Effects of static bending of sensory hairs on sound reception in the goldfish

Abstract

1. Effects of static pressure changes on sound reception were studied with neurophysiological techniques in goldfish. Static pressure changes were applied on the fish's abdomen in order to make the saccular otolith deviate from its normal position. 2. Microphonic potentials as recorded with microelectrodes from the saccularmacula were evoked at twice the frequency of the sound. When the pressure on the abdomen was increased, peaks of the microphonic that corresponded tothe compression phase of the sound were augmented and those which corresponded to the rarefaction phase were suppressed. The effect of a decrease of the pressure took place in an opposite direction. 3. Action potentials were recorded intracellularly from single saccular nerve fibers. Effects of pressure changes on the activity of these fibers were different depending on the direction of the pressure change and on the response type of individual nerve fibers. 4. One type of fiber responded with graded depolarization only to an increase of the pressure but did not respond to its decrease. When sound stimulus was applied with pressure changes, response of the fiber to sound stimulus was facilitated during a rise of the pressure, but it was suppressed during a pressure decrease. There were also fibers that responded only to a decrease of the pressure. Behavior of these fibers was just the opposite to that described above. 5. The other type of fibers responded to both an increase and a decrease of the pressure. They correspond to fibers that set up discharges at a rate twice the frequency of the sound. In this type of fibers, responses to the compression phase of the sound were facilitated and responses to the rarefaction phase were suppressed during a rise of the pressure. A decrease of the pressure produced an opposite effect. 6. Mechanisms of interaction between pressure changes and sound stimuli were discussed. © 1967, PHYSIOLOGICAL SOCIETY OF JAPAN. All rights reserved.