Human scalp potentials reflect a mixture of decision-related signals during perceptual choices

Philiastides, M. , Heekeren, H. and Sajda, P. (2014) Human scalp potentials reflect a mixture of decision-related signals during perceptual choices. Journal of Neuroscience, 34(50), pp. 16877-16889. (doi:10.1523/JNEUROSCI.3012-14.2014) (PMID:25505339) (PMCID:PMC4261107/)

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Abstract

Single-unit animal studies have consistently reported decision-related activity mirroring a process of temporal accumulation of sensory evidence to a fixed internal decision boundary. To date, our understanding of how response patterns seen in single-unit data manifest themselves at the macroscopic level of brain activity obtained from human neuroimaging data remains limited. Here, we use single-trial analysis of human electroencephalography data to show that population responses on the scalp can capture choice-predictive activity that builds up gradually over time with a rate proportional to the amount of sensory evidence, consistent with the properties of a drift-diffusion-like process as characterized by computational modeling. Interestingly, at time of choice, scalp potentials continue to appear parametrically modulated by the amount of sensory evidence rather than converging to a fixed decision boundary as predicted by our model. We show that trial-to-trial fluctuations in these response-locked signals exert independent leverage on behavior compared with the rate of evidence accumulation earlier in the trial. These results suggest that in addition to accumulator signals, population responses on the scalp reflect the influence of other decision-related signals that continue to covary with the amount of evidence at time of choice.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Philiastides, Dr Marios
Authors: Philiastides, M., Heekeren, H., and Sajda, P.
Subjects:B Philosophy. Psychology. Religion > BF Psychology
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Journal of Neuroscience
Publisher:Society for Neuroscience
ISSN:0270-6474
ISSN (Online):1529-2401
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in the Journal of Neuroscience 34(50):16877-16889
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
653861Spatiotemporal characterization of value judgments and reward processing in the human brainMarios PhiliastidesBiotechnology and Biological Sciences Research Council (BBSRC)BB/J015393/2INP - CENTRE FOR COGNITIVE NEUROIMAGING