Right-hemisphere auditory cortex is dominant for coding syllable patterns in speech

Daniel A. Abrams, Trent Nicol, Steven Zecker, Nina Kraus

Research output: Contribution to journalArticlepeer-review

174 Scopus citations

Abstract

Cortical analysis of speech has long been considered the domain of left-hemisphere auditory areas. A recent hypothesis poses that cortical processing of acoustic signals, including speech, is mediated bilaterally based on the component rates inherent to the speech signal. In support of this hypothesis, previous studies have shown that slow temporal features (3-5 Hz) in nonspeech acoustic signals lateralize to right-hemisphere auditory areas, whereas rapid temporal features (20-50 Hz) lateralize to the left hemisphere. These results were obtained using nonspeech stimuli, and it is not known whether right-hemisphere auditory cortex is dominant for coding the slow temporal features in speech known as the speech envelope. Here we show strong right-hemisphere dominance for coding the speech envelope, which represents syllable patterns and is critical for normal speech perception. Right-hemisphere auditory cortex was 100% more accurate in following contours of the speech envelope and had a 33% larger response magnitude while following the envelope compared with the left hemisphere. Asymmetries were evident regardless of the ear of stimulation despite dominance of contralateral connections in ascending auditory pathways. Results provide evidence that the right hemisphere plays a specific and important role in speech processing and support the hypothesis that acoustic processing of speech involves the decomposition of the signal into constituent temporal features by rate-specialized neurons in right-and left-hemisphere auditory cortex.

Original languageEnglish (US)
Pages (from-to)3958-3965
Number of pages8
JournalJournal of Neuroscience
Volume28
Issue number15
DOIs
StatePublished - Apr 9 2008

Keywords

  • Auditory cortex
  • Cerebral asymmetry
  • Children
  • Speech
  • Speech envelope
  • Syllable

ASJC Scopus subject areas

  • Neuroscience(all)

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