Investigating the implications of outer hair cell connectivity using a silicon cochlea

In this paper we present results from several implementations of silicon cochleae whose dynamics are governed by the Hopf equation. These silicon cochleae exhibit the majority of active, nonlinear characteristics of the biological cochlea such as large-signal compression, two-tone suppression, the creation of distortion products and so forth. Here we explore the coupling between resonant sections of the basilar membrane to investigate phenomena such as masking and the characteristic frequency response curve of the cochlea at a particular place along the basilar membrane. We see that the interaction of resonant sections can account for these phenomena and that we can use these observations to partially explain the connectivity of the afferent and efferent fibres to the outer hair cells. This work not only gives us valuable insight into the dynamical behaviour of the early auditory system but it also highlights the benefits of building circuits of these complex systems in order to produce models whose parameters can be tuned and whose outputs can be observed and measured in real-time.