Our findings, in general, are in accordance with previous studies that showed the involvement of NAcc in ADHD and the association of impairments in this region with reward processes and impulsivity. Functional MRI studies have determined that some of the main brain regions recruited while subjects experienced appropriate rewarding stimuli (e.g., money or positive feedback) include the ventral striatum (i.e., NAcc), orbitofrontal cortex (OFC) and other areas of PFC (McClure et al., 2004b). In our sample we found that spontaneous correlated activity between NAcc and left aPFC, and NAcc and vmPFC are correlated with indices of delay discounting, that is, the strength of correlation between these regions is associated with greater impulsivity as measured by the delay discounting task.
