All Three Rows of Outer Hair Cells Are Required for Cochlear Amplification

Figure 7

Schematic of the fluid-structure interaction using a staggered approach. In Step , initial pressure is applied to the model of the OC and the velocity vector of the OC is obtained. Then, applying this obtained velocity vector to the SV, ST, and subtectorial space as a fluid velocity vector over a fluid-structure interface, the pressure in the SV, ST, and subtectorial space caused by the movement of the OC is obtained. Next, the forces exerted on the TM and RL caused by the shear motion between the TM and RL and are obtained by (15) and (16). In Step , the displacement amplitude of the OHC stereocilia is calculated. Substituting this obtained value into (18), is determined, and thus is determined by (19). is then applied to nodes in the OC model corresponding to the apical and basal ends of the OHC as the force vector . The previously obtained pressure and the initial pressure in time step 2 and the force vectors , , and are applied to the OC. By repeating the above procedure, the displacement amplitudes of the OC and those of the stereocilia at a specific stimulus frequency and a specific stimulus intensity are obtained.