Personalized neural responses to self and filial reward: Functional and structural responses to motivational cues

Understanding how individuals interact with reward-related cues in their environment provides insight into the neural mechanisms underlying motivation and personalized behavior. While monetary rewards for self are well studied, the neural basis of socially relevant rewards-such as filial reward-remains less understood. This study investigated functional and structural brain responses to reward gained from a cognitive task performance for self or for parents (filial) using functional MRI (fMRI) and diffusion MRI (dMRI) in young adults, reflecting personalized interaction with environmental cues. Thirty-two healthy young adults (17 males, mean age = 23 ± 1 years) performed a 2-back working memory task cued for reward conditions for self and for parents during fMRI scanning, followed by dMRI acquisition. Participants were categorized based on the reward condition in which they showed the highest score in task performance. Self-reported reward responsiveness scores were also collected. Random-effects fMRI analysis revealed activation of the putamen in the self-reward condition, more than in the filial reward condition. Using this region as a seed, probabilistic tractography was conducted to compute connection probability indices (CPI) to key target areas: anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), dorsolateral and ventrolateral prefrontal cortices, anterior/posterior insula, and amygdala. The nucleus accumbens (NAcc) was included as a comparative seed. While the cue for self-reward elicited activation in the reward area putamen, with higher white matter connectivity from the right putamen to the ACC, a cue for filial reward significantly activated the right insula. Lateralization to the right insula was also seen in the structural connectivity to NAcc in the filial group. Filial reward also displayed a positive relationship between white matter connectivity of left NAcc to PCC with reward responsiveness. These results demonstrate individualized neural responses shaped by the self and social relevance of the reward.