The VBM result demonstrated structural impairment in all three networks. However, structural damage was mainly present in the frontal lobe, including the mPFC, SMA, orbitofrontal cortex, and left superior/middle/inferior frontal cortex involved in the anterior SN and right ECN. Reductions in hippocampal volume including bilateral hippocampus and parahippocampal gyrus were reported in the AUD group, even though none of the participants had a history of alcoholic Korsakoff syndrome. Gray matter density in the right posterior insula, thalamus, and ACC had also decreased. These results support the diffuse brain hypothesis suggesting diffuse damage in the cerebral cortex caused by the neurotoxic effects of alcohol (7, 10). The frontal lobe and hippocampus are rich in glucocorticoid receptors and considered particularly susceptible to the neuro-toxic effect of alcohol (56, 57), supporting the vulnerability of these regions (58, 59).
