Evidence for cue-independent spatial representation in the human auditory cortex during active listening

Nathan C. Higgins, Susan A. McLaughlin, Teemu Rinne, G. Christopher Stecker

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Few auditory functions are as important or as universal as the capacity for auditory spatial awareness (e.g., sound localization). That ability relies on sensitivity to acoustical cues - particularly interaural time and level differences (ITD and ILD) - that correlate with sound-source locations. Under nonspatial listening conditions, cortical sensitivity to ITD and ILD takes the form of broad contralaterally dominated response functions. It is unknown, however, whether that sensitivity reflects representations of the specific physical cues or a higher-order representation of auditory space (i.e., integrated cue processing), nor is it known whether responses to spatial cues are modulated by active spatial listening. To investigate, sensitivity to parametrically varied ITD or ILD cues was measured using fMRI during spatial and nonspatial listening tasks. Task type varied across blocks where targets were presented in one of three dimensions: auditory location, pitch, or visual brightness. Task effects were localized primarily to lateral posterior superior temporal gyrus (pSTG) and modulated binaural-cue response functions differently in the two hemispheres. Active spatial listening (location tasks) enhanced both contralateral and ipsilateral responses in the right hemisphere but maintained or enhanced contralateral dominance in the left hemisphere. Two observations suggest integrated processing of ITD and ILD. First, overlapping regions in medial pSTG exhibited significant sensitivity to both cues. Second, successful classification of multivoxel patterns was observed for both cue types and - critically - for cross-cue classification. Together, these results suggest a higher-order representation of auditory space in the human auditory cortex that at least partly integrates the specific underlying cues.

Original languageEnglish (US)
Pages (from-to)E7602-E7611
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number36
DOIs
StatePublished - Sep 5 2017

Keywords

  • Auditory space
  • Binaural cues
  • FMRI
  • Human auditory cortex
  • Sound localization

ASJC Scopus subject areas

  • General

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