MAPT and Mental deterioration: Because our recent data showed major differences in seeding potency in vitro and propagation of distinct conformers of insoluble four-repeat AD tau aggregates in cells [3,27], we hypothesized that the structural organization of the microtubule-binding domain (MTBD) of misfolded tau could generate different conformers of misfolded tau (strains), which in turn could affect the rates of cognitive decline.