Mapping frontostriatal white matter tracts and their association with reward-related ventral striatum activation in adolescence

•Adolescence is a critical period for reward processing development.•In adolescents, VS white matter connectivity is variable across the PFC.•VS–PFC white matter connectivity was related to VS functional activation to reward.•However, the relation between structure and activation varied by reward type.•The adolescent brain processes social and monetary rewards differently. The ventral striatum (VS) is implicated in reward processing and motivation. Human and non-human primate studies demonstrate that the VS and prefrontal cortex (PFC), which comprise the frontostriatal circuit, interact to influence motivated behavior. However, there is a lack of research that precisely maps and quantifies VS–PFC white matter tracts. Moreover, no studies have linked frontostriatal white matter to VS activation. Using a multimodal neuroimaging approach with diffusion MRI (dMRI) and functional MRI (fMRI), the present study had two objectives: 1) to chart white matter tracts between the VS and specific PFC structures and 2) assess the association between the degree of VS–PFC white matter tract connectivity and VS activation in 187 adolescents. White matter connectivity was assessed with probabilistic tractography and functional activation was examined with two fMRI tasks (one task with social reward and another task using monetary reward). We found widespread but variable white matter connectivity between the VS and areas of the PFC, with the anterior insula and subgenual cingulate cortex demonstrating the greatest degree of connectivity with the VS. VS–PFC structural connectivity was related to functional activation in the VS though activation depended on the specific PFC region and reward task.