Neurophysiological studies on hearing in goldfish.

Abstract

Studies were made on hearing in goldfish, an ostariophysian fish, by recording microphonic potentials as well as nerve responses with micro-electrodes. The microphonic potential of the sacculus, fish''s main hearing organ, was evoked at twice the frequency of the sound. Moreover, it showed a remarkable regional difference; response to the compression phase of the sound predominated when recorded in the dorsal part of the saccular macula, while response to the rarefaction phase predominated in the ventral part. These results were attributed to the presence of 2 sets of hair cells of opposite orientation, each occupying dorsal and ventral part of the macula. Unitary action potentials were recorded from three kinds of afferent fibers, 2 from the sacculus and 1 from the lagena. Discharges in these fibers were set up in synchronization with the sound wave. Intracellular recording from large fibers that arise from the anterior part of the saccular macula disclosed that each afferent discharge in these fibers was preceded by a generator potential. The generator potential was graded and appeared with a delay of about 0.5 msec. after the microphonic potential, suggesting a chemical nature of transmission between hair cells and 8th nerve fibers.