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

  • Mathias DietzEmail author
  • Le Wang
  • David Greenberg
  • David McAlpine
Research Article


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.


binaural interaural time difference inferior colliculus extracellular recordings auditory modeling 



This work was funded by the European Union under the Advancing Binaural Cochlear Implant Technology (ABCIT) grant agreement (No. 304912). We thank Torsten Marquardt for his valuable contributions and three anonymous reviewers for their very helpful comments and suggestions.

Compliance with Ethical Standards

Conflict of Interests

The authors declare that they have no conflict of interest.


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Copyright information

© Association for Research in Otolaryngology 2016

Authors and Affiliations

  • Mathias Dietz
    • 1
    • 2
    • 3
    Email author
  • Le Wang
    • 4
  • David Greenberg
    • 2
  • David McAlpine
    • 2
    • 5
  1. 1.Medizinische Physik and Cluster of Excellence Hearing4allUniversität OldenburgOldenburgGermany
  2. 2.UCL Ear InstituteLondonUK
  3. 3.National Centre for Audiology, Faculty of Health SciencesWestern UniversityLondonCanada
  4. 4.Center for Computational Neuroscience and Neural TechnologyBoston UniversityBostonUSA
  5. 5.Dept. of Lingustics, Australian Hearing HubMacquarie UniversitySydneyAustralia

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