Strategies for Encoding ITD in the Chicken Nucleus Laminaris

Abstract

Animals, including humans, use interaural time differences (ITDs) that arise from different sound path lengths to the two ears as a cue of horizontal sound source location. The nature of the neural code for ITD is still controversial. Current models advocate either a map-like place code of ITD along an array of neurons, consistent with a large body of data in the barn owl, or a ratebased population code, consistent with data from small mammals. Recently, it was proposed that these different codes reflect an optimal coding strategy that depends on head size and sound frequency. The chicken makes an excellent test of this hypothesis because its physical features are similar to small mammals, yet it shares a more recent common ancestry with the owl.