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Proc Natl Acad Sci U S A. 2016 Apr 26;113(17):4842-7. doi: 10.1073/pnas.1524087113. Epub 2016 Apr 11.

Prestimulus influences on auditory perception from sensory representations and decision processes.

Author information

1
Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QB, United Kingdom.
2
Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QB, United Kingdom christoph.kayser@glasgow.ac.uk.

Abstract

The qualities of perception depend not only on the sensory inputs but also on the brain state before stimulus presentation. Although the collective evidence from neuroimaging studies for a relation between prestimulus state and perception is strong, the interpretation in the context of sensory computations or decision processes has remained difficult. In the auditory system, for example, previous studies have reported a wide range of effects in terms of the perceptually relevant frequency bands and state parameters (phase/power). To dissociate influences of state on earlier sensory representations and higher-level decision processes, we collected behavioral and EEG data in human participants performing two auditory discrimination tasks relying on distinct acoustic features. Using single-trial decoding, we quantified the relation between prestimulus activity, relevant sensory evidence, and choice in different task-relevant EEG components. Within auditory networks, we found that phase had no direct influence on choice, whereas power in task-specific frequency bands affected the encoding of sensory evidence. Within later-activated frontoparietal regions, theta and alpha phase had a direct influence on choice, without involving sensory evidence. These results delineate two consistent mechanisms by which prestimulus activity shapes perception. However, the timescales of the relevant neural activity depend on the specific brain regions engaged by the respective task.

KEYWORDS:

EEG; oscillatory brain activity; perception; prestimulus effects; single-trial decoding

PMID:
27071110
PMCID:
PMC4855557
DOI:
10.1073/pnas.1524087113
[Indexed for MEDLINE]
Free PMC Article

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