We first applied this traditional approach and evaluated how the NAcc spontaneous activity correlates with the rest of the brain in children with ADHD-C compared to children without the disorder. Differences were prominent in the connectivity to the vmPFC. The vmPFC is commonly implicated with reward/motivational processes and was also shown to display atypical functional connectivity in ADHD in previous studies that looked at the integration of the default network in ADHD (Castellanos et al., 2008; Fair et al., 2010). The results, thus, suggest an atypical interaction between the reward circuit and the default network in ADHD. The default network is a set of brain regions proposed to be related to future planning and other self-referential processes (Buckner et al., 2008). These findings suggest an association between internal processes and NAcc functioning, consistent with the idea that altered signaling of rewards from the NAcc to the prefrontal cortex in ADHD would lead to impairment in estimating future consequences and impulsivity (Nigg and Casey, 2005).
