order to complete a full behavioral assessment of this animal model, mice heterozygous for the HD mutation and controls of the same strain were videotaped for two 15-minute sessions per week from ages 5-10 weeks in an open-field container. A kinematic behavioral ethogram was developed and total activity, behavioral variability, and time engaged in particular behaviors were assessed. Results indicate that HD mice have significantly reduced activity levels based on a total number of behaviors as well as fewer distinct behaviors when compared with controls (p < .001). Although the activity levels in HD mice generally decline with age (p < .10), there is considerable variation in the total amount of behaviors engaged in within the particular ages of HD mice. This finding suggest that this mouse model does progressively develop behavioral symptoms of HD, but the rate of this development is variable.
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2000 REU Mentor:  Scott Barton & Dr. George V. Rebec, Department of Psychology | Program in Neural Science (Rebec lab)

Biospecimen Testing for Subsystem Design of the Advanced Animal Habitat-Cetrifuge (AAH-C)
The International Space Station (ISS) is a revolutionary laboratory and operational collaboration of 16 nations. Aboard the ISS, the Centrifuge Accommodation Module (CAM) will house a 2.5M Centrifuge Rotor (CR) that will provide a variety of gravitational forces up to 2G. A variety of research will be conducted using the CR, such as developmental biology and systems and comparative biology. The Advanced Animal Habitat-Centrifuge (AAH-C) will provide housing for both rats and mice from PN-21 to adulthood for up to 90 days of space flight in the CAM. In preparation for these experiments, preliminary studies have been reformed focusing on mouse metabolism, effects of airflow, and maximizing environmental enrichment to aid in subsystems design of the AAH-C. The purpose of the mouse metabolism study has been to measure the food and water intake and urine and feces output of mice when given NASA-formulated Rodent Food Bar (RFB). Subjects included four each of 20g and 40g male ICR mice, individually housed. In a metabolism chamber, mice acclimated for two days, and data were collected on days three and four. The purpose of the airflow test has been to distinguish an impact of continuous airflow (0.3m/s) on the metabolism of rats by measuring body weight, and food and water intake. There is group housing of six rats in each of the six airflow and control (ambient air circulation) chambers, and data is taken on days seven, nine, eleven, and thirteen, after six days of acclimation. 100g females Sprague-Dawley rats were subjects of the initial testing; 100g male, 250g male and female, and 450g male rats will follow in future studies. Until all studies are completed, data can be measured not reported. Lastly, the purpose of the environmental enrichment study has been to further assess tactile- retreat stimulation and thigmotaxicity using open space cages as a baseline. Time-lapse videography are scored for huddling behavior and snout location of 100g, 250g, and 450g male and female Sprague-Dawley rats. Thus far, acclimation studies have been completed, and the full- study data collection is underway.
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2000 REU Mentors:  Sherry Lifer, Mark Coleman, Rod Ginter, & Dr. Jeffrey Alberts, Department of Psychology (Alberts lab)

Maintenance of Crystallized Adult Song in Northern Cardinals Requires Auditory Feedback
Auditory feedback is necessary for song learning by young birds but has been assumed not to be required after song crystallization in adulthood. However, Nordeen and Nordeen (1992), Okanoya and Yamaguchi (1997), have found that some adult songbirds show deterioration in their crystallized songs as the result of being deafened. The cardinal, Cardinalis cardinalis, like the majority of the species examined, is a critical-period learner, which maintains the same songs throughout adulthood. To find out whether adult cardinals require auditory feedback to maintain their songs, I used computer sound analysis software (SAS Lab and SIGNAL) to compare the songs of two adult birds before and after deafening. One cardinal was observed for 5 weeks after deafening, and the other was for 13 weeks after deafening. The birds were deafened by removal of both cochleae. Acoustic properties of the syllables of each bird were examined. Syllable repertoire did not change, but the structure of some syllables did alter. Deterioration in song for one cardinal included an increase in the duration of one syllable and a decrease in its ability to control the fundamental frequency of seven syllables, which was determined by the change in the morphology of the syllables. The other bird showed a decline in the fundamental frequency of one syllable and an increase in the duration of two syllables. This suggests that over time even adult crystallized song may gradually deteriorate in the absence of auditory feedback.
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2000 REU Mentor:  Dr. Roderick A. Suthers & Sue Anne Zollinger, Department of Medical Sciences (Suthers lab)

Honest Signals: Does Fatigue Affect Aggressive Displays in Siamese Fighting Fish?
Aggressive behavior typically occurs when two conspecific males confront each other and compete for territory, mating opportunities or social status. In confrontations between two Siamese Fighting Fish, Betta splendens, males perform threat displays, which may escalate to physical attacks. These threat displays consist of alternately orienting the body between a frontal to a lateral position while extending the dorsal, caudal and anal fins. Furthermore the gill covers (opercula) and the branchiostegal membrane may or may not be erected. Evolutionary biologists suggest that such displays are honest signals and accurately reflect the condition and fitness of the displayer, i.e. the more fit individual can perform more aggressive displays for a longer period of time. If this is so, then fatigued animals should display less or differently. I tested this hypothesis by placing males in an underwater chamber and allowing them to view a conspecific opponent or a mirror image both before and after subjecting the males to a water current. Because Siamese fighting fish normally live in stagnant pools, a water current should fatigue the fish. When comparing before- and after-current displays, I found that fatigued fish exhibited a significantly lower amount of threat displays than non-fatigued fish. This is consistent with the idea that aggressive displays of these fish are honest signals that reliably reflect their physical condition. Further testing will help to confirm that the change in aggressive behavior is due to fatigue in the male and not to fear that might have been elicited by the water current.
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2000 REU Mentors:  Dr. William J. Rowland & Yoni Brandt, Department of Biology (Rowland lab)

Are There Sex Differences in Dietary Composition and Activity Budget of Mantled Howler Monkeys (Alouatta palliata)?
At one time it was assumed that, because howler monkeys (Alouatta palliata) have among the most folivorous diets of all primates, there would be little competition between individuals, few differences between age-sex classes, and little food-item selectivity. The work of Milton (1979, 1980, 1982, 1984) demonstrated that rather than being unselective, howler monkeys actually reject much potential food, and that food items they do select are quite different than foods they reject. Milton, however, paid little attention to sex difference. Females are burdened with gestation costs, infant care costs, infant carrying costs, and lactation costs. Because of these added strains, they might be predicted to be more selective than males. On the other hand, their social rank is lower than that of males, so they may be forced into utilizing low-quality foods due to competition. I observed howler monkeys in a tropical lowland wet forest in Costa Rica and examined sex differences in activity budget and dietary composition in an attempt to determine whether there were differences between the sexes in diet and/or activity budget. I also attempted to determine whether diet differences were caused by females being lower ranking or because of the added stresses of offspring care. However, due to a very minimal sample size, the results that I obtained were found to be statistically insignificant. In order to obtain more significant results, a longer amount of time would be needed to conduct this research and the study would need to be conducted throughout the year because fruiting and flowering were minimal at the time my study was conducted which caused the howler diet to be very limited.
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2000 REU Mentor:  Kim Dingess, Department of Anthropology (Hunt lab)

The Effects of Testosterone and Food Coloration on Response to Novelty in the Male Domestic Chick (Gallus gallus domesticus)
Testosterone has been shown to have many diverse effects on male birds, both behaviorally and physiologically. Based on studies of the domestic chick (Gallus gallus domesticus), Andrew (1972) hypothesized that high testosterone causes males to focus more rigidly upon stimuli that are relevant to an entrained task. Jones and Andrew (1992) compared response to novel stimuli in roosters and capons and found that when familiar yellow food are replaced with unfamiliar blue food, the higher testosterone roosters are more distracted by this change than are lower testosterone capons. It has been suggested that chickens have a natural aversion to blue foods. The stabilization of attention hypothesis was tested using an experiment similar to that of Jones and Andrew, by comparing the responses of testosterone-treated and control chicks to novel food colors (blue and red). The chicks' responses in both test conditions were compared to determine whether the birds showed more aversion to blue food than to red, and to determine whether testosterone's effect on response to novelty (if any) was influenced by color. In both testosterone-treated chicks and control chicks, unfamiliar blue food caused significantly greater aversive responses than unfamiliar red food. No differences in response to novelty occurred between testosterone and control chicks, regardless of the novel color. The hypothesis that chicks have stronger aversive responses to blue as a novel stimulus than to red was strongly supported. However, the data did not support the stabilization of attention hypothesis.
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2000 REU Mentor:  Martha Bowman, Department of Biology (Phillips lab)

Direct, but Not Indirect, D1 Activation Facilitates Efficient Search of an Unbaited Radial Arm Maze
By using indirect and direct D1 manipulations, Tinsley, Rebec and Timberlake (in press) were able to increase the frequency of an unconditioned preparatory behavior -- ball bearing contact -- in rats. To examine the generality of these effets, Tinsley (unpublished) used the same direct D1 agonist, SKF81297, on a second unconditioned preparatory behavior, search of an unbaited radial arm maze. This treatment resulted in increased search efficiency. Following these results, we tested the ability of the indirect treatments used by Tinsley et al. to produce the same effect on maze behavior as SKF81297. We found that injections of neither the D2 antagonist eticlopride nor the indrect D1/D2 agonist amphetamine significantly increased search efficiency. These results indicate that despite ball bearing contact and efficient maze search behavior are both unconditioned preparatory behaviors, they are differentially affected by dopamine treatments. These results highlight the importance of the experimental procedure in the examining effects of dopamine manipulations and may suggest different neural substrates for these behaviors.
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2000 REU Mentor:  Dr. William Timberlake & Matthew Tinsley, Department of Psychology (Timberlake lab)

The Effects of the Developmental Environmenet on Antipredator Mechanisms of Larval Southern Two-Lined Salamanders, Eurycea cirrigera
Antipredator mechanisms are employed by animals to reduce their probability of being seen, chased, captured, and then consumed by their predators. Larval southern two-lined salamanders (Eurycea cirrigera) enhance their survival by employing several antipredator mechanisms. One such trait is crypsis, which is the ability of an animal to look like part of its environment. Larval Eurycea are able to facultatively change their dorsal coloration in response to external cues, perhaps allowing them to better "match" a number of substrates encountered in the environment. Other compensating antipredator mechanisms potentially used by larval Eurycea include seeking refuges under rocks and other stream debris and choosing to be more active at night rather than during the day, when visual predators are expected to be a greater threat to their survival. Larval E. cirrigera may acquire a different combination of these traits depending on their developmental environment. Certain combinations of antipredator mechanisms reduce the risk to larval Eurycea of becoming prey to predators as the larvae forage in the streams or drift downstream to new environments.
     We conducted four experiments to determine how the rearing environment affected the expression of antipredator mechanisms in 29 larval E. cirrigera. Larvae were randomly assigned to one of three rearing environments: black sand, white sand, or a variable substrate (white substrate alternated with black substrate every 5 days). Larvae were raised on these substrates for four weeks prior to testing. Our first two experiments examined how the rearing environment affected the extent of color change possible by larval E. cirrigera and the length of time that was needed for maximal short-term color change. We also conducted a habitat preference experiment that examined whether the larval rearing environment resulted in a preference by larvae for a particular background color or for the use of refuges when placed into new environments. Preliminary results indicate that the rearing environment does not affect where larvae go when placed into a new environment. In general, larvae prefer the black substrate to the white substrate. Larvae did not prefer to hide under cover objects within the first 2 minutes in a new location. Our final experiment determined whether larvae were most active during the day or at night, and whether the rearing environment affected activity level patterns in larval E. cirrigera. Preliminary results indicate that larvae are more active at night than during the day, regardless of rearing environment. The results from all four of our experiments indicate that the developmental environment may play an important role in determining mainly the color changing ability of larval E. cirrigera.
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1999 REU Mentor:  Stephanie Welter, Department of Biology (Brodie lab)

Glucocorticoids Impair Memory for New Food Locations During Later Stages of Food Stress
Previous research has shown that (a) sudden food reductions increase circulating corticosterone, and (b) that glucocorticoids may be involved in the modulation of memory for emotional events and spatial locations. This experiment tested the effects of the glucocorticoid receptor (GR) antagonist RU 38486 on memory for a new food location following periods of food stress. Two groups of intracerebroventricularly (i.c.v.) cannulated male rats were run in a successive contrast procedure on an eight arm radial maze. Each group received 32% sucrose solution in a fixed arm of the maze once daily for 15 days. They were then downshifted to a 4% solution for two days to promote food stress and an adrenal response. On the next day they received the 32% solution in a novel location. One group was given the GR antagonist i.c.v. when the 32% solution was available in the new location, whereas the other 32% solution group received saline i.c.v.. The following day they were tested for their memory of the new location. The group given RU 38486 made fewer errors finding the new location on the day following the upshift than did the 32% saline group. These results suggest that stress levels of glucocorticoids impair memories for new spatial locations, at least in the latter days following a food downshift.  |CURRENT INFO|

1999 REU Mentor:  Norman C. Pecoraro, Department of Psychology (Timberlake lab)

Subtle Features of Female Body Posture as a Cue for Male Courtship in the Threespine Stickleback,Gasterosteus aculeatus
Female threespine sticklebacks use a number of visual signals to exhibit receptivity and apparent fecundity to courting males. When presented with a choice of two dummy females, males have been found to prefer: 1) increased abdominal distention indicating the presence of mature ova, 2) a dark mottled banding pattern that develops in sexually receptive females, and 3) a unique body posture that females assume during courtship. This study focused on the posture cue in which receptive females assume a head-up position and raise their tail to give their back a concave shape, a posture referred to as lordosis. I tested whether males would differentially court females exhibiting lordosis relative to females in which the lordosis posture was absent. Nested male threespine sticklebacks were simultaneously presented with two epoxy castings of females exhibiting a 45% head-up position and identical color and degree of abdominal distention. One dummy exhibited a straight back whereas the other exhibited the concave lordosis posture. Males spent more time at the lordosis dummy and directed more courtship (zigzags) to it, but aggressive behavior (bites) was distributed evenly between the two dummies. Thus, male threespine sticklebacks discriminate between subtle differences in female body shape, showing a preference for the lordosis posture. This response is appropriate if females exhibiting this posture have greater sexual receptivity than females who do not exhibit this posture.  |CURRENT INFO|

1999 REU Mentors:  Dr. William J. Rowland & Dave MacLaren, Department of Biology

Combining Positional Behavior with Labanotation in Bonobos and Gorillas
This project seeks to incorporate Labanotation in the study of primate positional behavior (i.e., postural and locomotor behaviors). Labanotation, devised by Rudolf Laban in 1928, has been used previously as a system of recording human movements. This system uses a defined set of symbols that are modified from a default rectangle. Each modification of shape, length, and shade indicates changes in direction, duration, and level of movement, respectively. The language-like nature of this movement notation promotes a range of diversity with which different types (e.g., dance, athletics, occupational) and styles (e.g., ballet, ballroom, cultural) of movements can readily be depicted.
     We made several modifications to the previous notation (Hutchinson, 1954). This allowed us a proficient means to record primate postural and locomotor behaviors. Such modifications include altering the order of body segment columns, dividing support into forelimbs and hindlimbs columns, and adjusting levels of trunk orientation. Although Labanotation is seldom used outside choreography, it holds great promise for animal behaviorists, especially those with interests in postural and locomotor behaviors. The Laban system records complicated movements in a precise and economical manner. Current methodology in primate positional behavior is not equally precise. Also, current methodology in primate positional behavior is not as open-ended as is Labanotation. This difference allows Labanotation to process novel and innovative behaviors more efficiently than is currently possible. In general, Labanotation will be applicable beyond the Order Primates. Thus, animal behaviorists studying organisms besides primates will benefit from this methodology for similar reasons.
     In our study, we emphasized the use of the Laban system with primates in the Cincinnati Zoo, specifically bonobos (Pan paniscus) and western lowland gorillas (Gorilla gorilla gorilla). We chose apes because of their close affinities to human anatomy, large body size, high degree of terrestriality, and relatively slow activities. Positional behavior was quantified following the instantaneous and focal animal strategies outlined by Altman (1974). We compiled data over a three-month period covering various hours of the day (e.g., 9am - 7pm). Upon the conclusion of our study we will present a standardized and detailed methodology of notation that will provide additional information regarding intraspecific and interspecific behavioral comparisons within and between primate species. Through the insightful use of Labanotation and positional behavior intricate connections between behaviors of modern animals and of their predecessors may be revealed.  |CURRENT INFO|

1999 REU Mentors:  Dr. Kevin Hunt & Kristian Carlson, Department of Anthropology

The Effect of Chemosensory Predator Cue on Morphological Characters and Escape Behavior in Hyla chrysocelis Tadpoles
Anti-predator strategies play an important role in the life history of larval anurans in aquatic communities. The ability to recognize chemosensory stimuli produced by predators is often an important component of anti-predator strategies. Responses to these stimuli, or predator cues, can play an significant role in initiating predator avoidance behavior or stimulating morphological development. Previous studies have shown that gray treefrog (Hyla chrysocelis) larvae exhibit both behavioral and morphological responses to chemical cues from a variety of predators. In southern Indiana, larvae of Jefferson's salamander, Ambystoma jeffersonianum, are the primary predators of gray treefrog tadpoles. A. jeffersonianum are gape-limited predators. Consequently, the susceptibility of gray treefrog tadpoles to predation changes through ontogeny. This experiment examined the effects of a chemosensory predator cue on tadpole morphology and escape behavior through the course of development. Tadpoles were collected in the field between June 4-6, 1999; 108 tadpoles from nine clutches were randomly assigned to 1 of 4 treatment groups in a 2x2 factorial design (cue/filmed, cue/not filmed, no cue/filmed, and no cue/not filmed). Tadpoles were raised individually in 16 oz. cups. The cue group received 4 ml of salamander-cued water every three days; there was no direct contact between tadpoles and salamanders. Filmed tadpoles were placed in an arena where swimming behavior, in response to a simulated predator attack, was recorded via digital video system. Beginning nine days after hatching, morphology (for all groups) and escape behavior (for filmed groups only) were recorded every 9 days until metamorphosis. Black-and-white digital images of each individual were measured using Scion Image software and body length, tail muscle width, tail length, and fin height were recorded from each image. Analysis of variance was used to examine the effects of treatment and time on morphological characters. Results show that body length and tail length were not affected by treatment. However, tail muscle width and fin height were significantly different between treatment groups. Treatment by time interaction was not significant for any of the characters, however, tail muscle width showed a trend for a change in the effect of treatment through development. The escape sequences were not included in the preliminary analysis, but three components of escape behavior will be analyzed: burst speed, number of turns, and angles of turns in an escape sequence. While treatment did not affect all of the characters measured, tail muscle width and fin height are important morphological components of swimming behavior. Therefore, it appears that tadpoles respond to chemosensory signals of predator proximity and alter the development of particular structures involved in anti-predator escape behavior.  |CURRENT INFO|

1999 REU Mentor:  Cerise E. Allen, Department of Biology (Brodie lab)

Laugh Away Your Cravings: The Effects of Nitrous Oxide on the Drinking Behavior of High Alcohol Drinking and Alcohol Preferring Rats
Early studies have shown nitrous oxide to be effective in treating alcohol withdrawal in humans. Its use has been shown to be effective in suppressing the intense craving that occurs in the first few months after withdrawal, helping the subject to continue abstinence. In this study we wanted to establish an appropriate animal model to study not only the mechanism and effectiveness of nitrous oxide-induced-drinking suppression but also to see if this phenomenon was observable under laboratory conditions. Male high alcohol drinking (HAD) and alcohol preferring (P) rats underwent a period of forced drinking followed by 1 hour per day free-choice access to a 10% ethanol solution. Once stable drinking levels were established, the 16 highest drinking rats (8 HAD/8P) were exposed to a 75%/25% nitrous oxide/oxygen mixture for 30, 60, 120 minutes, or oxygen alone for 120 minutes. Gas exposures occurred every 4 days. These exposures were scheduled so they always ended one hour before the established hour of ethanol access. Consistent with earlier results in humans, nitrous oxide suppressed ethanol drinking in rats in a dose-dependent manner. A small decrease in ethanol drinking occurred with oxygen exposure while water consumption was not affected by any gas treatment. These results confirm the ability of nitrous oxide to selectively suppress alcohol drinking, thus establishing a rat model appropriate for use in studying the basic mechanisms underlying this effect.  |CURRENT INFO|

1999 REU Mentors:  Dr. Ann Kosobud & Dr. George Rebec, Department of Psychology

Reproductive Character Displacement in the Calling Songs of Two Cricket Species, Gryllus fultoni and G. vernalis (Orthoptera; Gryllidae)
Reproductive characters may exhibit greater differentiation in areas where two species overlap (areas of sympatry) than in areas where they occur separately (areas of allopatry). This differentiation is known as reproductive character displacement and is hypothesized to have evolved as a response to reduced hybrid fitness between closely related species. To test for reproductive character displacement, we investigated variations of calling song characters among sympatric and allopatric populations of two cricket species, Gryllus fultoni and G. vernalis (Orthoptera; Gryllidae). These two species inhabit wooded areas and occur in sympatry in an area that ranges between southern Indiana and Tennessee. G. vernalis occurs alone north of the sympatric area, whereas G. fultoni is found alone south of the sympatric area. Calling songs were recorded from five locations encompassing sympatric and allopatric populations of both species. The calling songs were analyzed to find the following characters: pulse rate, chirp rate, pulse length, and peak frequency. Sympatric G. fultoni populations were found to have significantly higher pulse rate, chirp rate, and peak frequency than allopatric G. fultoni populations. There were no significant differences in calling song characters between sympatric and allopatric G. vernalis populations. This suggests that reproductive character displacement has occurred in the evolution of the song characters of G. fultoni, but not in those of G. vernalis.  |CURRENT INFO|

1999 REU Mentor:  Dr. Yikweon Jang, CISAB & Department of Biology

Diet Does Not Effect Mate Choice in Japanese Quail
The protein requirements of Japanese quail (Coturnix coturnix) for laying and breeding periods are 17% and 20% of their diet respectively. Deficient quantities of amino acids can impact nutritional status. For example, Bobwhite quail (Colinus virginianus) hens had increased egg production, size, and mass on high-protein diet (21%) whereas low-protein diet (12%) birds had significantly decreased fertility. Little is known, however, about the effect of diet on avian mate choice. To better understand the effects of dietary condition on sexual selection, the mate choice of female Japanese quail was studied subsequent to maintenance on varying dietary protein levels. Male and female quail were placed on high (20%) or low (10%) protein diets for a minimum of 7-14 days before testing. One female from each diet group was simultaneously presented with one high-protein diet male and one low-protein diet male for 12-minute trials. If females laid eggs less than 4 days per week, they were excluded from testing. Males were rated on four factors: mass, wing length, tarsus length, and plumage condition.
     Factor scores were averaged to produce a "quality factor" (Q.F.), and high-protein males were paired with low-protein males according to closeness in Q.F. Subjects were given two minutes to habituate to testing apparatus and for females to notice both males. Female position was then videotaped for 10 min. The test apparatus consisted of three chambers: a left chamber (30 cm wide) containing one stimulus male, a central chamber (90 cm wide) containing the subject female, and a right chamber (30 cm wide) containing the other stimulus male. A male was considered preferred if a female spent more time within 30 cm of one male than within 30 cm of the other male. Fourteen females were tested against 12 pairs of males in a total of 22 trials; a given female + male pair was not used more than once.
     Females preferred high-protein diet males in eight trials and low-protein diet males in ten trials. Thus no correlation between protein diet and sexual preference was found, suggesting protein-dependent condition does not affect female mate choice. However, limited sample size may have influenced such findings.  |CURRENT INFO|

1999 REU Mentor:  Jennifer Grindstaff, Department of Biology (Ketterson lab)

The Effects an NMDA Antagonist, MK-801, During Development on Motor Neurons in the Spinal Nucleus of the Bulbocavernosus
The spinal nucleus of the bulbocavernosus (SNB) is sexually dimorphic group of motor neurons. Development and maintenance of the SNB are influenced by changes in androgen levels (Goldstein et al., 1990). The N-methyl-D-aspartate (NMDA) glutamate receptor subtype has been found to influence neuronal development including the amount of dendritic arbor per cell (Kalb, 1994). In the hippocampus, an interaction between androgens and the NMDA receptor has been implicated in neuronal development (Pouliot, 1996). The purpose of this study was to determine if antagonism of NMDA influences dendritic development in the SNB. A non-competitive NMDA antagonist, MK-801 (1.0 mg/kg s.c.), was administered to male rat pups from postnatal day (pd) 7 to pd 28. The bulbocavernosus (BC) and levator ani (LA) muscle weights of MK-801 treated males were comparable to normal males when corrected for the decreased body weight of the MK-801 individuals. Soma size and distribution were analogous to normal control males. The BC/LA weight and soma size suggested that the androgen levels remained unaffected; therefore, any observed changes in dendritic arbor and distribution resulted primarily from NMDA antagonism. NMDA antagonism was found to altered dendritic growth in the SNB. Dendritic arbor per cell was attenuated by 40% when compared to the control. An interaction between NMDA and androgens would be likely to occur during neuronal development in this spinal nucleus.  |CURRENT INFO|

1999 REU Mentor:   Dr. Dale Sengelaub, Department of Psychology & Program in Neural Science

Learning to Time
Past research has shown that pigeons can learn to respond differentially using temporal discriminations. Several theories have been proposed to explain timing behavior in animals. Two dominant theories, Scalar Expectancy Theory (SET; Church, Meck, & Gibbon, 1994; Gibbon, 1977, 1991) and Behavioral Theory of Timing (BeT; Killeen & Fetterman, 1988; Killeen, 1991), have focused on the pigeon's behavior once performance has stabilized. However, these authors do not attempt to explain the learning process that leads to timing. In response to this shortcoming, Armando Machado has proposed another theory, Learning to Time (LeT; Machado, 1997; Machado & Cevik, 1998; Machado & Keen, 1999).
     This theory focuses on the learning process as well as stabilized performance and proposes that the animal uses its own behavior to time events or intervals. In an attempt to further our knowledge of the learning process, we conducted a temporal discrimination experiment. In this experiment, the animal learned to make one response after a short temporal interval and another response following a long temporal interval. This experiment consisted of 3 phases: (1) Acquisition -- In this phase, the animals learned the temporal discrimination; (2) Extinction -- In this phase, the animals were familiarized with a lower rate of reinforcement to prepare them for the next phase; (3) Generalization -- In this phase, varying intervals were used to further study the animal's bisection of the temporal interval, which is the time or point at which their responses to each side are equal. We found that pigeons do learn this discrimination and respond accordingly. We also found several identifiable steps in the learning process for each bird. Quantified results tended to not support the predictions of SET. The results generally supported LeT's predictions.  |CURRENT INFO|

1999 REU Mentor:  Dr. Armando Machado, Department of Psychology

Pavlovian Cues Predicting Food Suppress Corticosterone Following Food Reduction
Prior research has shown that an increase in plasma corticosterone accompanies negative consummatory contrast, but occurs on the second, not the first day of a downshift. Our experiment sought to demonstrate that environmental cues play a role in modulating corticosterone release following reductions in expected reward. All subjects were given a 32% sucrose solution for 33 days and provided with very salient visual, taste and odor cues to act as conditioned stimuli (CS+s). They were then downshifted to a 4% solution. At this time, 3 groups were established. The control group continued receiving the CS+s all 4 days of the downshift. A second group received no cues on Day 1, but received CS+s on the following 3 days. A third group received no cues on Days 1 and 2 and received CS+s on Days 3 and 4. Hormone assays revealed a suppression of corticosterone in the first group relative to the uncued groups on Day 1, a suppression of corticosterone on Day 2 in the second group, and a suppression of corticosterone on Day 3 in the third group. These results suggest that cues predicting the 32% solution can suppress or delay the corticosterone response that accompanies negative contrast effects.  |CURRENT INFO|

1998 REU Mentor:  Norm Pecoraro, Department of Psychology (Timberlake lab)

Growth and Development as an Indirect Genetic Trait in Dendrobates auratus Frogs
Indirect genetic effects occur when genetically based traits in one individual serve as in environmental source of variation in the phenotype of another individual. I studied behavior as an environmental effect on the growth and development of Dendrobates auratus tadpoles. I bred Dendrobates auratus frogs; and the resulting tadpoles were then to be paired with siblings and non-siblings. The hypothesis was that tadpoles from certain families would inhibit the growth of non-siblings through dominant/aggressive behavior. I was unable to obtain enough tadpoles to run the complete experiment because 56 percent of the pairs did not produce clutches, 92 percent of the total egg clutches failed, 44 percent of the tadpoles I was able to raise died. Of the surviving tadpoles, non of the non-siblings fit into my pairing criteria. I observed the behavioral activities of a total of five tadpoles, two as pairs and three as individuals. My preliminary conclusions are that one tadpole of paired siblings is usually more aggressive in initiating contact, and that paired tadpoles are relatively more active than non-paired tadpoles. Currently I am rearing the eggs by hand in an effort to improve egg clutch survival. Thus far this method has increased egg clutch survival by 34 percent.  |CURRENT INFO|

1998 REU Mentor:  Maura Maple, Department of Biology (Brodie lab)

Multi-unit Hippocampal Recording During Eye Blink Conditioning in Rat
In this experiment, we looked at the correlation between hippocampal activity and the learned eye blink response. The data collected from the eight rats used in this experiment, will be used as pilot data for an experiment dealing with the effects of amygdaloid lesions on hippocampal activity and eye blink conditioning. Therefore, this experiment includes sham lesions in the amygdala using a saline solution. We implanted multi-unit recording electrodes in the hippocampus, and measured eye blink behavior with subcutaneous EMG electrodes in the obicularis occuli. To test the learning responsiveness of the hippocampus we used standard eye blink conditioning procedure: a tone was given followed by a shock. The tone was 450 ms 350 ms ISI at 2 kHz, while the shock was a simple delay conditioning and administered during the last 100 ms. The rats received a hundred tone and shock trials, split up into blocks of ten trials. We ran the rats on a average of ten days or until they reached criteria, which was 75%. We were looking for neural and muscular activity between the onset of the tone and the shock. It takes an average of five days for the rat to show good unconditioned responses (US) to the eye blink stimulus. Sham 3 reached criterion in two days while sham 2 took ten days. A good US was after tone onset, the firing of a cell in the hippocampus which happens at the same time as the obicularis occuli registered activity. A bad US would be activity, like eye blinking or exaggerated head movement, before the tone onset and these trials were disregarded. There should be an adequate correlation between the hippocampal activity and eye blink learning, since only minor damage has been done to the hippocampus region.  |CURRENT INFO|

1998 REU Mentor:  Matthew Blankenship, Department of Psychology | Program in Neural Science (Steinmetz lab)

Coordination of Vocal and Visual Display in Brown-Headed Cowbirds
Male brown-headed cowbirds (Molothrus ater) frequently perform an elaborate visual display during song. This display involves raising head and neck feathers, spreading the wings, and concluding with a bow. The stereotyped song of cowbirds contains two to three introductory note clusters and a final high-frequency whistle, all of which are separated by short inspirations. It is unknown whether the muscle groups responsible for the visual display are coordinated with those responsible for song production. In order to address this question, we studied vocal and visual display by filming cowbirds with high-speed video and simultaneously recording air sac pressure, vocalizations, and wing movements. The magnitude of wing spread varies substantially between songs of an individual. However, a partial downstroke of the wings during the display is consistently synchronized with each inspiration, occurring 18 ± 1.0 ms, 17 ± .09 ms, and -0.5 ± 1.2 ms from the peak inspiratory pressure for the first (~36 ms), second (~40 ms), and third inspirations (~34 ms), respectively. This synchronization of the wing's downward movement with the respiratory pattern may facilitate respiratory muscle activity during singing. In any case, the synchronization clearly demonstrates coordination between the motor systems of song production and wing movement, although the neural substrates of this integration are still unknown.  |CURRENT INFO|

1998 REU Mentor:  Dr. Franz Goller, Medical Sciences Program (Suthers lab)

The Role of Dopamine in the Organization of Movement Patterns in Perinatal Rats
Perinatal stimulation (labor contractions, stroking) is necessary for the onset of pulmonary respiration and facilitates the initiation of suckling in neonatal rats (Rattus norvegicus). In addition, compressions simulating labor contractions have been found to elicit a change in perinatal movement patterns. Flexion of the torso is a common fetal movement in utero; extension is rarely observed. However, following 5 compressions (1 compression / minute for 5 minutes), fetal rats emit more torso extensions than flexions. Postnatally, extensions are an important component of the movement patterns observed in suckling onset. In the current experiments, we investigated the mechanism by which labor contractions elicit an increase in torso extensions. Recently, it was found that plasma dopamine is elevated in compressed perinates, indicating a possible role for dopamine in the behavioral changes observed following uterine contractions. Further, haloperidol (a dopamine antagonist) administered prior to compressions prevents the expression of torso extensions. In the first experiment, Gestation Day 21 fetal rats were externalized from the dam's body, and fetuses were injected with L-Dopa, a dopamine agonist. L-Dopa, in the absence of compressions, significantly increased torso extensions, providing further evidence that dopamine mediates the behavioral response following uterine contractions. In an additional experiment, caffeine, a nondopaminergic stimulant, increased fetal activity without changing the ratio of torso flexions to extensions. It appears that adopamine-dependent mechanism organizes these neonatal movement patterns and that the transition from flexions to extensions is not mediated by a change in general arousal or potentiated activity.  |CURRENT INFO|

1998 REU Mentor:  Regina A. Abel, Department of Psychology (Alberts lab)

Glucocorticoids Modulate Memories for New Food Locations Particularly During Periods of Food Stress
Previous research has shown that a) sudden food reductions increase circulating corticosterone, and b) that glucorticoids may be involved in the modulation of memory for emotional events and spatial locations. This experiment tested whether a glucocorticoid receptor (GR) antagonist RU38486 would impair memory for a new food location following periods of food stress. Three groups of intracerebroventricularly (i.c.v.) cannulated rats were run in a successive contrast procedure on an eight arm radial maze. Two groups received 32% sucrose solution in a fixed arm of the maze once daily for 25 days. Another group received a 4% solution in a fixed arm. The 32% groups were downshifted to a 4% solution for two days to promote food stress and an adrenal response. On subsequent days, the 32% groups were upshifted and downshifted on alternate days. They received the 4% always in the original training location, whereas they received the 32% solution henceforth in a new location. One 32% group was given the GR antagonist i.c.v. on days when the 32% solution was available in the new location, whereas the other 32% received saline i.c.v. on those days. The 4% group received a 4% solution in original and new locations on alternate days. The 4% group received the GR antagonist on days when the 4% solution was located in a new location. The 32% given RU38486 made more errors on the day following the first upshift than did the 32% saline group and the 4% group. However, the 32% group given RU38486 did not make more errors in finding the training location than did the control groups, suggesting that the memorial impairments were not general impairments. These results suggest that glucocorticoids are involved in modulating memories for new spatial locations particularly during periods of food stress.  |CURRENT INFO|

1998 REU Mentor:  Norman Pecoraro, Department of Psychology (Timberlake lab)

Posture as a Signal in Aggression of Male Three-Spined Sticklebacks
Although behavior and stimulus function in three-spined sticklebacks have been extensively explored, few studies have dealt with the effects of posture on aggression. Classic studies indicate that headdown posture is an aggression-releasing stimulus in sticklebacks (Tinbergen and van Iersel 1947). However, more current studies in our lab have shown that sticklebacks may direct fewer bites to a headdown model than to a horizontal one. This project re-examined and extended the latter research. The response of male sticklebacks to headdown and horizontal postures was tested by using male dummies as stimuli, and the response of males with prior exposure to horizontal dummies (experienced) was compared to that of males with no prior exposure (inexperienced). Experienced males showed a trend toward biting a headdown dummy more than a horizontal one presented simultaneously. Inexperienced males bit a horizontal dummy more than experienced males did. Further, inexperienced males directed more bites to the horizontal dummy than to the headdown one. The intimidating effect of a headdown opponent may therefore lead inexperienced males to inhibit their attack on that opponent and instead redirect their attack to the less threatening horizontal one. For both groups, the total number of bites (headdown + horizontal) performed during a 56 minute testing period decreased over time. Thus, I obtained evidence for posture-specific response and habituation to posture. These results provide further insight into the adaptive value of posture and the influence of habituation in stickleback communication.  |CURRENT INFO|

1998 REU Mentors:  Dr. William Rowland, Kimberly Bolyard, Department of Biology (Rowland lab)

Bridging the Baby Gap: New Methods in Assessing Infant Responses to Adult Speech
When directed to infants, adult speech is characterized by higher pitch, slower tempo, and exaggerated prosody. The acoustic modification of speech to infants occurs across most languages and cultures. Many studies have revealed that infants attend to and prefer the infant-directed (ID) speech style. However, previous studies have limited infants' behavioral responses by presenting speech stimuli in the context of an impoverished environment. Using speech sounds presented in a complex environment, the current study examined the effects of ID speech on multiple measures of infant behavior. Ten infants, 8 months old, participated in the study. The infants were placed in a high chair and presented with three toys. A speaker next to the infant played the stimuli, consisting of 16 alternating intervals of ID speech, adult-directed (AD) speech, and silences. Each stimulus interval was 15 seconds in duration. The dependent variables measured were the frequency and duration of: head turns to the speaker, looks to toys, and contact with toys. We hypothesized that infants would shift their attention between stimuli less during ID speech. Using a Friedman 2-Way ANOVA by Ranks for each measure, we found an effect of trial on the behavior of the infants. A Wilcoxon Signed Ranks Test revealed that the infant behavior varied reliably with the presence or absence of speech. During speech, infants exhibited more head turns toward the speaker, less looking at toys, and less contact with toys. However, behavior did not vary with the specific type of speech presented. We concluded that testint infants' responses in a complex environment revealed an overall reduction in behavioral activity in response to speech.  |CURRENT INFO|

1998 REU Mentor:  Michael Goldstein, Department of Psychology (West lab)

Huddling by Rat Pups: Groups vs. Individuals on a Shallow Thermocline
Different animals employ different behavioral and physiological mechanisms to regulate their body temperature. Norway rats (Rattus norvegicus) have internal and external methods of thermoregulation, including shivering and group huddling. Infant rats, however, are very limited in their capacity to thermoregulate independently. They do not shiver and must rely upon huddling in groups to conserve energy and maintain body temperature. Huddling is an important aspect of rat behavior from infancy through adulthood, serving critical physiological and social functions in infancy, and gaining importance as a social behavior in adulthood. This study compared the ability of individual 7-day-old rat pups and groups of eight littermates to thermoregulate on a shallow thermocline (28-47° C). Our results so far suggest that groups pups are better able to thermoregulate on a shallow thermocline than are individual pups. Groups tended to aggregate and aggregates tended to move to an average temperature of 34.7° C by the end of a 15-minute observation period. Individuals, by contrast, explored thermocline space more randomly than individuals in a group. This suggests that the thermo-detection capabilities of the huddle are more advanced than those of individuals because group thermoregulation is an emergent property of the interactions of individuals within the huddle. This study sets parameters within which to further investigate the self-organization of group thermoregulatory behavior.  |CURRENT INFO|

1998 REU Mentor:  Dr. Jeff Schank, Department of Psychology (Alberts lab)

The Costs and Benefits of Elevated Testosterone on Activity, Locomotor Performance, and Coloration in Sceloporus jarrovi
Marler and Moore (1988) showed that male mountain spiny lizards, Sceloporus jarrovi, with higher levels of testosterone, have a lower survivorship than males with normal levels. Lower survivorship could be caused by an "increase in conspicuousness or a reduced energy balance" (Marler and Moore 1988). The hypotheses tested here try to explain the costs and benefits of having elevated testosterone. We replicated the experiment by Marler and Moore (1989) which found an increase in activity in testosterone treated males. We also tested the hypothesis that an increase in activity would be caused by a higher preferred body temperature in T-implanted males, requiring an increase in basking time. We also tested the idea that T-implanted males have increased sprint speed and stamina. The last hypothesis tested was that the neck and chests of T-implanted males have a deeper blue coloration than do the controls. Marler and Moore's results were replicated in that T-implanted males were shown to be more active in all three (morning, noon and evening) scans. When seven lizards were analyzed for activity by looking at their pre-implanted and post-implanted activity, Marler and Moore's results were again replicated. We also found that a higher preferred body temperature was not a reason for this increase in activity because there was no difference between the body temperatures of controls and T-implanted males. In the sprint speed comparisons, T-implanted males were faster in all 0.25 and 0.5 meter distances. There was also a trend that suggests that testosterone affects stamina. It was implicit in the results that testosterone affects color, because of the ten lizards with the deepest blue, eight had T-implants. Testosterone could be costly to a lizard because it increases activity, locomotor performance, and coloration, increasing energy usage and/or conspicuousness. Increased activity and performance could help lizards escape predators, patrol their territory, or search for food more easily. Deeper blue might attract females but this coloration could also attract predators or rival males.  |CURRENT INFO|

1997 REU Mentor:  Matthew Klukowski, Department of Biology (Craig Nelson lab)

Suppression of Adrenal Responses to Downshifts in Food Quality by Inducing Postive Expectancies Using CSS Presented in Various Sensory Modalities
This experiment investigated the hypothesis that the lack of a rise in plasma corticosterone on the first day of a downshift in incentive shift studies is due to the fact that a positive expectancy of food can suppress this adrenal response. Using a successive negative contrast procedure, 50 rats were given 5 min access to a 32% sucrose solution once daily on a plus maze for 16 days, and were then downshifted to a 4% solution. During training, three of the groups were exposed to explicit cues in different sensory modalities while drinking the 32% solution. These cues included visual, flavor, or odor cues. The two control groups were exposed to ambient room cues only. All groups were shifted to a 4% sucrose solution on Days 17 and 18. A between groups comparison of plasma corticosterone in the control groups sought to establish the typical rise in the hormone on the second day post-shift. The explicitly cued groups were downshifted on the first day post-shift in the absence of their positive cues, which were returned on the second day post-shift. The groups positively cued on the second day were expected to have lower plasma corticosterone that day than the uncued control group. Intake and behavioral profiles showed the typical suppression of intake and increased search behavior during the downshift. Hormone assays are pending.  |CURRENT INFO|

1997 REU Mentor:  Norman Pecoraro, Department of Psychology (Timberlake lab)

Determining the Specific Effect of Amnoitic Odor on Movement Patterns in Norway Rats (Rattus norvegicus)
This experiment is part of an ongoing series of studies investigating the onset of suckling in newborn Norway rats (Rattus norvegicus). In the current study, we examined whether newborn pups surrounded by the odor present at birth would exhibit more distinct, organized behavior patterns compared to control pups not surrounded by the familiar odor stimulus. Gestational day 21 (day of birth 21.5) pregnant dams were individually housed in a birthing cage. Shredded filter paper was used as bedding to absorb amniotic fluid and birth odor (a necessary stimulus for suckling onset in newborn rats). Two newborn pups were removed from the nest soon after birth and exposed to a time and temperature regime simulating the typical postpartum environment. Subjects were then assigned to one of two conditions: birth odor or no odor (control). Following a two-minute baseline period, pups in the birth odor condition were surrounded by filter paper from their natal nest; pups in the no odor condition were surrounded by clean filter paper. While there was no difference in overall activity between the groups, preliminary results indicate that birth odor elicits alterations in the pattern of behavior, suggesting that olfaction plays an important role in postnatal behavioral organization in newborn rat pups.  |CURRENT INFO|

1997 REU Mentor:  Regina A. Abel, Department of Psychology (Alberts lab)

Sex and Violence in Stickleback: A Study of Motivational Conflict
The threespine stickleback, Gasterosteus aculeatus, is a fish species in which the breeding male establishes a territory and builds a nest. Males are thus faced with a conflict situation so that, in order to reproduce, they must attack intruding males but respond sexually to intruding females. We used a dummy-presentation procedure to study how territorial males respond when presented with a male and female simultaneously. We also determined how distance from nest and habituation affected this process. The dummies consisted of two epoxy castings: one simulated a threatening male and the other a courting female. Zigzagging and biting events were used to measure the amount of sexual and aggressive activity, respectively, that males directed to the conspecifics. In both experiments the subjects responded most to the male dummy, primarily with aggressive behavior, but there was a negative correlation between distance from nest and aggression to both stimuli. Also, aggression towards the dummies decreased over time. Courting was overwhelmingly directed to the female dummy, especially far from the nest. Despite the wide degree of individual variation, male stickleback were thus able to differentiate between sexual and aggressive stimuli and responded to each in a functionally appropriate manner.  |CURRENT INFO|

1997 REU Mentor:  Dr. William Rowland, Department of Biology (Rowland lab)

A Dewlap of a Different Color: Analysis of Throat Fan Pigments in Anolis Lizards of the 'Grahami Series'
Lizards of the genus Anolis possess a specialized and colorful display organ - a 'dewlap' - that is revealed only during signalling. Factors such as habitat lighting, spectral sensitivities of anoles and of their predators, and presumably the need for reliable species identification badges, have contributed to the broad diversity of dewlap color patterns seen among the nearly 300 species in the genus. In a study at the University of Puerto Rico in the early 1960's, paper chromatography revealed that pteridines were the main sources of dewlap color in Puerto Rican anoles, aside from yellow carotenoids. In the present study we used thin-layer chromatography and spectral analysis to identify the pigments underlying dewlap and body coloration in the 'grahami series' anoles. This evolutionary radiation comprises seven closely-related species: six which evolved from a common ancestor on Jamaica, and one species derived from Jamaican stock that evolved on Grand Cayman. We also sought to determine whether the distribution of pteridines among grahami series members were consistent with proposed phylogenetic relationships for these lizards. Results showed that Puerto Rican and grahami series anoles share the same types of pteridines, although the proportions of each type varied within and between the two Anolis groups. The presence of pteridines with spectral peaks in the 'visible' range (400-700nm) was variable among species, but pteridines whose spectral peaks fell in the near ultraviolet (315-400nm) were present in the the body skin of all taxa in both evolutionary radiations. All Anolis species examined to date possess UV-sensitive photoreceptors, and we speculate that body skin pteridines with UV spectral peaks might increase congener visibility. With one exception, the distribution of pteridines types among grahami series members was consistent with current phylogenetic hypotheses for this group. Finally, we found that Anolis grahami and Anolis conspersus, a putative ancestor-descent species pair, possess the same dewlap pteridines despite the fact that the former's dewlap is orange/yellow and the latter's is blue and UV-reflective. Spectral analysis of dewlap extracts showed that although the A. conspersus dewlap contains the same types of pteridines as that of A. grahami, only trace amounts are present in A. conspersus. Moreover, the A. conspersus dewlap lacks carotene, whereas this compound is abundant in the A. grahami dewlap. These differences in pigments, however, still may not fully explain why A. conspersus has evolved dewlap coloration that is so radically different from other grahami series members. Histological study of dewlap tissue may expose structural innovations underlying the ability of the A. conspersus dewlap to reflect blue and UV light so effectively, and research on habitat lighting and the spectral sensitivities of A. conspersus predators may provide a more complete picture of this species' unusual solution in signalling with color.  |CURRENT INFO|

1997 REU Mentor:  Dr. Joseph Macedonia, Department of Biology & CISAB

An Experimental Investigation of Whether Female Brown-Headed Cowbirds Avoid Nests Previously Parasitized by Conspecifics
Often nests are parasitized more than once by the avian brood parasite, the brown-headed cowbird. Evidence from field studies suggest that female cowbirds do not avoid laying in previously parasitized nests. Using captive birds, we experimentally determined if female cowbirds prefer nests that were not parasitized by other females. Individual female cowbirds were introduced to a chamber with two arms each containing a nest attached to opposite corners. In order to simulate nesting activity, visual and aural stimuli of the same host species was presented from both arms. A conspecific cowbird egg was placed in one of the nests. To determine whether females avoided the parasitized nest, the rate of visitation to the nests and laying activity was ascertained. There was no statistical difference (n = 13, P = 0.44) between the rate of visitations to the nest with (mean = 0.38 per hr.) and without (mean = 0.84 per hr.) the cowbird egg. Three of the 13 females tested laid eggs in one of the nests. Two of the eggs laid were found in the nest with the artificially introduced cowbird egg. Based on the rate of nest visitation, individual female cowbirds showed no preference when simultaneously presented a parasitized and non-parasitized nest. Female cowbirds may not have the ability to recognize conspecific eggs. Alternatively, because female cowbirds often encounter a limited number of nests, they may be restricted in their choice of nests.  |CURRENT INFO|

1997 REU Mentor:  Dr. Tom Ford, Department of Biology

The Effects of Larval Developmental History on Performance in the Terrestrial Environment
For organisms with biphasic life cycles, metamorphosis is arguably the most important life history event because age and size at which metamorphosis occurs dramatically influences fitness. While a tremendous amount of theoretical and empirical work has addressed the effects of varying age and size at metamorphosis, few studies consider the effect of metamorph condition on fitness. We propose to relate critical components of metamorph morphology to performance in an effort to develop a more complete view of how larval life history affects adult fitness. The spadefoot toads Scaphiopus multiplicatus and S. bombifrons have evolved two different, inducible larval morphs, omnivores and carnivores. The adaptive switch from omnivore to carnivore allows tadpoles to escape desiccation in rapidly drying ponds where omnivorous morphs would most likely die before initiation of metamorphosis. Carnivores are selected against in long-lived pools because they have lower fat reserves at metamorphosis and hence are more susceptible to starvation than omnivores. We hope to determine if there are any other costs (e.g., performance costs) in the terrestrial environment associated with the switch from the omnivorous to the carnivorous morph. We plan to quantify the statistical relationship of jumping ability and endurance with larval developmental history (omnivore/carnivore) and metamorph morphology. Several aspects of morphology important in locomotion will be measured in the lab (e.g. mass, fat body content, muscle thickness, SVL, etc.). Path analysis will be used to identify the direction and magnitude of direct and indirect relationships among morphological elements and performance measures. Statistical similarity of the path models for omnivores and carnivores will indicate that the relationships between larval morphology and performance are the same for both morphs while statistical differences between models will indicate morph-specific effects on performance.  |CURRENT INFO|

1997 REU Mentor:  Tony Frankino, Department of Biology (Sinervo lab)

Responses of Testosterone-Treated and Control Chicks to Novel and Starling Stimuli
In a variety of vertebrates, the hormone testosterone has been suggested to have a direct effect on males' ability to focus their attention on familiar tasks (Andrew 1972a). In an earlier study, Jones and Andrew (1992) found that when the appearance of the familiar food is altered, or when a novel object is present in the food dish, feeding by adult chickens will not occur as long as the attention of birds is directed at the novel stimulus. They found that adult chickens with normal testosterone levels focus more attention on the novel object, while adults with low levels turn their attention away from the novel stimulus more readily and shift there attention to the food. I replicated the approach used by Jones and Andrew (1992) with young (i.e., less than 2 weeks old) chicks to investigate whether testosterone's effect on feeding behavior was dependent on the birds' stage of development. The chicks were trained on 9 of the 11 days to eat familiar food, and on the remaining 2 days were tested with an unfamiliar (i.e., novel) stimulus. My approach consisted of observing the effects of introducing novel objects or altering the color of food on the chicks feeding behavior. The novel objects that I used differed from those used in the earlier study of adults, and in contrast with the earlier study did not have an effect on the chicks' behavior. Moreover, their was no difference in the behavior of testosterone-treated and control chicks. However, a change in food color similar to that used by Jones and Andrew produced a dramatic decrease in time spent feeding and the amount of food eaten. As in adults, testosterone treatment appeared to alter the responses of chicks to the change in food color. Interestingly, however, the effect of testosterone in young male birds was the reverse of what was observed in adults, i.e., controls rather than testosterone-treated chicks showed the greatest response to the novel stimulus. These findings suggest that the effects of steroid hormones may change during development, resulting in dramatically different patterns of behavior at different developmental stages.  |CURRENT INFO|

1997 REU Mentor:  Martha H. Bowman, Department of Biology (Phillips lab)

The Ecology of Parent-Infant Communication: Behavioral Consequences of Infant-Directed Speech
When addressing pre-linguistic infants, adults tend to use a distinctive speech register characterized by high pitch, prolonged vowel sounds, and long pauses. This infant-directed speech has been shown to increase infant arousal. However, previous studies were done in laboratory environments that minimized the infants' exposure to other natural stimuli. The current study investigated the effects of infant-directed speech on social and exploratory behaviors of infants in a naturalistic environment. Twelve infants, ranging in age from 8-12 months and varying in locomotor ability from crawling to walking, were examined. Infants were free to explore a playroom and adjacent hallway during a ten-minute playback of prerecorded speech. Stimuli consisted of alternating thirty-second intervals of infant-directed speech, silence, and adult-directed speech. Six dependent variables were measured: frequency, duration, and direction of head turn and locomotion. We hypothesized that infant-directed speech would increase the frequency and duration of head turns in the direction of the sound source and decrease the frequency and duration of locomotion.  |CURRENT INFO|

1997 REU Mentor:  Michael Goldstein, Department of Psychology (West lab)

Differenece in Thermotactic Abilities of Group Compared to Individual Rat Pups (Rattus norvegicus) on a Shallow Thermocline
Mammals need to regulate their body temperature to survive. Temperature usually varies slightly across mammalian species. For instance, Norway rats (Rattus norvegicus) regulate their temperature around 37 degrees Celsius. Rat neonates however, are physiologically extremely limited in their ability to thermoregulate independently, and have been called poikilotherms. Jeff Alberts showed that rat pups can regulate their temperature by huddling together. They do so by climbing on and around each other decreasing their surface area and reducing heat loss when cold and when hot they can reduce their temperature by exposing more of their surface area. Alberts discovered that when the ambient temperature is cool pups in the nest orient and flow downward into the huddle, whereas when the ambient temperature is hot pups orient and flow upward. Thermotaxis is orientation and movement towards heat and is the behavioral basis for newborn rat pups' ability to thermoregulate in a huddle. According to Ogilvie & Stinson,the most important factor for a newborn or young animal is not contact with others, but temperature. This study assessed the validity of this conclusion: whether there are differences in the thermotactic abilities of pups in groups vs. isolation. We developed a thermocline consisting of a rectangular dome of Plexiglas with a Styrofoam arena placed on a copper bar. This thermocline is unique because previous thermogradients used to study neonatal mammals had steep thermogradients (e.g., ranging from 18°C to 45°C), whereas our thermocline has shallow thermogradients. Another unique aspect is that our thermocline has two "peaks" (one on each end) and a "valley" in the middle. In this study the thermocline was intended to detect fine differences in the ability of rat pups to behaviorally thermoregulate. We videotaped four groups of eight and sixteen individual 7-day old rat pups for one hour on the thermocline. Their position was precisely determined every 10 seconds using a modified version of NIH Image. Our results showed that groups find warmer temperature more quickly than individuals do. Individuals tend to stay in the middle for the first 30 minutes then only some slowly move to warmer temperatures; whereas groups move up the thermocline rapidly and then gradually level off. The probability that groups and individuals are the same is extremely unlikely (at 14 minutes p=0.02, 30 minutes p=0.000005, and 60 minutes p <0.007). These result show that individual pups in a group exhibit more rapid and greater thermotaxis than individuals by themselves. This result supports the view that interactions among pups within a huddle serve important biological functions such as thermoregulation and energy conservation.  |CURRENT INFO|

1997 REU Mentor:  Dr. Jeffery C. Schank, Department of Psychology & CISAB (West lab)

Effects of Different Wavelengths of Light on Magnetic Compass Orientation by the Beetle Tenibrio molitor
Previous work by (Arendse 1978) has shown that the flour beetle Tenebrio molitor is capable of orienting relative to an earth-strength magnetic field. The experiments here were carried out to determine which of two recognized magnetoreception mechanisms are utilized by this species. Arendse (1978) provided evidence that T. molitor sense magnetic field polarity. These findings are consistent with a magnetoreception mechanism based on particles of magnetite. Arendse's conclusion that T. molitor senses magnetic field polarity, however, was based on evidence that beetles could distinguish between the two ends of a horizontal magnetic field. If correct, this would rule out a second type of magnetoreception mechanism, i.e., one involving a specialized photoreceptor. A photoreceptor-based magnetoreception mechanism is expected to be insensitive to magnetic field polarity, requiring the animal to use the slope of the magnetic field to distinguish between the two ends of the magnetic axis. The use of the slope of the magnetic axis, rather than polarity, can not be ruled out in Arendse's experiments, however, because the magnetic field had a weak vertical component producing an inclination of as much as 4 degrees. Therefore, these results do not rule out the possibility that T. molitor has a photoreceptor-based magnetoreception mechanism instead of (or in addition to) the type of mechanism suggested by Arendse. To investigate the possibility of a photoreceptor-based magnetoreception mechanism in T. molitor, we observed the magnetic compass orientation of these beetles under different wavelengths of light. This approach has provided evidence for the use of a light-dependent magnetoreception mechanism in the eastern red-spotted newt Notophthalmus viridescens and in Drosophila melanogater. The magnetic compass orientation of T. molitor was tested under full spectrum light and wavelengths of light greater than 500 nm which produced a 90 degree shift in the responses of N. viridescens and D. melanogaster. However, the magnetic orientation of T. molitor was not significantly different under full spectrum and long-wavelength light. These findings support Arendse's original conclusion that T. molitor non-light-dependent. It would appear, therefore, that there are at least two distinct types of magnetoreception mechanisms in terrestrial organisms.  |CURRENT INFO|

1996 REU Mentor:  Dr. John Phillips, Department of Biology (Phillips lab)

Higher Order Conditioning in Rats: A Behavior Systems Approach
This experiment is a part of an on-going research study which is attempting to combine the classical laboratory approach with the study of behavior with that of the ethological-ecological analysis of behavior. And, in doing this, we have applied some of the principles and paradigms of the laboratory but always with reference to and in the context of the behavior systems of the species. We have set out in this experiment to demonstrate tat a CS presented temporally far from the UCS can produce conditioning and, in fact, better conditioning than a CS that is paired simultaneously with the USC. To illustrate this phenomenon, we have used the CS of a rolling ball-bearing and the test of higher-order conditioning. With the test of higher-order conditioning, we are able to employ a second stimulus - the rolling ball-bearing - which can act as a probe to indicate that a different part of the subject's behavioral system is being stimulated than has been in traditional experiments. And, we would argue that this stimulation is due to the consideration of the behavior system of the species. Also, if our method of conditioning succeeds, we contest that this supports not only a behavior systems approach but also our own model of rat feeding behavior. We were not completely successful in our pursuits, but our data still did show that conditioning with the ball-bearing and the longer stimulus was more effective. These results add some validity to our hypothesis and approach, but further research would be necessary before any conclusive statements could be made.  |CURRENT INFO|

1996 REU Mentors:  Dr. William Timberlake & Kathleen Silva, Department of Psychology (Timberlake lab)

Reinforcement of Novel Behavior in Pigeons
Karen Pryor's paper (1969) "The Creative Porpoise: Training for Novel Behavior", mentions the possibility of generating novel behavior in pigeons by reinforcing a series of different, normally occurring behaviors. To determine whether this could actually be accomplished we designed a pilot study to increase the frequency of novel behaviors in three pigeons under controlled experimental conditions. Our study consisted of four phases: (1) recording the range of behaviors displayed under a free-food baseline; (2) conditioning for novel behavior; (3) extinction; and (4) a return to conditioning. One problem we encountered was that even though research suggests that the frequency of novel behaviors may be increased by contingent reinforcement, the effects of reinforcement on response extinction on response variation. We suggest that if novel behaviors (occur/arise) predominately in the context of reinforcement rather than extinction, then the novel response can be considered an operant. Our findings suggest that behaviors are constructed by successive approximation and not really novel and that there is not evidence for variability as an operant thus leading to reinforcement. In our study reinforcement of normally occurring behaviors led to novel behavior. Shaping of exaggerated behaviors resulted in the occurrence of new behaviors that could not be predicted on the basis of any initial behavior.  |CURRENT INFO|

1996 REU Mentor:  Dr. Armando Machado, Department of Psychology (Machado lab)

Investigation of a Correlation Between Yolk T Levels and Growth Rate in Red-Winged Blackbirds
The young of red-winged blackbirds, Agelaius phoeniceus, hatch asynchronously over a two-day period with early-laid eggs hatching first. Mothers begin to feed their young upon hatching and therefore, early hatchlings begin to grow before their later-laid siblings hatch. Because larger hatchlings are able to better compete for and obtain resources from their parents, the early hatchlings have a significant advantage over their younger siblings. Among the many adaptive hypotheses for asynchronous hatching is Lack's (1954) proposal that it allows for increased parental fitness through an optimal clutch size. Under unfavorable conditions, asynchronous hatching may provide a means for reducing the clutch to an optimal size by the loss of the youngest or smallest hatchling: under favorable conditions, the survival of the entire clutch is possible. A nonadaptive explanation for asynchronous hatching would involve an alternative strategy to counter the possible costs of such a hatching pattern (i.e. loss of youngest young). Using radioimmunoassay techniques, Joe Lipar (1995 unpublished) determined that the testosterone (T) concentration in the yolks of red-winged blackbird eggs increases with laying order from the first-laid egg to the last. Schwabl (1993) observed a similar pattern in the egg yolks of canaries, Serina canaria. Schwabl also observed an aggression hierarchy among sibling hatchlings that corresponded directly with yolk T levels, regardless of hatchling gender. The correlation between yolk T concentration and hatchling aggression may prove to be a mechanism to counterbalance the disadvantage of late-laid eggs. In addition, the high yolk T concentrations may have an anabolic effect on embryonic growth and development; such an organizational effect of T could result in increased growth rates for hatchlings with high yolk T levels. To investigate the possible correlation between hatchling growth rates and yolk T, the first and second eggs of each clutch in a wild population of red-wings was injected either with T in sesame oil or with the oil alone (control). Yolk samples were taken on the fourth day of laying, which was the last day of laying in most clutches. Hatchlings were weighed and measurements of the right tarsus were recorded on the first, second, third, fifth and seventh days of hatching to determine growth rate. Also on the seventh day, blood was taken from the hatchlings for an additional investigation of a possible correlation between yolk and blood steroid levels. A significant correlation between yolk T and hatchling growth rate was not found in this investigation; however, it would be premature to dismiss the possibility that testosterone in the egg yolk has a direct anabolic or organizational effect on the growth rate of red-winged blackbirds. One finding shows that the outer, middle and inner layers of the yolk have varying levels of T. In future investigations, adjustments must be made in the techniques for injecting the eggs with steroid or lipid and for withdrawing yolk samples in order to account for the layer variation. Based on recent research, it is highly probable that the concentration of testosterone in the yolk has an effect on the growth rate and consequent survival of red-winged blackbird hatchlings.  |CURRENT INFO|

1996 REU Mentor:  Joseph Lipar, Department of Biology (Ketterson lab)

Huddling in Rat Pups
Huddling is a group regulatory behavior in infant rats (pups). Rat pups huddle in order to thermoregulate and conserve energy (Alberts, 1978). Huddling is the major behavioral activity of infant rats, and it also occurs in adult rats. Huddling is contact behavior requiring sensorimotor coordination. Sensorimotor coordination is the ability to respond to things. Jeff Schank (my mentor) has shown using computer simulation that infant rats huddle by following simple sensorimotor rules. Pups detect other pups by their sense of touch. Since pups cannot see, they use the tip of their nose to find things they like in the arena. All huddling sessions used five- to eight-day old pups, four males and four females. Each pup was numbered 1 through 8 and labeled male or female. The pups were then placed into the huddling arena, which was 12 x 8 x 2 inches. The aluminum arena was temperature controlled by sealing it on top of a 3 gallon water reservoir, which was maintained at a constant temperature by a temperature controlled circulator. The arena and reservoir were then embedded in a large arena in which a fan circulated air throughout the chamber, maintaining a constant temperature. At the start of a session, the pups were uniformly distributed across the arena floor in a rack. In the huddling apparatus, the pups change positions by crawling around one another. The pups were video-taped for twenty-one minutes in the huddling apparatus. Each litter was tested the same way. We tested twelve litters in all with out the mother rat. The data collected was based on the patterns the pups formed. One type of data collected was gender contact. These data consisted of the percentage of male-male, male-female, female-female, and female-male nose to body contacts. If two or more pups were in contact with each other, the data collected were the contact patterns. Another type of data that was collected was called pup nose-to-wall contact. This contact behavior depended on how many pups had their nose against the walls of the huddling apparatus and if they were male or female. The data was recorded using macros developed by Jeff Schank for NIH Image.  |CURRENT INFO|

1996 REU Mentor:  Dr. Jeff Schank, Department of Psychology & CISAB (Alberts lab)

Female Mate Preference and Male Aggression in the Swordtail
Males of the swordtail fish (Xiphophorous helleri) possess a sword-like extension on the ventral part of their tail fin. Laboratory observations reveal that female swordtails prefer males possessing longer swords over those with shorter swords or no sword (Basolo 1990). Because only male swordtails possess a gonopodium (a modified anal fin that serves as an intromittent organ), it appears possible that female preference for swords may have arisen as a byproduct of a mechanism by which females discriminate males from females. That is, the sword may have evolved in part because females were predisposed to prefer individuals with a gonopodium. Thus, I undertook the present study initially to determine if a female's preference for sworded males may have evolved from a preference for male gonopodial size. Store-bought females (whose history is unknown) did not, however, respond sexually in an initial laboratory test in which I presented two yoked dummy males, one with and one without a sword, on opposite sides of the test tank. I also tested males by presenting them with the same two dummies suspended in the center of the test tank and moved on a carousel apparatus. I conducted this test to determine whether males would show more aggressive behavior toward a sworded male than toward an unsworded one. Results suggested that males do use the presence of the sword to determine gender, more readily approaching swordless than sworded dummies. Thus, males may be more attracted to approach and mate with females but reluctant, perhaps intimidated, to approach males. Further tests need to be done to confirm this possibility.  |CURRENT INFO|

1996 REU Mentor:  Dr. William Rowland, Department of Biology (Rowland lab)

The Effects of the Introduction of Relevant and Irrelvant Stimuli on Runway Performance of Testosterone-Treated Chicks
Klein and Andrew (1986) found evidence that testosterone decreases time for a domestic chick to respond to a food dish, increases distractibility when there is a change in the food dish, and decreases distractibility to stimuli not directly involved with obtaining the food reward. Klein and Andrew (1986) suggest that these changes are not due to motivational effects, but rather to an "increase in the ability to specify stably a particular stimulus or type of stimulus as that which is being sought or on which attention is to be sustained." In my experiment, I used a runway protocol very similar to that of Klein and Andrew. I found that testosterone-treated chicks displayed continuous distraction to irrelevant stimuli (changes in the runway walls), whereas control chicks displayed a delayed distraction response to the irrelevant stimuli. I also found that while controls were initially distracted by a relevant stimulus (changes in the food dish) they soon become accustomed to the stimulus. Testosterone-treated chicks, on the other hand, were initially distracted by the relevant stimuli, but never became fully accustomed to the relevant stimuli (as displayed by a continuous, hesitant response while approaching the relevant stimuli). Klein and Andrew's conclusions were not fully supported by data collected in my experiment. In this experiment, I found variations in data collected in my experiment. In this experiment, I found variations in data that supported and conflicted with the conclusions of Klein and Andrew.  |CURRENT INFO|

1996 REU Mentor:  Dr. John Phillips, Department of Biology (Phillips lab)

Developmental Influences on Behavioral Plasticity
Age and size at maturity are two critical components of an organisms life history. Amphibians have been used as model organisms in numerous theoretical and empirical studies examining timing of maturation because larvae can alter development rate in response to environmental variation. However, few studies consider the developmental underpinnings governing adaptive alterations of development rate. Such developmental mechanisms may limit the ability of larvae to development rate. Such developmental mechanisms may limit the ability of larvae to respond to environmental fluctuations. We propose to explore such influences of developmental mechanism on optimization of age and size at metamorphosis in larvae of the spadefoot toad Scaphiopus multiplicatus. When fed a diet of high in fairy shrimp, larvae of these toads alter their behavior and morphology from a typical omnivore to become carnivorous. Shrimp are high in iodine, a constituent of thyroid hormone, which is the primary determine of development rate in amphibians. Consequently, diets high in shrimp allow greater production of thyroid hormones and result in accelerated development. Switching to the carnivorous behavior and morphology is adaptive because high shrimp density is negatively correlated with pond longevity. Hence, tadpoles should assume the carnivorous behavior and morphology when fed shrimp. However, we predict that tadpoles fed shrimp early in ontogeny should have a greater propensity to become carnivorous than those fed shrimp late in ontogeny because tissue sensitivity to thyroid hormone decreases as ontogeny progresses. No difference between tadpoles fed shrimp early versus late in ontogeny will indicate a lack of developmental constraint on the adaptive response. Differences through ontogeny in propensity to assume the alternative behavior and morphology will suggest that mechanisms regulating development affect optimization of age and size at metamorphosis in amphibians.  |CURRENT INFO|

1996 REU Mentor:  Tony Frankino, Department of Biology (Sinervo lab)

Heart Rate Conditioning of Alcohol-Preferring vs. Nonpreferring Rats
Alcohol-preferring (P) and alcohol-nonpreferring (NP) lines of rats have been produced through selective breeding; P rats will consume greater than 5g ethanol/kg body weight per day when given free choice of water, food, and 10% (v/v) ethanol solution, while the NP rats will consume less than 1g ethanol/kg per day. These rats provide a useful animal model for the (HR) conditioned responses (CRs) will be examined in unrestrained alcohol naive rats of both the P and NP lines. A comparison of the HR responses to the conditioned stimulus tone (CS) and the unconditioned stimulus unconditioned shock (UCS) of the P and NP rats will be made. The selective breeding of rats to differing preferences of ethanol has produced behavioral differences between P and NP lines of rats that may result in a difference in responses to fear and the acquisition of HR conditioned responses. It is believed that both the P and NP rats will demonstrate a similar unconditioned response tachycardia (UCR) to the UCS of both the tone and the foot shock. However, it is expected that P rats will have poor conditioning to the tone signal for punishment in comparison to the NP rats, which would suggest that there is a relationship between the risk of alcoholism and the level of conditioning to signals for punishment.  |CURRENT INFO|

1996 REU Mentor:  Dr. Joseph Steinmetz, Department of Psychology | Program in Neural Science (Steinmetz lab)

Project 1: Comparing Song Development in the Dark-eyed Junco
Most of my work done centers on song development in the dark-eyed junco (Junco hyemalis), which is a small passerine. The majority of my work centered on generating visual representations of songs recorded in 1995 and comparing these with songs recorded in 1994. The results show that 8 out of 10 song types produced by 6 males were retained from 1994 to 1995. However, most (6 out of 8) song types were modified substantially over this period. The changes may mean the bird has attached a new note to each syllable thus, making the song sound different. One reason to study song development relates to understanding neural mechanisms. In the past, birds have been used in place of humans for experimentation on neural growth and development. For example, when a person has a stroke, they need to relearn speech and other skills. On a regular basis, birds lose some of their song during the non-breeding season, but lose some of their song during the non-breeding season, but they regain the lost song in the following breeding season. These experiments possess potential medical uses through their application to neural medicine.

Project 2: Search Tactics and Spatial Memory of Female Crickets
The major focus of our research is on mate choice and search behavior of female field crickets (Gryllus integer). Several strategies of search behavior include re-sampling by females; females can presumably return to mate with a previously sampled individual after an indefinite series of encounters with males. Thus, such models of search behavior require that females use a cognitive map. We are using a radial maze to determine whether or not female field crickets can remember the location of calling males after termination of acoustic signals. Our goal is to determine whether females can build a spatial map of the relative position of each male within the radial maze. The extent to which females can recall the relative position of encountered males will limit the degree to which a search strategy incorporate re-sampling.  |CURRENT INFO|

1995 REU Mentors:  Russell Titus, Department of Biolgoy (Ketterson lab) & Dr. Daniel Wiegmann, CISAB

Project 1: Sensory Control of Cricket Predation in the Dessert Kangaroo Rat (Dipodomys deserti)
Cynthia Langley and I are determining which senses a kangaroo rat relies on to hunt insects. Our testing subjects are six adult male desert kangaroo rats. They are being tested in four different experimental conditions: control (having all senses available), hearing deprived, vision deprived, and olfaction (smell) deprived. The rats are run for four days in each condition. Each day includes three trials. For each trial a rat is placed in a 4' x 4' Plexiglas arena filled to a depth of 3" with sand. The rat is allowed five minutes to capture and kill the cricket on each trial. We observe the time it takes for the rat to initially contact the cricket, how many times the rat passes within 2 cm of the cricket without contacting it (a detection error), how many times the rat contacts the cricket and then moves away from the cricket by more than one body length (a tracking error), the total number of contacts before the rat captures the cricket, and the total time it take the rat to subdue the cricket. In the hearing deprived condition, we play a loud white noise during the trials, which drowns out the sounds made by the cricket. In the vision deprived condition, we deprive the rats of any source of visible light. We observe the rats using an infrared viewing device. In the olfaction deprived condition, we place a 5% zinc sulfate solution into their noses which temporarily disables their sense of smell. If a sense is important in predation then we expect to find a significant increase in the time it takes the rat to subdue the cricket and in the number of errors when the rat is deprived of that sense. WE predict that the kangaroo rats rely most on vision. Thus far our results indicate that depriving the rats of hearing has no effect on predation, and depriving the rats of vision causes a significant increase in the time of initial contact, total time to subdue, and detection errors.

Project 2: The Effect of Pheromones on Weaning and Puberty in Female Norway Rats (Rattus norvegicus)
Jeff Schank and I have been trying to determine if the weaning process affects the onset of puberty and how exposure to male rat urine (a putative carrier of pheromones) affects that relationship. Our data includes four consecutive studies. I participated in the fourth study, which observed six families of rats. Each family consisted of a mother and eight pups, four male and four female. Each family was placed in a four compartmented cage having a mother's private compartment, a mother's feeding compartment, a pups' feeding compartment, and a compartment where the mother and pups can interact. In this study, three families were exposed to male rat urine and three families were exposed to distilled water as a control. The families were exposed by placing gauze-filled boxes tainted with either 1 ml of male urine or 1 ml of distilled water into the mother's private compartment. We observed the families from when the pups were 14 days old until they were 34 days old (when they were weaned). We measured the food and water intake of the mother and pups and the weight of the pups daily. We observed the families via continuous time-lapse videotaping of the compartment where the mother and pups interact. When the pups were 27 days old, we began to check the female pups to see when the vagina opened (this event indicates that the female has reached puberty). When we found that a pup's vagina had opened, we weighed her and performed a vaginal smear. We also smeared her every day after that until she was 70 days old to observe her estrus cycle. Using analysis of variance (ANOVA) of all four studies, we determined that for mothers exposed to male rat the mean age of vaginal opening of their pups was one day later than for pups of mothers exposed only to distilled water. Also, there was significantly less variability in the age of vaginal opening in the families exposed to male rat urine. There was, however, no difference in growth between the two conditions. Therefore, the difference in the observed time of vaginal opening was not due to differences in pup growth between the two conditions. The delay of puberty in female pups of mothers exposed to male rat urine is likely due to a pheromone in male rat urine that acts through the mother to cause a delay of puberty in her daughters.  |CURRENT INFO|

1995 REU Mentors:  Dr. Cynthia Langley & Dr. Jeffrey Schank, Department of Psychology (Alberts lab)

The Effects of Carbamazepine on Discrimination Reversal Conditioning and Memory in Rabbits
Past studies have indicated that removal of the hippocampus inhibits learning and memory. Carbamazepine (CPP) is an anti-epileptic drug known to inhibit learning in humans. CPP is known to block NMDA receptors, which the hippocampus is rich in. Thus, it is hypothesized that CPP will have the same effect on learning and memory as an hippocampectomy. In order to test the hypothesis that CPP effects learning and memory, I examined the effects of CPP on discrimination-reversal learning of the classical eye-blink response in rabbits. Classical eye-blink conditioning was evaluated using a tone conditioned stimulus (CS) followed by an air puff unconditioned stimulus (UCS). A different pitch tone was unpaired to the UCS. Acquisition was determined by eye-blink conditioned response (CR) to the CS. After criterion was reached, CPP was infused (intra-ventricularly) during ten sessions of reversal training. If CPP interferes with eye-blink conditioning, I expect to see a failure of the rabbits to reverse during sessions when CPP is infused; a response analogous to the effects of hippocampectomy. The effects of CPP administration will be discussed in terms of NMDA receptors and hippocampal function.  |CURRENT INFO|

1995 REU Mentor:  Dr. Joseph Steinmetz, Department of Psychology | Program in Neural Science (Steinmetz lab)

The Detection and Analysis of Chemical Compounds in Male Norway Rat (Rattus norvegicus) Urine
The focus of our study is the detection and analysis of the volatile chemical compounds in male Norway rat (Rattus norvegicus) urine. These chemical compounds may act as pheromones, which are chemical signals that transmit physiological and behavioral information from one rat to another. Our goal is to identify the similarities and differences in the volatile chemical compounds among the ten male rats used in our study. One 24-hour sample of urine (for purpose of testing) was collected from each of the ten breeded male rates. Urine samples were collected by placing the rats into a metabolism cage. A metabolism cage consisted of a top compartment in which a rat was placed and given ample food and water. The floor of this compartment was permeable which allowed the rat to urinate through the floor, down through a filter and into a glass jar packed in a styrofoam box full of dry ice where the urine was snap frozen (frozen on contact). To analyze the volatile chemical compounds in the urine samples, we will be using the method of capillary gas-chromatography in the chemistry department. We will run three samples (each sample will take about two hours) on each of the ten rats for the purpose of reliability. To estimate the quantity of each volatile in the urine and standardize the three runs on each rat, we will use an internal standard (a fairly water soluble chemical that will elude easily). Capillary gas-chromatography is the method of separation and analysis of mixtures of volatile compounds in which a sample is injected into a high temperature injection port where it is vaporized. From there, a stream of gas called a carrier gas (HE) carries the sample to a column where the solutes are separated by absorption. Then, the stream of gas carrying the separated components passes through a detector designed to respond to solute molecules in the gas phase. Finally, the signals from the detector is recorded over a period of time as a chromatogram. The chromatograms will allow us to statistically determine differences in the quantities of compounds present in each of the ten rats. Thus, we will be able to estimate both the qualitative (presence or absence of a compound) and quantitative variation in volatile compounds. This research will provide basic data required to identify possible pheromones in male rat urine.  |CURRENT INFO|

1995 REU Mentor:  Dr. Jeffrey Schank, Department of Psychology & CISAB (Alberts lab)

The Effects of Phenytoin in the Rabbitt
Two New Zealand male rabbits were classically conditioned to blink to a high pitch tone followed by an air-puff and learned through discrimination not to blink to a low pitch tone which was not reinforced by an air-puff. Once this task was sufficiently learned the rabbits were to be injected with phenytoin, an anti-convulsant drug, for ten days. After the ten days the rabbits were to be conditioned to the two tones to observe the effects of phenytoin on retention of the learning and memory. To date, no rabbits have met the discrimination criterion. I expect that once the criteria has been reached the previously learned eye-blinking will be interrupted when phenytoin is administered.  |CURRENT INFO|

1994 REU Mentor:  Dr. Joseph Steinmetz, Department of Psychology | Program in Neural Science (Steinmetz lab)

Spiny Mice: Foraging and Social Transmission of Information About Food Availability
The central goal of the research is to determine if an animal returning from a successful day of foraging can pass on information about the location of food to the rest of the colony. Bennett Galef, a researchers from McMaster University in Ontario, Canada, performed similar foraging experiments using Norway rats. His findings suggest that the rats were able to encode, store, and retrieve information on the location of food, and this task was performed at a level greater than a chance occurrence. My particular project wants to determine if spiny mice can transmit information concerning the location of food on a four arm radial maze. The first phase of the experiment involved acclimating 16 spiny mice to the maze. This was done by allowing each subject to explore the maze for 20 minutes. Once the mice were acclimated to the maze, I began to train them to learn the location of three treat foods. The criteria used to assess learning was for six consecutive days a subject had to respond correctly on two or more of the last three trials of the training day.  |CURRENT INFO|

1994 REU Mentor:  Dr. Jeffrey Alberts, Department of Psychology & CISAB (Alberts lab)

The Effects of Experience on Response to Female Posture in Male Sticklebacks: Simultaneous vs. Sequential Presentation
No abstract available.  |CURRENT INFO|

1994 REU Mentor:  Dr. William Rowland, Department of Biology (Rowland lab)

Project title and abstract not available.  |CURRENT INFO|

1994 REU Mentor:  Dr. Ellen Ketterson, Department of Biology (Mt. Lake Biological Field Station, VA)

Project title and abstract not available.  |CURRENT INFO|

1994 REU Mentor:  Kathleen Silva, Department of Psychology (Timberlake lab)

Project title and abstract not available.  |CURRENT INFO|

1994 REU Mentor:  Fran Silva, Department of Psychology (Timberlake lab)

Project title and abstract not available.  |CURRENT INFO|

1993 REU Mentor:  Dr. Meredith West, Department of Psychology (West lab)

Project title and abstract not available.  |CURRENT INFO|

1992 REU Mentor:  Dr. John Phillips, Department of Biology (Phillips lab)

Project title and abstract not available.  |CURRENT INFO|

1992 REU Mentor:  Dr. William Timberlake, Department of Psychology (Timberlake lab)

Project title and abstract not available.  |CURRENT INFO|

1991 REU Mentor:  Dr. John Phillips, Department of Biology (Phillips lab)

Molecular Analysis of Learning in Hermissenda
Project abstract not available.  |CURRENT INFO|

1991 REU Mentor:  Dr. Jospeh Farley, Department of Psychology