MAPT and Alzheimer disease: Indeed, the Braak hypothesis, originally formulated to explain the progressive infiltration of adjacent brain areas with Levy bodies in Parkinson's disease, has been recently applied to explain also the progression of hyperphosphorylated tau within dystrophic neurons in Alzheimer's disease, and the centripetal progression of PrPSc from the periphery to the brain in infectious TSEs (Braak and Braak, 1995; Braak et al., 2004; Iwasaki, 2020).