Is our self based on reward? Self-relatedness recruits neural activity in the reward system.

Every organism has to evaluate incoming stimuli according to their current and future significance. The immediate value of stimuli is coded by the reward system, but the processing of their long-term relevance implements a valuation system that implicates self-relatedness. The neuronal relationship between reward and self-relatedness remains unclear though. Using event-related functional MRI, we investigated whether self-relatedness induces neural activity in the reward system. Self-relatedness induced signal changes in the same regions that were recruited during reward including the bilateral nucleus accumbens (NACC), ventral tegmental area (VTA) and ventromedial prefrontal cortex (VMPFC). The fMRI signal time courses revealed no differences in early BOLD signals between reward and self-relatedness. In contrast, both conditions differed in late BOLD signals with self-relatedness showing higher signal intensity. In sum, our findings indicate sustained recruitment of the reward system during self-relatedness. These findings may contribute to a better understanding of the reward-based nature of our self.