title: Action-specific value signals in reward-related regions of the human brain.
abstract: Estimating the value of potential actions is crucial for learning and adaptive behavior. We know little about how the human brain represents action-specific value outside of motor areas. This is, in part, due to a difficulty in detecting the neural correlates of value using conventional (region of interest) functional magnetic resonance imaging (fMRI) analyses, due to a potential distributed representation of value. We address this limitation by applying a recently developed multivariate decoding method to high-resolution fMRI data in subjects performing an instrumental learning task. We found evidence for action-specific value signals in circumscribed regions, specifically ventromedial prefrontal cortex, putamen, thalamus, and insula cortex. In contrast, action-independent value signals were more widely represented across a large set of brain areas. Using multivariate Bayesian model comparison, we formally tested whether value-specific responses are spatially distributed or coherent. We found strong evidence that both action-specific and action-independent value signals are represented in a distributed fashion. Our results suggest that a surprisingly large number of classical reward-related areas contain distributed representations of action-specific values, representations that are likely to mediate between reward and adaptive behavior.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, London WC1N 3BG, United Kingdom. thomas.fitzgerald@ucl.ac.uk
authors.forename: Thomas H B
authors.initials: TH
authors.lastname: FitzGerald
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Friston
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Dolan
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology; D000328:Adult; D000465:Algorithms; D001499:Bayes Theorem; D001519:Behavior / Q000502:physiology; D001921:Brain / Q000502:physiology*; D003463:Cues; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D015999:Multivariate Analysis; D017072:Neostriatum / Q000166:cytology / Q000502:physiology; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D012201:Reward; D055815:Young Adult