MAPT and Alzheimer disease: The hippocampus is a core region in the study and understanding of brain diseases, in particular, in Alzheimer’s disease (AD)-related pathology.1 Previous studies have evidenced that the accumulation of tau (and to a lesser extend amyloid beta [Aβ]) pathologies in the hippocampus is associated with metabolic and structural changes of the hippocampus itself, but also of other brain regions in healthy aging and dementia populations,2,3 hence suggesting a role of hippocampal networks in AD pathology.