Reorganization of Movement Representations in Primary Motor Cortex Following Focal Ischemic Infarcts in Adult Squirrel Monkeys. Randolph J. Nudo and Garrett W. Milliken. Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, TX 77030.
APStracts 3:0032N, 1996.
1. Intracortical microstimulation (ICMS) techniques were used to derive detailed maps of distal forelimb movement representations in primary motor cortex (area 4) of adult squirrel monkeys before and a few months after a focal ischemic infarct. 2. Infarcts caused a marked but transient deficit in use of the contralateral hand, as evidenced by increased use of the ipsilateral hand, and reduced performance on a task requiring skilled digit use. 3. Infarcts resulted in a widespread reduction in the areal extent of digit representations adjacent to the lesion, and apparent increases in adjacent proximal representations. 4. We conclude that substantial functional reorganization occurs in primary motor cortex of adult primates following a focal ischemic infarct, but at least in the absence of post-infarct training, the movements formerly represented in the infarcted zone do not reappear in adjacent cortical regions.

Received 25 September 1995; accepted in final form 29 January 1995.
APS Manuscript Number J636-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 14 February 96