Binaural intensity comparison in the echolocating bat using synaptic conductance

The lateral superior olive is the first neural area to receive binaural inputs in the mammalian sound localization pathway. Selective to interaural level differences (ILD) while intensity-independent, these neurons signal when a sound arrives from within a limited range of angles. Although several different computational models have been proposed to explain ILD-selectivity, we highlight one that has the greatest utility in bat echolocation. We argue for a detection mechanism based on the ratio of excitatory and inhibitory synaptic conductances. An analog VLSI neuron performing this computation in an echolocation system is demonstrated with realistic echolocation signals.