Neural dynamics of phoneme sequences: Position-invariant code for content and order

Speech consists of a continuously-varying acoustic signal. Yet human listeners experience it as a sequence of discrete units (phonemes and words). To identify how the brain continuously represents and updates speech units, we recorded two-hour magnetoencephalograms from 21 subjects listening to shor...

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Bibliographic Details
Published inbioRxiv
Main Authors Gwilliams, Laura, King, Jean-Remi, Marantz, Alec, Poeppel, David
Format Paper
LanguageEnglish
Published Cold Spring Harbor Laboratory 02.11.2021
Edition1.2
Subjects
Online AccessGet full text
ISSN2692-8205
DOI10.1101/2020.04.04.025684

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Summary:Speech consists of a continuously-varying acoustic signal. Yet human listeners experience it as a sequence of discrete units (phonemes and words). To identify how the brain continuously represents and updates speech units, we recorded two-hour magnetoencephalograms from 21 subjects listening to short narratives. Our encoding and decoding analyses show that the human brain uses a dynamic coding scheme to represent approximately three successive phonetic features at each time sample. These dynamic phonetic representations, not directly accessible from the acoustic signal, are active earlier when phonemes are more predictable, and are sustained when lexical identity is uncertain. The results reveal how phoneme sequences in natural speech are neurally represented and shed new light on how the human brain combines them to probe the mental lexicon. The human brain keeps track of the relative order of speech sound sequences by jointly encoding content and elapsed processing time
Bibliography:Competing Interest Statement: The authors have declared no competing interest.
ISSN:2692-8205
DOI:10.1101/2020.04.04.025684