The EC was utilized as an AD-vulnerable brain region because it is one of the first brain regions to develop AD pathology (Braak and Braak, 1991; Bobinski et al., 1999), and it has been shown to be particularly vulnerable to APOE4-linked morphological changes (Shaw et al., 2007; Rodriguez et al., 2013; DiBattista et al., 2014). This evidence concerns the gene APOE and Alzheimer disease.