Role of sensory deficits in motor impairments after injury to primary motor cortex.
After a focal ischemic lesion in the hand representation of the primary motor cortex in squirrel monkeys, manual skill was mildly and transiently impaired on a reach-and-retrieval task. Performance was significantly poorer during weeks 1 and 3 post-lesion, but was normal by week 4. An unusual behavioral event was also observed after the lesion. Monkeys reached for pellets, but visually inspected the hand for the presence of the pellets, even when none were actually retrieved. This behavior, possibly indicative of a sensory deficit, was rarely observed prior to the lesion, but was observed at significantly higher levels during week one post-lesion. These results suggest that the primary motor cortex plays a significant role in somatosensory processing during the execution of motor tasks. Motor deficits heretofore identified as purely motor, may be at least partially due to a sensory deficit, or sensory-motor disconnection.
Nudo
R J
RJ
Center on Aging and Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City 66160, USA. rnudo@kumc.edu
Friel
K M
KM
Delia
S W
SW
D000704:Analysis of Variance; D000818:Animals; D001132:Arm / Q000503:physiopathology; D001522:Behavior, Animal / Q000502:physiology; D002545:Brain Ischemia / Q000503:physiopathology; D001931:Brain Mapping; D002544:Cerebral Infarction / Q000503:physiopathology*; D005260:Female; D006225:Hand / Q000503:physiopathology*; D007858:Learning / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D012453:Saimiri; D012678:Sensation Disorders / Q000503:physiopathology*; D014110:Touch / Q000502:physiology