A flexible anatomic set of mechanical models for the organ of Corti

Abstract

A new model for the mechanical and hydrodynamical processes in the organ of Corti (OoC) is proposed. In this model the motion of the basilar membrane is provided as input, and we concentrate on the other components of the OoC. The model consists of a set of equations, all based on Newton's laws, describing the motions and mutual interactions of the outer hair cells, the outer hair bundles, Deiter cells, the reticular lamina, Hensen cells, and the inner hair bundle. In addition, the model includes the equations describing the endolymph fluid motion in the subtectorial channel. Key ingredients in the model are the nonlinear constitutive laws governing the vibrations of the outer hair bundles and outer hair cells. The inner hair bundle oscillates via interaction with the endolymph flow. It is shown that under a minimal set of assumptions, and using basic mechanical principles, the components of the OoC listed above can act as a second filter, along with the basilar membrane filter, that enhances frequency selectivity, amplitude compression and signal to noise ratio.cochlea | hair cell | second filter | critical oscillator

Reduced equations for an active model of the hydroelastic waves in the cochlea

“…It is interesting to note here that after oscillations in the perilymph fluid are transformed as described above into mechanical vibrations of the BM, these vibrations are transformed via a complex set of interactions in the Organ of Corti into oscillations in the endolymph, which then set the inner hair cells into motion, thus activating the auditory nerve. It was recently conjectured [2] that this further transformation from solid back to viscous fluid vibrations involves a second filter. We wonder whether one benefit of this second filter is to suppress the spurious oscillations of the BM.…”