Inner Ear — Cochlear Mechanics and Cochlear Potentials

Abstract

A wide range of acoustic frequencies and amplitudes present in the motion at the footplate of the stapes are analyzed and encoded in the cochlea for transmission to the central nervous system as all-or-none impulses in the fibers of the auditory nerve. Although amplitudes of the mechanical motions are incredibly small and the neurons do not sustain response rates greater than about 200–300 impulses/sec, we can with relative ease hear the musical lines of a single instrument in a symphony orchestra, decode the complex acoustic signals in speech, and recognize the speaker’s voice. The goal of this chapter is to summarize and, when possible, to organize a selected set of observations on the mechano-electric events that occur between the acoustic input at the stapes and the excitation of, or the control of, impulses in the auditory nerve.