Frequency Selectivity, Adaptation, and Suppression in Goldfish Auditory Nerve Fibers

The acoustic portions of the fish ear are otolith organs (the saccule, lagena, and in some species, the utricle), which are specialized to respond to acoustic energy in the frequency range from below 100 Hz to 2 to 3 kHz in some species. These organs contain a sensory epithelium, made up of type II hair cells, a solid calcium carbonate otolithic stone, and an otolithic membrane intervening between the hair cell cilia and the otolith. In most fish species, sound can reach the ear and cause a displacement of the hair cell cilia through at least two pathways; a direct route through which acoustic particle motion is detected by the otolithic organs operating in an inertial “accelerometer” mode, and an indirect route through which the motion of a gas sac (e.g. swimbladder), as it expands and contracts with the sound pressure waveform, is efficiently transmitted to the ear. See Fay and Popper (1980) for a general review of fish hearing.