Single modeled neuron selective for interaural level differences (ILD). The neuron’s sigmoid selectivity function is similar to neurons in the lateral superior olive (LSO), although ‘labels’ for left and right hemisphere activities are reversed here due to contralateral projections from the LSO to the midbrain.
Modeled neuron populations are equally spaced so that, in this example, activity half-maxima (activity level = 0.5) are achieved at ILDs ranging from -24 to 24 dB in both hemispheres. This range is more than sufficient for representing the vast majority of ILDs encountered under naturalistic conditions, as illustrated by frequency-specific distributions of ILDs in the top right panel, similar to those described here. This range is also sufficient to assure that minimal and maximal activity levels (0.0 and 1.0, respectively) are evoked in peripheral neurons, which is necessary for defining a consistent half-maximal activity level.
Activity patterns obtained across a sub-population of five modeled neurons by recurrent ILD values: -12, -6, 0, 6, or 12 dB.