Brain Activation Features in Response to the Expectation of Receiving Rewards Through Aggression

Background: Reward expectation is an important motivation for aggression. However, despite substantial progress in behavioral studies related to reward expectation in aggression, the neural basis underlying this process remains unclear. Methods: To investigate the brain correlates of aggressive reward expectation, we developed the Harm-Gain Task (HGT). In this task, participants were informed that they could gain money by causing harm to another person and were instructed to evaluate their satisfaction with the anticipated monetary reward. Additionally, we designed a questionnaire to measure participants' moral disengagement concerning aggressive decision-making in the HGT. Thirty-four healthy Chinese university students completed the HGT while in the scanner, and their functional images were acquired using a 3.0-T Siemens Tim Trio scanner. Data from two participants were excluded from the analysis due to excessive head motion. Finally, data from 32 participants (15 males, M_age = 19.97 years, SD_age = 2.07 years) were included in the analyses. Results: Findings show that during the reward expectation phase of the HGT, (1) relative to the baseline condition, the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and middle cingulate cortex (MCC) were significantly activated. Conversely, activation in the bilateral dorsolateral prefrontal cortex (DLPFC), bilateral inferior parietal lobule (IPL), and bilateral lateral temporal cortex (LTC) was attenuated. (2) As the monetary amount raised, activation in the OFC and ACC significantly increased, while activation in the DLPFC, IPL, and LTC significantly decreased. (3) As the monetary amount raised, the heightened activation in the OFC and ACC was significantly correlated with participants' aggressive behavior and moral disengagement scores. Conclusions: The results provide preliminary evidence regarding neural correlates in aggressive reward expectation, promoting further exploration of the cognitive neural mechanisms underlying aggression.