Some possible relations between cochlear neural responses and mechanical parameters of the organ of Corti

Abstract

At preceding meetings we showed that a model of cochlear mechanics, which includes a resonance of the hair-cell stereocilia loaded with the tectorial membrane, can simultaneously account for the observed typical response characteristics of the basilar membrane and of the cochlear-nerve fibers. In this paper we demonstrate that the low-frequency radial displacement magnitude of the tectorial membrane relative to that of the reticular lamina at the location of the inner hair cells can not only determine the phase of the low-frequency fiber responses but also the shape of the neural tuning curves. Specifically, the shape of tuning curves encountered in Mongolian gerbils is associated with a scala-tympani excitatory response phase, in agreement with experimental evidence. A few tuning curves of cat fibers suggest an opposite polarity. This seems to be more generally true after kanamycin treatment. Effects of stereocilia and tectorial membrane damping are also investigated.