title: Dissociable contributions of ventromedial prefrontal and posterior parietal cortex to value-guided choice.
abstract: Two long-standing traditions have highlighted cortical decision mechanisms in the parietal and prefrontal cortices of primates, but it has not been clear how these processes differ, or when each cortical region may influence behaviour. Recent data from ventromedial prefrontal cortex (vmPFC) and posterior parietal cortex (PPC) have suggested one possible axis on which the two decision processes might be delineated. Fast decisions may be resolved primarily by parietal mechanisms, whereas decisions made without time pressure may rely on prefrontal mechanisms. Here, we report direct evidence for such dissociation. During decisions under time pressure, a value comparison process was evident in PPC, but not in vmPFC. Value-related activity was still found in vmPFC under time pressure. However, vmPFC represented overall input value rather than compared output value. In contrast, when decisions were made without time pressure, vmPFC transitioned to encode a value comparison while value-related parameters were entirely absent from PPC. Furthermore, under time pressure, decision performance was primarily governed by PPC, while it was dominated by vmPFC at longer decision times. These data demonstrate that parallel cortical mechanisms may resolve the same choices in differing circumstances, and offer an explanation of the diverse neural signals reported in vmPFC and PPC during value-guided choice.
authors.affiliation: FMRIB Centre, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; Center for Behavioral Brain Sciences, Otto-von-Guericke-Universität Magdeburg, Germany. Electronic address: jocham@ovgu.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Jocham
authors.affiliation: The Robotics Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
authors.forename: P Michael
authors.initials: PM
authors.lastname: Furlong
authors.affiliation: Department of Systems Neuroscience, University of Hamburg, UKE, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Inga L
authors.initials: IL
authors.lastname: Kröger
authors.affiliation: Graduate Programme in Neuroscience, University of Oxford, United Kingdom.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Kahn
authors.affiliation: FMRIB Centre, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, United Kingdom.
authors.forename: Laurence T
authors.initials: LT
authors.lastname: Hunt
authors.affiliation: FMRIB Centre, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; Wellcome Trust Centre for Neuroimaging, University College London, 12 Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Tim E J
authors.initials: TE
authors.lastname: Behrens
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002755:Choice Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D012201:Reward; D055815:Young Adult
keywords: Decision making; Parietal cortex; Reward; Ventromedial prefrontal cortex; fMRI