MAPT and Alzheimer disease: However, since extracellular amyloid β (Aβ) plaques and intracellular neurofibrillary tangles (NFTs) containing hyper-phosphorylated tau, are frequently present in the brain of patients with senile dementia, investigators eventually expanded the definition of AD to also include those with senile dementia, plaques and tangles (Figure 1) [1].