A pitch encoding model based on the intrinsic oscillation circuit: Effects of the time constant and input stimulus types

Many temporal models for pitch perception have adopted a configuration of "delay-lines and coincidence detectors" after the cochlear filtering. Autocorrelation functions are a usual way of its implementation. However, a series of experiments by the authors' group have revealed that the perceived pitch would shift upwards by the effect of aging. Because the autocorrelation simply represents the time intervals statistics in the physical domain, the aging cannot affect this statistics. Therefore, a further pitch encoding process where the physical (physiological) temporal intervals are mapped against any internal reference in the brain. We propose a model comprised of bank of self-oscillatory circuits and the coincidence detectors. The periods of oscillations are intrinsic characteristics of the neural circuit. The proposed model could pick up the fundamental periods of a various types of stimuli, i.e., pure tones, missing fundamentals and iterated ripple noises. To check an effect of aging, the changes in t...