Spike-Based Population Coding of Interaural Time Difference (ITD).

Abstract

Event Abstract Back to Event Spike-Based Population Coding of Interaural Time Difference (ITD). Adrien Jouary1, 2* and Sophie Deneve1, 2 1 Ecole Normal Supérieure, Département d’Etudes Cognitives, France 2 Ecole Normal Supérieure, Inserm U960, France The interaural time difference (ITD), the difference arrival time of a sound between two ears is the primary auditory cue used by both mammals and birds to localize the source of low-frequency sounds. The minimal ITDs that barn owls or human can perceive (<10s) is two order of magnitude smaller than the duration of an action potential. It represents thus a great challenge in temporal processing. In birds, ITDs are first encoded in neurons of the nucleus laminaris (NL), thought to compute a cross-correlation of inputs from the two ears. However, while initially time-locked to the stimulus and frequency-selective, this information is eventually translated into a representation of object position in the Inferior Colliculus (IC). The neural mechanisms involved in extracting ITDs have been extensively studied, but how these responses are translated into reliable spatial positions remains unclear. To investigate this issue, we implemented a 3 layer neural network, modeling NL, ICX and IC respectively, and acting as an ideal observer. Inputs to the network are band pass-filtered signals mimicking inputs from auditory nerve fibers. Each layer, from model NL cells to ICX to inferior colliculus, performs an optimal Bayesian inference of object position based on information from the layer below. Integrate and fire dynamics and lateral inhibitory connections insure that the posterior probability distribution is optimally encoded in the output spike trains. The network output is a spiking probabilistic population code for position that can be optimally combined with information from other sources, i.e. visual cues in IC. This model reproduces a very large set of experimental results, including cross-correlation in NL, spike trains initially time locked and later asynchronous and Poisson-like, shapes, distribution and variability of ITD tuning curves in the different areas. Moreover, our approach explains how an invariant position can be extracted from different auditory signals (pure tone, noise, clicks…) corresponding to different ITD tuning curves. Each spike is associated with an invariant kernel imposed by the network connections, and decoding corresponds to a sum of these kernels. However, neural responses themselves are strongly stimulus dependent since different types of sounds are variously informative, corresponding to different probability distributions. Keywords: computational neuroscience Conference: Bernstein Conference on Computational Neuroscience, Berlin, Germany, 27 Sep - 1 Oct, 2010. Presentation Type: Presentation Topic: Bernstein Conference on Computational Neuroscience Citation: Jouary A and Deneve S (2010). Spike-Based Population Coding of Interaural Time Difference (ITD).. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.fncom.2010.51.00007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Sep 2010; Published Online: 22 Sep 2010. * Correspondence: Dr. Adrien Jouary, Ecole Normal Supérieure, Département d’Etudes Cognitives, Paris, France, adrien.jouary@ens-cachan.fr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Adrien Jouary Sophie Deneve Google Adrien Jouary Sophie Deneve Google Scholar Adrien Jouary Sophie Deneve PubMed Adrien Jouary Sophie Deneve Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.