EFFECT OF BILATERAL DESTRUCTION OF THREE LATERAL CEREBRAL CORTICAL AREAS ON CORRECT CONDITIONED DIFFERENTIAL RESPONSES FROM GENERAL CUTANEOUS STIMULATION

Abstract

The purpose of this paper was to determine the effect of 3 lesions, made by extirpation and ther-mo-coagulation and designated as A, B and C on correct conditioned differential responses of a foreleg with 2 different sets of general cutaneous stimuli. In the first set of tests, the positive and negative conditioned stimuli consisted of stroking the back with a hand brush once/sec. with and against the grain. In the 2d set of tests, based on timing, the positive and negative conditioned tests consisted of stroking the back with the grain once/sec. and 3 times/sec. Lesions A and B destroyed Woolsey and Walzl''s first and second auditory areas and lesion C destroyed Tunturi''s third auditory area or Woolsey''s second tactile afferent center. Bilateral lesions A and B, previously reported to be very effective in disrupting the usual association circuits for evoking correct conditioned differential responses with sound, permitted the circuits for eliciting correct responses with general cutaneous sense to function perfectly. Lesion C on both sides prevented the appearance of correct responses for 836-927 trials for the with and against tests and a lesser number of trials later for the slow and fast tests. Bilateral lesions B and C, while producing no effect on the positive conditioned reflex, abolished correct responses with both sets of general cutaneous stimuli for a very long and intensive period of training. It did not, however, prevent correct responses with 2 different sets of sound stimuli. The exact place where lesions C or B and C interrupted the circuits for making correct responses with these general cutaneous tests is not known. The chief defect from the lesions was inability to hold foreleg flexion during a negative conditioned test. This involved correct inhibition.