Deficits in inhibitory control have been observed using response inhibition tasks in PTSD patients (Falconer et al., 2008; Wu et al., 2010) and in methamphetamine dependent individuals (Monterosso et al., 2005; Tabibnia et al., 2011). Reductions in striatal D2/D3 receptor availability have been reported in the methamphetamine dependent (Volkow et al., 2001; Lee et al., 2009) including one report that observed a significant correlation with self-reported impulsivity (Lee et al., 2009). Animal studies (Nader et al., 2006; Dalley et al., 2007) have found that baseline D2-like receptor availability is predictive of impulsive behavior and cocaine self-administration. A recent report (Ghahremani et al., 2012) that examined behavioral inhibition in healthy controls found stop signal reaction time was significantly correlated (negatively) with D2/D3 availability in the caudate and putamen (i.e., those with greater receptor availability demonstrated better response inhibition). Using fMRI, they also found inhibition-related activation in frontostriatal circuits to be highly correlated (positively) with D2/D3 receptor availability. Reductions in inhibition-related frontal activation have been reported in those with PTSD (Falconer et al., 2008). Consistent with these reports, Hamidovic et al.’s (2009)
