GABRB1 and alcohol dependence: Gabrb1 is coexpressed with Gabra2 in vivo.54,58GABRB1 variants have been associated with alcohol dependence and co-morbid substance use disorders54 and altered fMRI BOLD signal in multiple gyri and the caudate/insula during impulsivity and reward sensitivity tasks;63 thus, GABRB1 is hypothesized to regulate excitability of GABA-A receptors in brain regions underlying reward-related behavior and possibly addiction.