Transducer Motor Coupling in Cochlear Outer Hair Cells

Abstract

Although many lines of evidence point to the outer hair cell as the element which controls basilar membrane mechanics, the precise nature of the interaction within the cochlear partition remains obscure. A minimum requirement of several theoretical models is that any work done by the outer hair cells on the basilar membrane has to occur synchronously with the movement of the membrane (e.g. Neely & Kim, 1986; Giesler, 1986). If so, outer hair cells must generate forces at acoustic rates. Isolated outer hair cells do indeed possess a high frequency motility (Ashmore 1987a), indicating that force is generated at rates too high to involve enzymatic intermediates, but probably based on simple physicochemical mechanisms. If outer hair cells do function to oppose the basilar membrane fluid damping such dynamic forces need to be about three orders of magnitude less than the static deflection forces of the basilar membrane.