Neural activity associated with binaural processes for the perceptual segregation of pitch

Blake W. Johnson*, Michael Hautus, Wes C. Clapp

*Corresponding author for this work

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Objective: We measured late cortical potentials in a psychophysical procedure for binaural unmasking of a dichotically-embedded pitch. Methods: Late-latency auditory evoked potentials were measured from 128 recording channels in 13 healthy subjects. Control stimuli consisted of 500 ms segments of broadband acoustic noise presented identically to both ears via earphones, evoking a perception of noise localized in the centre of the head. Dichotic pitch stimuli were created by introducing a dichotic delay to a narrow frequency region of the same noise segments, and resulted in a perception of both the centrally-located noise and a right-lateralized pitch. Results: Both stimuli evoked late auditory event-related potentials (ERPs) characterized by a P1-N1-P2 complex of waves between 60 and 180 ms after stimulus onset. ERPs associated with the control and dichotic pitch stimuli showed no amplitude differences for the P1 and N1 waves. ERPs to dichotic pitch stimuli became significantly more negative beginning at a latency around 150 ms, an effect that was maximal between 210 and 280 ms. Topographic mapping showed that this late negativity was lateralized to the left hemisphere. Conclusions: The late negative wave elicited by the dichotic pitch stimulus reflects neural processing that is dependent upon binaural fusion within the auditory system. Significance: The dichotic pitch paradigm may provide a useful tool for the electrophysiological assessment and study of the temporal processing capabilities of the auditory system. This paradigm may also be useful for the study of binaural mechanisms for the perceptual segregation of concurrent sound sources.

Original languageEnglish
Pages (from-to)2245-2250
Number of pages6
JournalClinical Neurophysiology
Volume114
Issue number12
DOIs
Publication statusPublished - Dec 2003
Externally publishedYes

Keywords

  • Auditory evoked potential
  • Auditory perception
  • Brain mapping
  • Dichotic pitch
  • Interaural time difference
  • Sound localization

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