Joseph E. Steinmetz
Abstracts of Selected Publications

ABSTRACT
Peripherally induced spinal fixation, a relatively long term persistence of postural asymmetry that follows appropriate periods of hindlimb stimulation, appears to be a useful spinal model of memory storage processes in higher levels of the nervous system. The present studies examine two aspects of this form of spinal plasticity. In the first experiment, possible similarities between memory consolidation processes involving intact organism and fixation processes in spinalized rats were examined by application of electroconvulsive shock (ECS) at various time periods during the fixation procedure. Spinal ECS was effective in disrupting retention of the stimulaton-induced postural asymmetry when delivered immediately after 30 min of hindlimb stimulation but not when delivered before, midway through, 20 min after, or 35 min after hindlimb stimulation. These results are similiar to the disruption of memory processes often observed when ECS is delivered during more complex, associative, learning paradigms. In the second experiment, spinal fixation was successfully demonstrated in an isolated, flexor reflex system composed of the tibial (sensory) nerve, spinal cord, and peroneal (motor) nerve. Thirty minutes or more of tibial nerve stimulaton produced substantial poststimulaton increases in evoked whole nerve response amplitude and area. The potentiated response persisted as long as 30 min after stimulation. The present data indicate two important findings regarding fixation of a peripherally induced spinal reflex alteration. First, spinal fixation resembles hypothesized memory consolidation in that both are susceptible to disruption by a strong electrical stimulus when the stimulus is applied during a specific phase of the alteration process. Second, the fixation effect can be obtained in an isolated, polysynaptic reflex system devoid of sensory receptors and muscle effectors. This reduced model preparation seems suitable for future investigations of neurophysiological substrates that underly peripherally induced spinal fixation.

| Faculty   | Adjunct Faculty   | Postdoc/Scientist   | Grad. Students   | CISAB Alumni

| Graduate Program   | Undergrad.Prog.   | REU Program   | Postdoc Info  : Members Only

| Speakers   | Local Calendar   | Conferences   | CISAB Lectures

| DO Stuff !   | GET Stuff !   | LEARN Stuff !   | Good Reads

| Careers   | Homework Help   | Media Resource   | Tech Problems?   | Useful Links

| Contact   | A.B. Bulletin   | © Notice   | Web Site Index