Cochlear micromechanics—A physical model of transduction

Abstract

The mechanical action of hair-cell transduction, specifically the discrepancy between mechanically measured tuning of basilar membrane motion and neurally measured tuning, is considered. The difference between these 2 measures appears accounted for by a specific, physically motivated, micromechanical model. This model gives rise to a spectral 0, which is identified as the 2nd-filter of cochlear transduction. For high-frequency fibers this 0 resides at a fixed frequency ratio below CF (characteristic frequency); for fibers having low-frequency CF the 0 appears to go to 0 frequency faster than CF. A mechanical model is presented. A possible specific physical realization for the nonlinearity of cochlea mechanics is discussed. The nonlinear model is based on dynamical variations in outer hair cell stereocilia stiffness.