When Music Loses Its Pleasure: Hippocampal Cingulum White Matter as a Structural Mediator of Musical Reward Decline in Aging

Individuals ability to obtain pleasure from music, referred to as musical reward sensitivity, declines with age, yet the neural mechanisms underlying this decline remain unclear. In this study, we investigated musical reward sensitivity measured in 58 older adults and 131 young adults. Consistent with prior findings, young adults reported higher musical reward sensitivity than older adults (p < 0.05). To identify neuroanatomical predictors of musical reward sensitivity, we employed the elastic-net model to predict musical reward sensitivity using white matter microstructural properties and gray matter morphometric properties from the whole brain. In older adults, fractional anisotropy (FA) in the bilateral hippocampal cingulum (CGH) and external capsule (EC) reliably predicted individual differences in musical reward sensitivity. Moreover, FA in the right CGH significantly mediated the relationship between age and musical reward sensitivity in older adults. Notably, these associations were specific to musical reward sensitivity in older adults--that is, they did not replicate in young adults, and did not extend to general reward sensitivity. Together, these findings highlight the critical role of white matter integrity, particularly within the hippocampal-limbic pathways, in age-related changes in musical reward processing, and suggest a potential neurobiological target for interventions aimed at enhancing well-being in older adulthood. Key pointsO_LIWhole-brain machine learning identified the FA in the hippocampal cingulum and external capsule as robust predictors of musical reward sensitivity in older adults. C_LIO_LIFA in the right hippocampal cingulum mediated the association between age and musical reward sensitivity. C_LIO_LIThese findings extend previous association-based studies by identifying hippocampal-limbic white matter as a key neural substrate supporting musical reward sensitivity decline during aging. C_LI