How Punishment Sensitivity affects Delay Discounting: The Mediating Role of Functional Connectivity between the Left Dorsal Medial Prefrontal Cortex and Right Postcentral Gyrus.

Punishment sensitivity refers to an individual's tendency to perceive and respond to punishment and other negative outcomes. Delay discounting refers to that an individual tends to devalue the subjective worth of future rewards as the waiting time increases. Previous findings suggest that punishment sensitivity may be related to delay discounting, but direct evidence for this association and the neural mechanisms underlying this relationship remain unclear. To address this question, we combined behavioral measurements, voxel-based morphometry (VBM), resting-state fMRI, and mediation analysis to investigate their brain-behavior mechanisms. Behaviorally, punishment sensitivity negatively correlated with delay discounting. Furthermore, VBM analysis found that the gray matter volume (GMV) of the left dorsal medial prefrontal cortex (dmPFC_L) is positively associated with punishment sensitivity, and neuroimaging results revealed that the functional connectivity between the dmPFC_L and the right postcentral gyrus (PCG_R) was positively associated with punishment sensitivity. More critically, mediation analysis showed that this functional connectivity exhibited a partial mediation with a statistical suppressor effect in the association with delay discounting. These results suggest that the functional connectivity between the dmPFC_L and PCG_R may represent a neural correlate of this association, providing new insights and a neurobiological interpretation for this association.