Cortical correlates of auditory localization and of related perceptual phenomena.

Abstract

Electrophysiological responses were recorded at the auditory cortex of anesthetized cats. The stimulus conditions duplicated those of psychophysical experiments on auditory localization. The 2 ears were stimulated independently with clicks differing in time of arrival or in intensity. The cortical responses were found to parallel in several respects the perceptual phenomena which occur under the same stimulus conditions: (1) under the stimulus conditions that cause a sound to be heard at one side of the head, the cortical activity is greater at the contralateral cerebral hemisphere. (2) The further over to the side the sound is heard, the greater is the difference between the activity at the 2 hemispheres. (3) When the sound is heard in the median plane, the cortical activity is equal at the 2 hemispheres. Cortical correlates were also found for 2 related perceptual phenomena[long dash]perceptual fusion of closely successive clicks and enhanced loudness of the second of 2 clicks.