MAPT and Alzheimer disease: Long-term potentiation (LTP) is an important plasticity mechanism at synapses in the hippocampus, which underlies the formation of new memories, and LTP is inhibited by tau with mutations that cause familial frontotemporal dementia(FTD) (8, 10, 11), as well as several AD-associated pathogenic forms of tau including hyperacetylated tau (9), hyperphosphorylated tau (12, 13), and tau oligomers (14, 15).