Neural Mechanism of Binding ITD Information with IID One for Generating Brain Map of Sound Localization

Abstract

Barn owls perform sound localization based on analyses of interaural differences in arrival time and intensity of sound. Two kinds of neural signals representing the interaural time difference (ITD) and the interaural intensity difference (IID) are processed in parallel in anatomically separate pathway. We explain briefly the neural models of pathways of ITD and IID detection which we have already presented [1,2]. We present a neural network model of ICc ls in which the signals representing ITD and IID are first combined with each other. It is shown using our neural models how the neural map, in which ITD and IID are represented along the axes being perpendicular mutually, can be generated in ICc ls by the excitatory inputs from ICc core representing ITD and the inhibitory inputs from bilateral VLVps representing IID. We show that the firing rates of ICc ls neuron are well represented by a suppressive multiplication of ITD and IID inputs. This seems to be the origin of the multiplicative binding found in ICx by Pena and Konishi [3].