Figure 1.

Determination of ILD discrimination threshold of an LSO neuron (unit 110–24). A, Mean discharge rate (•) and SD (○) of an LSO neuron to variations in the ILD of a 300 ms duration CF (16 kHz) tone. The black line shows the best-fitting sigmoid to the rate and the gray line shows the SD computed from the fitted power function of the rate (inset). The inset shows the variance of the rate as a function of the rate on double-log coordinates along with the best-fitting power function (dashed line). B, Example of computing threshold ILD via standard separation metric, D (see definition in Materials and Methods), as a function of increment ILD from the pedestal. The threshold for discrimination was defined as the smallest increment ILD that results in D of 1. C, ILD thresholds as a function of pedestal ILD for the neuron in A. D, A magnified view of C, which delineates three points of interest: the best threshold, corresponding to the minimum of the function, the pedestal ILD at the best threshold, and the threshold at midline, corresponding to pedestal ILD of 0 dB.