Before discussing the findings regarding the atypical connections that are associated with impulsive decision in ADHD, it is important to highlight the findings of the correlation analysis examining reward discounting and NAcc connectivity (section 2), because this analysis is novel. Greater ln(k) (i.e. impulsive decision making) was found to be related to the connectivity between NAcc and: vmPFC, aPFC and middle temporal gyrus. Again, the association between increased NAcc-vmPFC connectivity can be linked to the idea that impairment in planning the future and estimating future consequences may lead to impulsive decision making, as the vmPFC is part of a network associated with internal processes such as past recollection and future planning – the default network (Buckner et al., 2008). The middle temporal gyrus and aPFC are regions usually associated with control functions (Dosenbach et al., 2007). As such, their relationship with a key reward region (NAcc) and association with impulsive decision making suggest that a balanced interaction between reward network and cognitive control regions may be important for impulsive control.
