EFFECT OF BILATERAL TEMPORAL CORTICAL ABLATION ON DISCRIMINATION OF SOUND DIRECTION

Abstract

Cats were tested in their responses to the position of a sound which was brief or which was extended for as much as 30 sec. Two tests were used in which the sound source indicated the position of food. Other tests provided information with respect to the animals'' ability to orient to a continuing sound source or follow a moving, unseen sound source. Cats with bilateral lesions of AI, AII and Ep showed evidence of being unable to orient to brief sounds but were partially successful in seeking out the region of the sound if the sound was prolonged. Control cats with damage to the posterior suprasylvian and lateral gyri had no difficulty in orienting to any of the sounds. The interpretation was made that the auditory cortex is necessary for localizing the instantaneous position of a sound. Cats with auditory cortical damage could utilize intensity cues to advantage if the sound is extended in time. The data fit Head''s generalization that the sensory cortex subserves accurate localization of sensations.