Interestingly, variants in 18q23 were also associated with posterior corpus callosum volume in the UK Biobank and among subjects from COGA who were also assessed with MRI. This suggests that 18q23 may contribute to variability in interhemispheric connectivity between the posterior right and left hemispheres of the brain, although the current study does not provide evidence of the direct relation of EEG coherence and corpus callosum measures (possibly due to the small MRI sample size). Chronic alcohol use is toxic to specific areas in the brain, including the corpus callosum, and impacts myelination throughout the brain81. More specifically, reductions in corpus callosum volume and microstructural degradations29 have been observed among individuals with AUD. Further, a significant loss of axonal and myelin proteins, and lower white matter integrity following chronic alcohol exposure has also been observed in the corpus callosum82,83. Diffusion tensor imaging studies of white-matter abnormalities in alcoholics highlight a disruption of myelin microstructure in prefrontal areas and the corpus callosum52 that appears distinct from callosal atrophy seen with Alzheimer’s disease29. In its most severe form, chronic alcohol abuse can
