Indiana University Bloomington

Neuroscience
Neuroscience
G. Troy Smith

G. Troy Smith

B.S., Cornell University, 1989
Ph.D., University of Washington, 1996
Postdoctoral Fellow, University of Texas, Austin

Email address: getsmith(at)indiana.edu

Research Interests

Research in my laboratory focuses on the neural and hormonal control of behavior. In particular, I am interested in how gonadal steroid hormones, such as testosterone and estradiol, influence the anatomy and physiology of the nervous system to produce sexually dimorphic and seasonally modulated behavior. The main system studied in the laboratory is the electromotor system of weakly electric fish. The electromotor system is a neural circuit that controls the production of weak electrical dischages used by the fish both to locate objects in their environment and to communicate with each other. These electrical signals are often sexually dimorphic and regulated by hormones. The electromotor system contains only 3-4 different types of neurons, and there is a relatively straightforward relationship between the electrophysiological activity of these neurons and the electrical behavior of the fish. The simplicity of this system makes it possible to study how hormone actions on the anatomy and physiology of individual cell types are related to the sexually dimorphic behavior produced by this circuit. Current projects in the laboratory include investigating (1) how neurons in the electromotor circuit produce the rhythmic command signal for electric organ discharges; (2) how hormone effects on the physiology of these neurons results in sexually dimorphic electric communication signals; and (3) how species differences in hormone action and neurophysiology are related to species diversity in sexual dimorphism and behavior. Techniques used in the laboratory include behavioral analysis, hormonal manipulations, neuroanatomy, pharmacology, and electrophysiology. (See also: Smith Lab website) www.indiana.edu/~efishlab/

Representative Publications

Telgkamp, P., Combs, N., and Smith, G.T. (in press, 2007). Serotonin in a diencephalic nucleus controlling communication in an electric fish: Sexual dimorphism and relationship to indicators of dominance. Journal of Neurobiology.

Zhou, M. and Smith, G.T. (2006). Structure and sexual dimorphism of the electrocommunication signals of the weakly electric fish, Adontosternarchus devenanzii. Journal of Experimental Biology, 209:4809-4818.

Smith, G.T., Unguez, G.A., and Weber, C. (2006). Distribution of Kv1-like potassium channels in the electromotor and electrosensory systems of a weakly electric fish. Journal of Neurobiology, 66:1011-1031. (cover article)

Smith, G.T. (2006). Pharmacological characterization of ionic currents that regulate high-frequency spontaneous activity of electromotor neurons in the weakly electric fish, Apteronotus leptorhynchus. Journal of Neurobiology, 66:1-18.

Kolodziejski, J.A., Nelson, B.S., and Smith, G.T. (2005). Sex and species differences in neuromodulatory input to a premotor nucleus: a comparative study of substance P and communication behavior in weakly electric fish. Journal of Neurobiology 62:299-315.

Smith, G.T., Allen, A.R., Gammie, S.C., and Oestreich, J. (2005). Immunohistochemistry for L-citrulline reveals nitric oxide production in nitric oxide synthase-expressing neurons in the electromotor and electrosensory systems of the weakly electric fish, Apteronotus leptorhynchus. Brain Behavior and Evolution 65:1-13.

Smith, G.T., Unguez, G.A., and Reinauer, R.R. Jr. (2002). NADPH-diaphorase activity and nitric oxide synthase-like immunoreactivity colocalize in the electromotor system of four species of gymnotiform fish. Brain Behavior and Evolution.

Zakon, H. H. and Smith, G. T. (2002). Weakly electric fish: behavior, neurobiology, and neuroendocrinology. In: Hormones, Brain, and Behavior (eds. Pfaff, D., Arnold, A., Etgen, A., Fahrbach, S., Moss, R., and Rubin, R.) New York: Academic Press.

Smith, G.T., Lu, Y., and Zakon, H.H. (2000). Parvocells: A novel interneuron type in the pacemaker nucleus of a weakly electric fish. Journal of Comparative Neurology, 423: 427-439.

Smith, G.T. and Zakon, H.H. (2000). Pharmacological characterization of ionic currents that regulate the pacemaker rhythm in a weakly electric fish. Journal of Neurobiology, 42: 270-286.

Smith, G.T. (1999). Ionic currents that contribute to a sexually dimorphic communication signal in weakly electric fish. Journal of Comparative Physiology A, 185: 379-387.