Our findings were made possible by mapping putative cis-eQTL SNPs in prefrontal cortex, a highly relevant brain region when studying addiction and other psychiatric diseases (65). The prefrontal cortex is the center for mammalian purposive action including self-control/response inhibition, emotional regulation, flexibility/control of attention, and planning and goal formation. Dysregulation of this region can increase impulsivity and risk taking, stress reactivity, and bias attention and reward- anticipation toward immediate rather than delayed gratification: all characteristics associated with greater risk of addiction (65). Differences in prefrontal cortex activity have been observed in numerous human brain imaging studies comparing healthy controls to those with heroin/opioid or other drug addictions (65).
