Alcohol-consumption related white matter (WM) microstructural alterations are a hallmark change associated with AUD18–20. Neuroimaging studies have consistently shown WM degeneration of the corpus callosum in AUD3,21,22. However, the effects of AUD on WM microstructure, as evidenced by decreased fractional anisotropy (FA) and increased mean diffusivity (MD), are not limited to the corpus callosum but are also seen in the internal and external capsules, fornix, frontal forceps, superior cingulate, and longitudinal fasciculi3,21,23. Further, research indicates that anterior and superior WM systems are more likely to show changes associated with AUD than posterior and inferior systems24. However, because conventional diffusion tensor imaging (DTI) measures (FA and MD) are based on a simplistic brain tissue microstructure model, they fail to account for the complexities of neurite geometry25. For example, the lower FA observed in individuals with AUD may reflect lower neurite density and/or greater orientation dispersion of neurites, which conventional DTI measures do not differentiate26,27.
