EMERGENCE OF RADIAL NERVE DOMINANCE IN "MEDIAN NERVE CORTEX" AFTER MEDIAN NERVE TRANSECTION IN AN ADULT SQUIRREL MONKEY. Schroeder, C. E., S. Seto and P.E. Garraghty. Departments of Neuroscience and Neurology, Albert Einstein College of Medicine, Bronx, NY and Program in Neural Science, Department of Psychology, Indiana University, Bloomington, IN.
APStracts 3:0243N, 1996.
1. Corepresentation of nondominant radial nerve inputs with the dominant (median or ulnar nerve) inputs in the glabrous hand surface representation provides a likely mechanism for reorganization after median nerve section in adult primates. 2. To examine this issue, we conducted repeated recordings using an implanted linear multielectrode array straddling the laminae at a site in "median nerve cortex" (i.e., at a site with a cutaneous receptive field on the volar surface of D2, and thus, with its dominant afferent input conveyed by the median nerve) in an adult squirrel monkey. 3. We characterized the baseline responses to median and radial nerve stimulation, then cut the median nerve and semi-chronically monitored radial nerve and median nerve (proximal stump) evoked responses. 4. The radial nerve response in median nerve cortex changed progressively over the weeks following median nerve transection, ultimately assuming the characteristics of the dominant nerve profile. During this time, median and ulnar nerve profiles displayed little or no change.

Received 8 August 1996; accepted in final form 17 October 1996.
APS Manuscript Number J632-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996