Sustained dorsolateral prefrontal cortex response to prosocial reward predicts lower real-world negative emotional inertia.

Rewards are essential for adaptive decision-making and well-being. While people can obtain both pro-self rewards (e.g., receiving personal bonuses) and prosocial rewards (e.g., acquiring funds for charity) in daily life, the hedonic value associated with these rewards may demonstrate habituation through repeated exposure. However, the neural mechanisms underlying reward habituation and their relationship with real-world emotional dynamics remain less understood. This study combined fMRI and the experience sampling method (ESM) to investigate neural habituation to pro-self and prosocial rewards, and the association between such habituation and real-world emotional inertia. Sixty-one participants (aged 18-25, 46 females) were scanned while performing a monetary gambling task, and their emotional states were assessed over the following 2 weeks. Analyses indicated differences in neural habituation between pro-self and prosocial rewards in the left dorsolateral prefrontal cortex (DLPFC) and right inferior temporal gyrus, although this difference should be interpreted with caution owing to the relatively weak prosocial responses. Moreover, individuals with weaker neural habituation in the left DLPFC to prosocial rewards tended to exhibit lower inertia of negative emotions in real-world contexts. These findings suggest that prosocial rewards may exhibit neural habituation patterns that differ from those of pro-self rewards and that sustained DLPFC activity in response to prosocial rewards may contribute to lower negative emotional inertia, pointing to a potential neurobehavioral pathway linking reward processing to daily emotional well-being.