A Generalized Van Der Pol-Oscillator Cochlea Model
Over the last decade it has become clear that active and nonlinear behavior of the cochlea is to a certain extent similar to that of a Van der Poloscillator. This was first proposed by Johannesma (1980). It was worked out in more detail by several groups (e.g., van Netten and Duifhuis, 1983, Duifhuis et al., 1985, Jones et al., 1986, Diependaal et al., 1987, van Dijk and Wit, 1988). We have been working on a cochlea model with many active components, i.e. self-sustained oscillators. Initially this was set up with spatial parameters that varied smoothly. The classical parabolic damping profile was used. Our major emphasis, however, shifted toward potentially more realistic biophysical models. For the damping term we now use a function in which two parts can be discerned. First, a passive (positive) part with exponential “tails”, which provides response behavior with a log-like characteristic for external stimuli. Secondly, there is an active (negative) part that, if sufficiently strong, produces net active (negative damping = energy production) behavior. In order to model spontaneous emissions, we also introduced spatial discontinuities in the damping parameters.
KeywordsBasilar Membrane1 Strong Oscillator Spatial Discontinuity Dominant Oscillator Cochlear Partition
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