Few neuroimaging studies include sufficient numbers of women to power an analysis by SG. Those that have examined SG differences in brain function and structure related to alcohol risk, alcohol use, or AUD generally demonstrate mixed findings. PET neuroimaging of drinking implicates SG-dependent differences in striatal DA release and in opioid receptor availability; social-drinking men have greater alcohol-evoked DA release compared to women and in AUD, men demonstrate regional differences in KOR availability compared to women. MRI and fMRI studies are largely mixed, suggesting either reduced gray matter volume or region-specific activation in AUD men only, in AUD women only, or no SG differences in cortical or subcortical brain volumes or activity. One MRS study found no SG differences in brain metabolites of heavy drinking men and women. Nonetheless, common brain regions implicated in these SG-dependent findings are in cortico-limbic areas. Cortico-limbic pathways should be considered in future work examining SG differences in the neuroimaging of AUD. The degree of mixed results on SG-based differences in brain function and morphometry in AUD may be a result of the low rates
