MAPT and Alzheimer disease: The neurofibrillary tangles formed by phosphorylated Tau are another important pathological marker of AD, but phosphorylated Tau is not all toxic, only the phosphorylation of specific residues AT180 (Tr231 and SR235) or 12E8 (Ser262 and Ser356) is pathologic, and phosphorylated Tau can reduce hippocampal excitability (Hatch et al., 2017).