Neural correlates of reward processing: impact of individual differences in preference for prosocial interactions

Introduction: There is an ongoing debate about the neural mechanisms and subjective preferences involved in the processing of social rewards compared to non-social reward types. 

Methods: Using whole-brain functional magnetic resonance imaging (fMRI), we examined brain activation patterns during the anticipation and consumption phases of monetary and social rewards (using the Monetary and Social Incentive Delay Task—MSIDT, featuring human avatars) and their associations with self-reported social reward preferences measured by the Social Reward Questionnaire (SRQ) in 20 healthy right-handed individuals. 

Results: In the anticipation phase, all reward types activated the dorsal striatum, middle cingulo-insular (salience) network, inferior frontal gyrus (IFG), and supplementary motor areas. The consumption phase primarily engaged posterior cortical areas. Higher preference for prosocial interactions (as assessed by SRQ) was associated with increased right posterior cingulate activity during monetary reward anticipation and enhanced activity in the left striatum and salience network activation during social reward anticipation. In the consumption phase, higher prosociality was associated with stronger activation in frontal regions, the dorsal striatum, and the thalamus for monetary rewards and stronger putamen activity for social rewards. 

Conclusions: Individual differences in social reward preferences, particularly prosocial tendencies, are associated with distinct neural activations during reward processing. These findings have potential implications for understanding altered reward processing in clinical populations.