Sex-dependent differences in human reward processing : A systematic review

Abstract: Much work has been done in the neuroscience of reward processing, such as; mapping brain areas, key neurotransmitters, and connectivity patterns related to different aspects of reward-related behavior. There are a lot of suggested behavioral and neural sex differences in reward processing, primarily based on animal studies of reward behavior. This review aimed to systematically review publications on human neurofunctional sex differences in reward processing, and provide a more stable footing for future research in the field. Two searches through Web of Science and Scopus for publications that combined neuroimaging with behavioral tasks for examining functional sex differences in neural reward processing. The searches produced nine studies (n=9) that were included after the screening process. There are significant differences between males and females in reward processing, specifically in the striatum, orbitofrontal cortex, prefrontal cortex, nucleus accumbens, and insula. However, the full extent of these differences, and the underlying causes, are still not clear. There is a lack of control for important confounding factors in the present field of sex differences in reward processing. Future research in this field has to consider all of the underlying factors that cause men and women to differ, such as the impact of gonadal hormone fluctuations and societal pressures. If these factors were taken into account, data of higher validity and generalizability could have been produced.