Application of a point process model to responses of cat lateral superior olive units to ipsilateral tones.

A general point process theory is developed to describe discharges recorded from lateral superior olivary units of the cat responding to ipsilaterally presented tone bursts and continuous tones. Statistical analysis of the stationary portion of the sequence of interspike intervals demonstrated that, for most units, the duration of each interval is statistically dependent only on the duration of the previous interval. A specific point process model is derived based on this analysis to describe the measured serial dependence as well as the deadtimes observed in interval histograms. The statistical dependence is well described as a shift of the interspike interval distribution, the shift depending on the duration of the previous interval. This model is then used to simulate the initial chopping in the tone burst responses. It is concluded that chopping responses and serial dependence do not result from properties of the unit's inputs; rather, they are consequences of the inherent characteristics of the unit.