Society for Neuroscience, Journal of Neuroscience, 46(32), p. 16417-16423, 2012
DOI: 10.1523/jneurosci.3254-12.2012
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Estimating the value of potential actions is crucial for learning and adaptive behaviour. 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 (vmPFC), putamen, thalamus and insula cortex. By 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 find 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 behaviour.