Modeling 3-D deformation of outer hair cells and their production of the active force in the cochlea

 We analyze the deformation of the outer hair cell and its production of active force under physiological conditions. The active force has two components. One results from the strain caused by loading in the organ of Corti in the cochlea and depends on the level of the acoustic signal; the other is related to the intrinsic active properties of the cell membrane. We demonstrate our approach by considering, as a basic model of an outer hair cell in the organ of Corti, a cylindrical shell that is filled with an incompressible fluid and located between two planes that move relative to each other. These planes represent the basilar membrane and tectorial membrane complexes. We show that the deformed state of the cell has a 3-D nature, including bending and twisting components. This is different from the experimental conditions in which the active force is usually measured. We estimate the active force as a function of the relative position of the planes, angle of the cell's inclination, and the cell length. Received: 25 October 2001 / Accepted: 30 May 2002 We thank Drs. Aleksander Popel and William Brownell for constructive discussions of the results. This work was supported by research grants DC02775 and DC00354 from NIDCD and AG014748 from NIA.