MAPT and Alzheimer disease: The search for neurodegenerative-susceptible brain areas dates back several decades, and the spread of pathological tau in a “prion-like” fashion from one neuron to the next has been hypothesized to correlate with AD (DeVos et al., 2018) and form the basis of Braak staging of AD-related changes (Braak and Braak, 1991) that can be investigated by tau-PET imaging (Biel et al., 2021).