CONTRIBUTION OF AUDITORY CORTEX TO ACOUSTICAL ORIENTATION IN CATS UNDER CONDITIONS OF DISCORDANT AUDITORY REAFFERENCE. Ralph E. Beitel. Institution: Coleman Laboratory, Department of Otolaryngology, University of California, San Francisco, CA 94143.
APStracts 4:0243N, 1997.
ABSTRACT
Head orienting responses (ORs) evoked by a stationary source of sound typically terminate in small undershoots in normal hearing cats or in large undershoots (hypometria) if the auditory cortex is ablated bilaterally (Beitel and Kaas 1993). In the present study, ORs executed by cats were studied using a procedure in which the OR produced an isogonal rotation of the sound source, i.e., response-produced change (reafference) in the acoustic stimulus was distorted. Under this condition (discordant auditory reafference), ORs terminated in large overshoots (hypermetria) in the normal hearing cats. This result indicates that experimental distortion of response-produced auditory feedback resulted in an "on-line" modification of ORs by the normal hearing cats. In the cats with auditory cortex ablated, ORs terminated in large undershoots (hypometria), suggesting that auditory cortex is a necessary component of the central auditory system for processing reafferent acoustic stimuli that normally occur during head rotation in a sound field. 

Received 11 June 1997; accepted in final form 10 September 1997.
APS Manuscript Number J486-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997