Tectorial membrane: a possible sharpening effect on the frequency analysis in the cochlea.

Excitation of cochlear hair cells is believed to be produced by radial deflection of their stereocilia as a result of shear motion between the reticular lamina and the tectorial membrane. The shear motion must depend on the mechanical coupling between the organ of Corti and the tectorial membrane. It is shown that, because longitudinal stiffness of the tectorial membrane, the shear motion must be enhanced as the wavelength decreases toward the cochlear vibration maximum. The resulting sharpening of the vibration maximum agrees with the frequency selectivity found in the inner hair cells and cochlear-nerve afferents.