Model for mechanical to neural transduction in the auditory receptor

Abstract

We describe a model for transduction of displacement of the basilar membrane to activity of auditory nerve fibers. The model is physiologically oriented. Quanta (“vesicles”) are added to a population inside an urn (hair cell) at a fixed average rate. They are removed from the population with a probability proportional to the number of quanta in the population and related in a simple manner to the instantaneous amplitude of the input signal (displacement). The removal of a quantum results in an event (action potential) with a probability related to time elapsed since the preceding event (refractory period). Apart from refractoriness, the model is completely specified by three parameters which determine spontaneous and maximum firing rates and the time constant of recovery after intense stimulation. The model is more compatible with observed activity of the auditory nerve than threshold‐crossing models. An important feature of auditory‐nerve data reproduced by the model is the level normalization observed at moderate to high stimulus intensities. The model reproduces features of period, PST, and interval histograms in response to pure and complex tones, tone bursts, and noise. We present results both from analysis and from computer simulation of the model.