Representation of action value in the brain

Abstract

Studies in rats, monkeys and humans have found action-value signals in multiple regions of the brain. These findings suggest that action-value signals encoded in these brain structures bias choices toward higher expected rewards. Recently, this view has been challenged because previously reported action-value signals could have been inflated by serial correlations in neural activity and signals related to other decision variables might be disguised as action values. I tested these possibilities using the neural data obtained from the striatum, frontal cortex, and hippocampus. We found that previously identified action-value signals in these brain areas cannot be accounted for by co-occurring serial correlations in neural activity and action value. We also found that neural activity related to action value is intermixed with signals related to other decision variables. Our findings provide conclusive evidence for broadly distributed representations of action values in the brain.