Does anyone know the same-person variance in gray and white matter volume, and if it has any measurable dependence on other biological factors (hydration and/or

Does anyone know the same-person variance in gray and white matter volume, and if it has any measurable dependence on other biological factors (hydration and/or electrolyte balance come to mind as plausible)? And if any temporary[0] same-person effects are directly attributable to alcohol and its short term effects, e.g. hangover?[1] [0]I presume if permanent single-person shrinkage was observed it would have been a big enough headline to have been noticed. [1]Unless accounted for in sampling, drinkers would be statistically more likely to be experiencing transiently smaller brains from alcohol consumption or accompanying dehydration - if an effect exists.