Velocity and displacement responses in auditory-nerve fibers.

With the help of nonsiniusoidal acoustic stimuli, it is demonstrated that most fibers of the auditory nerve respond to both displacement and velocity of the basilar membrane. Except at very high stimulus levels, motion and displacement toward scala tympani produce excitation; motion and displacement toward scala vestibuli produce inhibition. The displacement and velocity responses interact. When both are excitatory or inhibitory, they reinforce each other; when they are of opposite nature, a partial cancellation occurs. The presence of both displacement and velocity responses in the single fibers suggests that outer and inner hair cells of the cochlea interact.