MAPT and Alzheimer disease: Studies of Alzheimer's disease (AD) are mainly focused on the entorhinal cortex, hippocampus, and neocortex because of the massive accumulation with disease progression of β-amyloid deposits (diffuse and senile plaques) and hyper-phosphorylated tau-containing neurofibrillary tangles (NFTs), neuropil threads, and dystrophic neurites in these regions.