Psychophysics, Physiology and Models of Hearing, pp. 185-194. T. Dau, V. Hohmann, and B. Kollmeier, eds., Singapore, World Scientific, 1999.

Quality of Coincidence Detection and ITD tuning: A Theoretical Framework

R. Kempter, W. Gerstner, H. Wagner, and J. L. van Hemmen

Coincidence detector neurons increase their firing rate significantly if the input changes from random to coherent. Similarly, neurons in the avian nucleus laminaris vary their firing rate as a function of the interaural time difference (ITD). In both cases, neurons transform temporally coded input into a rate-coded output. To characterize the quality of this transformation we define a new measure, which explicitly takes noisy spike output of neurons into account. As an application, we investigate the coincidence detection properties of an integrate-and-fire (I&F) neuron in dependence on internal parameters and input statistics. We show that there is an optimal threshold and, furthermore, that there is a broad range of near-optimal threshold values. The theoretical results are applied to ITD-tuning of neurons in the laminar nucleus of the barn owl.