SHARPENING OF FREQUENCY TUNING BY INHIBITION IN THE CENTRAL AUDITORY-SYSTEM - TRIBUTE TO YASUJI-KATSUKI

Frequency analysis is a fundamental function of the auditory system, B ekesy and Katsuki believed that sharpening of frequency tuning by late ral inhibition takes place in the central auditory system, However, mo st 'cat' auditory physiologists have believed that frequency tuning of neurons is not sharpened in the central auditory system, so that ther e is no lateral inhibition. Unlike quasitriangular frequency-tuning cu rves of peripheral neurons, pencil- or spindle-shaped frequency-tuning curves have been found in the central auditory systems of many specie s of animals belonging in different classes, Inhibitory tuning curves are commonly associated with such 'level-tolerant' sharp excitatory tu ning curves. It is clear that frequency-tuning curves of some central auditory neurons are sharpened by inhibition, Yasuji Katsuki (Professo r, M.D., Ph.D.) passed away on 6 March 1994 at the age of 88. I have w ritten this article as a tribute to him, focusing on his major contrib ution to auditory neurophysiology: the finding of the sharpening of fr equency tuning in the cat's central auditory system, Neural sharpening of frequency tuning is an old yet still current topic, as you will re ad in this article dedicated to Professor Katsuki.