Dept. of Elec. Eng. Systems, Faculty of Eng., Tel Aviv Univ., Tel Aviv 69978, Israel
The role of the outer hair cells as cochlear amplifiers has been recently shown experimentally and theoretically. The nonlinear transmission line model was chosen as a framework to test the role of the cochlear amplifiers to different cochlear properties. It was found that there are phenomena such as rate suppression, or threshold microstructure in the vicinity of spontaneous otoacoustic emission, that can be predicted by such a model only if it is assumed that the local cochlear amplification is dynamically changing as a function of the stimulus. The dynamics of the cochlear amplifiers was achieved in the model by assuming that each outer hair cell amplification gain depends on the electrical potential across its membrane. It is most probable that the cochlear microphonics, which represent the potential changes in the scala media, are indication to the electromechanical feedback loop. The electrical potential in the model is derived by assuming that it produces an external mechanical force that is applied to the outer hair cells that in return act as a damped-spring mass. The model was simulated in the time domain, and its prediction to various cochlear phenomena will be discussed.