MAPT and Alzheimer disease: It could also be that Aβ− individuals with accumulating tau pathology do actually have amyloid pathology, but at subthreshold or below detection levels, as it has previously been shown that in individuals who were nominally Aβ− , both the rate of Aβ accumulation and the baseline Aβ load predicted tau deposition in cortical Braak regions associated with AD [46, 47].