Evidence for causal top-down frontal contributions to predictive processes in speech perception
Nature Publishing Group
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Cope, T., Sohoglu, E., Sedley, W., Patterson, K., Jones, S., Wiggins, J., Dawson, C., et al. (2017). Evidence for causal top-down frontal contributions to predictive processes in speech perception. Nature Communications, 8 (2154)https://doi.org/10.1038/s41467-017-01958-7
Perception relies on the integration of sensory information and prior expectations. Here we show that selective neurodegeneration of human frontal speech regions results in delayed reconciliation of predictions in temporal cortex. These temporal regions were not atrophic, displayed normal evoked magnetic and electrical power, and preserved neural sensitivity to manipulations of sensory detail. Frontal neurodegeneration does not prevent the perceptual effects of contextual information; instead, prior expectations are applied inflexibly. The precision of predictions correlates with beta power, in line with theoretical models of the neural instantiation of predictive coding. Fronto-temporal interactions are enhanced while participants reconcile prior predictions with degraded sensory signals. Excessively precise predictions can explain several challenging phenomena in frontal aphasias, including agrammatism and subjective difficulties with speech perception. This work demonstrates that higher-level frontal mechanisms for cognitive and behavioural flexibility make a causal functional contribution to the hierarchical generative models underlying speech perception.
language, neurodegenerative diseases, neurophysiology
Is supplemented by: https://doi.org/10.1038/s41467-017-01958-7
This study was supported by the National Institute for Health Research, the Association of British Neurologists and Patrick Berthoud Charitable Trust (TEC fellowship); the Wellcome Trust (JBR Senior Fellowship, 103838); the Evelyn Trust; and the Medical Research Council Cognition and Brain Sciences unit (MC-A060-5PQ30, MC-A060-5PQ80).
Evelyn Trust (46722)
WELLCOME TRUST (103838/Z/14/Z)
Association of British Neurologists (ABN) (unknown)
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External DOI: https://doi.org/10.1038/s41467-017-01958-7
This record's URL: https://www.repository.cam.ac.uk/handle/1810/268202
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