Human auditory cortical processing of changes in interaural correlation

Maria Chait, David Poeppel, Alain De Cheveigné, Jonathan Z. Simon

Research output: Contribution to journalArticle

Abstract

Sensitivity to the similarity of the acoustic waveforms at the two ears, and specifically to changes in similarity, is crucial to auditory scene analysis and extraction of objects from background. Here, we use the high temporal resolution of magnetoencephalography to investigate the dynamics of cortical processing of changes in interaural correlation, a measure of interaural similarity, and compare them with behavior. Stimuli are interaurally correlated or uncorrelated wideband noise, immediately followed by the same noise with intermediate degrees of interaural correlation. Behaviorally, listeners' sensitivity to changes in interaural correlation is asymmetrical. Listeners are faster and better at detecting transitions from correlated noise than transitions from uncorrelated noise. The cortical response to the change in correlation is characterized by an activation sequence starting from ∼50 ms after change. The strength of this response parallels behavioral performance: auditory cortical mechanisms are much less sensitive to transitions from uncorrelated noise than from correlated noise. In each case, sensitivity increases with interaural correlation difference. Brain responses to transitions from uncorrelated noise lag those from correlated noise by ∼80 ms, which may be the neural correlate of the observed behavioral response time differences. Importantly, we demonstrate differences in location and time course of neural processing: transitions from correlated noise are processed by a distinct neural population, and with greater speed, than transitions from uncorrelated noise.

Original languageEnglish (US)
Pages (from-to)8518-8527
Number of pages10
JournalJournal of Neuroscience
Volume25
Issue number37
DOIs
StatePublished - Sep 14 2005

Keywords

  • Auditory cortex
  • Auditory-evoked response
  • Binaural sluggishness
  • Binaural system
  • Change detection
  • Magnetoencephalography
  • Psychophysics

ASJC Scopus subject areas

  • Neuroscience(all)

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