Effects of cortical lesions upon the copulatory behavior of male rats.

Abstract

Copulatory behavior in rats was measured before and after lesions to the cortex. Some rats underwent as many as 3 cortical insults. Lesions involved from 1 to 75% of the cortex. Testosterone proprionate was injected in post-operative noncopulators as a control against endocrine disturbance of the sex function. Destruction of from 1 to 19% of the cortex did not abolish copulatory behavior. Lesions of 20 to 75% abolished copulatory behavior in some [male][male]. The % of the noncopulatories was roughly correlated with the size of the lesion. The number of positive tests of copulation was reduced by the cortical lesions and the reduction was roughly related with the amt. of the destruction. Unilateral lesions were less severe than bilateral. Cortical lesions reduce the rat''s responsiveness to sex stimuli without affecting the actual pattern of the sex behavior.