APOE and Atrophy: Many studies have shown that APOE-ε4 promotes Aβ deposition in the brain (including neocortical areas) and disrupts the cortico-hippocampal network, which indirectly causes hippocampal atrophy through cortical denervation, further affecting the rate of hippocampal volume loss and gray matter atrophy (Geroldi et al., 2000; Schuff et al., 2009; Hesse et al., 2019; Yan et al., 2020).