Our results indicate that across gender and ancestry, individuals who are vulnerable to AUD have posterior (e.g. occipital, parietal) lower gamma activity. These findings are in accordance with a recent review on the neurophysiological correlates of numerous psychiatric disorders, such as depression, bipolar disorder, anxiety and AUD, showing that the most dominant pattern of change across disorder types is power decreases across higher frequencies42. Indeed, we found lower parietal gamma (amplitude and coherence) in EA in both males and females and lower frontal-parietal gamma connectivity in only female groups in both EA and AA, all together suggesting that lower posterior gamma is not only a disease biomarker but also a predisposition factor for increased vulnerability to develop AUD. Gamma activity has been proposed to promote the feed forward or “bottom-up” flow of information from lower to higher regions of the brain during thalamocortical iterative recurrent activity43. Reduction in the gamma band power and connectivity is possibly index disruption in bottom-up communication across the posterior cortex leading to sensory and executive dysfunctions, which may reflect altered cortical integration.
