Keitel, A. , Gross, J. and Kayser, C. (2018) Perceptually relevant speech tracking in auditory and motor cortex reflects distinct linguistic features. PLoS Biology, 16(3), e2004473. (doi: 10.1371/journal.pbio.2004473) (PMID:29529019) (PMCID:PMC5864086)
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Abstract
During online speech processing, our brain tracks the acoustic fluctuations in speech at different timescales. Previous research has focused on generic timescales (for example, delta or theta bands) that are assumed to map onto linguistic features such as prosody or syllables. However, given the high intersubject variability in speaking patterns, such a generic association between the timescales of brain activity and speech properties can be ambiguous. Here, we analyse speech tracking in source-localised magnetoencephalographic data by directly focusing on timescales extracted from statistical regularities in our speech material. This revealed widespread significant tracking at the timescales of phrases (0.6–1.3 Hz), words (1.8–3 Hz), syllables (2.8–4.8 Hz), and phonemes (8–12.4 Hz). Importantly, when examining its perceptual relevance, we found stronger tracking for correctly comprehended trials in the left premotor (PM) cortex at the phrasal scale as well as in left middle temporal cortex at the word scale. Control analyses using generic bands confirmed that these effects were specific to the speech regularities in our stimuli. Furthermore, we found that the phase at the phrasal timescale coupled to power at beta frequency (13–30 Hz) in motor areas. This cross-frequency coupling presumably reflects top-down temporal prediction in ongoing speech perception. Together, our results reveal specific functional and perceptually relevant roles of distinct tracking and cross-frequency processes along the auditory–motor pathway.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Keitel, Dr Anne and Kayser, Professor Christoph and Gross, Professor Joachim |
Creator Roles: | Keitel, A.Conceptualization, Formal analysis, Investigation, Methodology, Validation, Visualization, Writing – original draft, Writing – review and editing Gross, J.Funding acquisition, Supervision, Writing – review and editing Kayser, C.Conceptualization, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – review and editing |
Authors: | Keitel, A., Gross, J., and Kayser, C. |
College/School: | College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience |
Journal Name: | PLoS Biology |
Publisher: | Public Library of Science |
ISSN: | 1544-9173 |
ISSN (Online): | 1545-7885 |
Copyright Holders: | Copyright © 2018 Keitel et al. |
First Published: | First published in PLoS Biology 16(3): e2004473 |
Publisher Policy: | Reproduced under a Creative Commons License |
Data DOI: | 10.5061/dryad.1qq7050 |
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