Article date: 1991/11/25
PubMed ID: 1791999
Journal name: Neuroscience letters (ISSN: 0304-3940)
We report changes in the performance of a prehension task in the cat following focal inactivation of the rostrolateral subregion of the distal forelimb area of motor cortex (MCx) produced by muscimol microinjection. Animals reached into a cylindrical target to retrieve a morsel of food. Movements consisted of distinct lift and forward thrust phases following which the food was grasped and retrieved. In separate blocks of trials an obstacle was inserted in the path of the limb. Impact evoked an immediate compensatory trajectory change to bypass the obstruction and, on subsequent trials, an adaptive trajectory change to avoid impact. Inactivation produced three major defects: (1) uncompensated aiming biases to a location above the target; (2) loss of coordination of the grasp and food retrieval; and (3) impairment in trajectory adaptation to avoid impact of the limb with an obstacle. Thus, focal inactivation of the distal forelimb area of MCx produced disordered control of all forelimb joints. The impairment in trajectory adaptation and failure to compensate for aiming biases suggests that the MCx is important in motor learning.
Author List: Martin J H, Ghez C
Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Muscimol;
Mesh terms: Animals; Cats; Cerebral Cortex/anatomy & histology; Forelimb/physiology; Microinjections; Motor Cortex/physiology; Muscimol/administration & dosage; Muscle Contraction/physiology; Neural Pathways/drug effects; Psychomotor Performance/physiology;