Predictions shape confidence in right inferior frontal gyrus

It is clear that prior expectations shape perceptual decision-making, yet their contribution to the construction of subjective decision confidence remains largely unexplored. We recorded fMRI data while participants made perceptual decisions and confidence judgements, controlling for potential confounds of attention. Results show that subjective confidence increases as perceptual prior expectations increasingly support the decision, and that this relationship is associated with BOLD activity in right inferior frontal gyrus (rIFG). Specifically, rIFG is sensitive to the discrepancy between expectation and decision (mismatch), and, crucially, higher mismatch responses are associated with lower decision confidence. Connectivity analyses revealed the source of the expectancy information to be bilateral orbitofrontal cortex (OFC) and the source of sensory signals to be intracalcarine sulcus. Altogether, our results indicate that predictive information is integrated into subjective confidence in rIFG, and reveal an occipital-frontal network that constructs confidence from top-down and bottom-up signals. This interpretation was further supported by exploratory findings that the white matter density of intracalcarine sulcus and OFC negatively predicted their respective contributions to the construction of confidence. Our findings advance our understanding of the neural basis of subjective perceptual processes by revealing an occipito-frontal functional network that integrates prior beliefs into the construction of confidence.