While there appears to be an association between risk-taking behavior and ventral striatal activation, in the Galvan study 16 no correlation was reported between ventral striatal activity with impulsivity. Rather, impulsivity ratings were correlated with age, consistent with numerous imaging studies showing linear development with age in prefrontal cortical recruitment during impulse control tasks 7, 75, 77 (and see reviews by 34, 86). Moreover, recent studies have shown that impulsivity ratings inversely correlate with volume of the ventral medial prefrontal cortex in a sample of healthy boys (7–17yrs) 87. Finally, studies of clinical populations characterized by impulsivity problems like ADHD, show impaired impulse control and reduced activity in prefrontal regions compared to controls, 88, 89 but do not show heightened responses to incentives 90.
