MAPT and Alzheimer disease: The findings of the non-significant differences between the AD aMCI and non-AD MCI participants in volumes of the alEC and the anterior hippocampus, the earliest sites where tau neurofibrillary tangles emerge (Braak and Braak, 1991), may indicate similar structural changes in these MTL subregions in early AD and other tau-related neurodegenerative diseases (Josephs et al., 2017).