APOE and Alzheimer disease: Previous single modality studies have frequently reported SVAN hub connectivity enhancement in the presymptomatic stage (i.e., healthy apolipoprotein-E (APOE) e4 carriers) (Han and Bondi, 2008; Machulda et al., 2011), the amnestic MCI stage (Bai et al., 2012a) and the clinical AD stage (Zhou et al., 2010; Zhou and Seeley, 2014), which represents the disruption of the balance between SVAN and other networks.