Nonlinear dynamics of the organ of Corti, modeling both outer hair cell somatic motility and hair bundle motility

Abstract

One of the principal questions in the cochlea biophysics is the determination of relative contributions of the two active processes, OHC somatic motility and HB motility, to the mechanics of the cochlea. Because of the difficulty of eliminating one mechanism without affecting the other, an unambiguous in vivo measurement differentiating their effects remains elusive. Theoretical models, therefore, have been used as one way to examine the contributions of the two active mechanisms to cochlear mechanics. In this paper, we use a physiologically based model of the mammalian organ of Corti to study the hearing active process and the relative contributions of these active forces. This local model integrates the electrical, acoustic, and mechanical elements of a cross section of the cochlea. The nonlinear dynamics of this model are studied with a special emphasis on the regions of stability and the amplification of the mechanical response arising from the active processes. [Work supported by NIH-NIDCD R01-04084 and NIH NIDCD-T32-000011.]