MAPT and Alzheimer disease: In these monkeys, AD-like characteristics can be generated within a few months following a single stereotaxic injection of AAVs, yet the monkeys exhibit many defining pathological features of AD, such as the accumulation of 3-repeat (3R)/4-repeat (4R) tau isoforms, the hyperphosphorylation of exogenous and endogenous tau, neuronal loss, inflammatory responses, medial temporal lobe atrophy, elevated Aβ burden, neurofibrillary tangle (NFT) formation, vascular abnormalities, and multidomain cognitive dysfunctions.