Sensitivity to Interaural Time Differences Conveyed in the Stimulus Envelope

Estimating Inputs of Binaural Neurons Through the Temporal Analysis of Spike Trains

Mathias Dietz*, Le Wang, David Greenberg, David McAlpine

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)313-330
Number of pages18
JournalJARO - Journal of the Association for Research in Otolaryngology
Volume17
Issue number4
DOIs
Publication statusPublished - 1 Aug 2016

Keywords

  • auditory modeling
  • binaural
  • extracellular recordings
  • inferior colliculus
  • interaural time difference

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