The mechanisms by which GABRA2 may influence these behaviors are starting to emerge. The nucleus accumbens (NAcc) in the mesolimbic dopamine system is important for its integrative role of directing behavior from the limbic system and prefrontal cortex (Grace et al. 2007). The GABA system exerts its inhibitory regulation of dopaminergic function in the NAcc (Steffensen et al. 1998). Increased NAcc activation has been associated with behavioral traits such as impulsiveness (Forbes et al. 2009; Hahn et al. 2009), sensation seeking (Bjork et al. 2008), and externalizing behaviors (Yau et al. 2012). In adolescents, genetic variation in GABRA2 is associated with individual differences in NAcc activation during incentive anticipation, an aspect related to dopamine-specific motivated behaviors (Heitzeg et al. 2014).
