MOTOR RESPONSE TO STIMULATION OF CEREBRAL CORTEX IN ABSENCE OF AREAS 4 AND 6 (MACACA MULATTA)

Abstract

The cerebral cortices of 5 Macaca mulatta were stimulated after previous removal of areas 4 and 6. Four of these had been operated upon in infancy, the 5th when nearly adult. There were marked differences in the responses to stimulation of the 2 types. Those operated upon in infancy had cortices with greater excitability in the regions surrounding the extirpated areas. The response to adequate stimulus was always greater and more diffusely spread in this group of animals. The animal operated upon after maturity had also some regions from which responses could be obtained. In neither group was any region found to be excitable other than those known to be excitable in the intact cortex.