A model of perceptual segregation based on clustering the time series of the simulated auditory nerve firing probability

This paper introduces a model that accounts quantitatively for a phenomenon of perceptual segregation, the simultaneous perception of more than one pitch in a single complex sound. The method is based on a characterization of the time-varying spike probability generated by a model of cochlear responses to sounds. It demonstrates how the autocorrelation theories of pitch perception contain the necessary elements to define a specific measure in the phase space of the simulated auditory nerve probability of firing time series. This measure was motivated in the first instance by the correlation dimension of the attractor; however, it has been modified in several ways in order to increase the neurobiological plausibility. This quantity characterizes each of the cochlear frequency channels and gives rise to a channel clustering criterion. The model computes the clusters and the pitch estimates simultaneously using the same processing mechanisms of delay lines; therefore, it respects the biological constraints in a similar way to temporal theories of pitch. The model successfully explains a wide range of perceptual experiments.