The role of dopaminergic nuclei in predicting and experiencing gains and losses: A 7T human fMRI study

The ability to predict the outcomes of actions based on experience is crucial for making successful decisions in new or dynamic environments. In animal studies using electrophysiology, it was found that dopamine neurons, located in the substantia nigra (SN) and the ventral tegmental area (VTA), have a crucial role in feedback-based learning. However, human neuroimaging studies have provided inconclusive results. The present work used ultrahigh field (7 Tesla) structural and functional MRI and optimized protocols to extract SN and VTA signals in human participants. In a number-guessing task, we found significant correlations with reward prediction error and risk in both the SN and the VTA and no correlation with expected value. We also found a surprise signal in the SN. These results are in line with a recent framework that proposed a differential role for the VTA and the SN in, respectively, learning of values and surprise.