MAPT and Alzheimer disease: Fortunately, in an elegant study, using PET imaging for microglial activation [(11C) PBR28], β-amyloid (Aβ) [(18F) AZD4694], and tau [(18F) MK-6240], Pascoal et al. (2021) in vivo demonstrated the relationships of these three key pathological features in 130 individuals across the spectrum of aging and AD.