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Sensitivity to Interaural Time Differences Conveyed in the Stimulus Envelope: Estimating Inputs of Binaural Neurons Through the Temporal Analysis of Spike Trains.

Authors :
Dietz M
Wang L
Greenberg D
McAlpine D
Source :
Journal of the Association for Research in Otolaryngology : JARO [J Assoc Res Otolaryngol] 2016 Aug; Vol. 17 (4), pp. 313-30. Date of Electronic Publication: 2016 Jun 13.
Publication Year :
2016

Abstract

Sound-source localization in the horizontal plane relies on detecting small differences in the timing and level of the sound at the two ears, including differences in the timing of the modulated envelopes of high-frequency sounds (envelope interaural time differences (ITDs)). We investigated responses of single neurons in the inferior colliculus (IC) to a wide range of envelope ITDs and stimulus envelope shapes. By a novel means of visualizing neural activity relative to different portions of the periodic stimulus envelope at each ear, we demonstrate the role of neuron-specific excitatory and inhibitory inputs in creating ITD sensitivity (or the lack of it) depending on the specific shape of the stimulus envelope. The underlying binaural brain circuitry and synaptic parameters were modeled individually for each neuron to account for neuron-specific activity patterns. The model explains the effects of envelope shapes on sensitivity to envelope ITDs observed in both normal-hearing listeners and in neural data, and has consequences for understanding how ITD information in stimulus envelopes might be maximized in users of bilateral cochlear implants-for whom ITDs conveyed in the stimulus envelope are the only ITD cues available.

Details

Language :
English
ISSN :
1438-7573
Volume :
17
Issue :
4
Database :
MEDLINE
Journal :
Journal of the Association for Research in Otolaryngology : JARO
Publication Type :
Academic Journal
Accession number :
27294694
Full Text :
https://doi.org/10.1007/s10162-016-0573-9