Stefan Krol
Margaret F. Cheesman
Donald G. Jamieson
Hear. Health Care Res. Unit, Univ. of Western Ontario, Elborn College, London, ON N6G 1H1, Canada
A mathematical model is described for mechano-electro-chemical transduction in hair cells. The model relates the displacement of stereocilia to the intensity of firing of fibers attached to each hair cell through a cascade of four stages. The gating stage relates hair bundle displacement to the change in conductivity of the hair cell membrane. It is described by a mechanical version of the Hodgkin--Huxley model. The electric stage relates the change in conductivity to the receptor potential through a hair cell electrical network of the Davis type. The calcium kinetics stage relates free calcium ion (Ca[sup 2+]) concentration in hair cells to the receptor potential. It is assumed there are two states of calcium ions: free and bound (by buffers). The synaptic transmission stage relates free calcium concentration to the intensity of firing as described by the Hill equation. Using relevant parameters, the model simulates the behavior of low- and high-spontaneous firing rate fibers, and is being implemented as a component of a complete cochlear model. [Work supported by NSERC, URIF, and Unitron.]