Although cross-sectional imaging studies with different PET ligands have reported single associations of cognitive performance with in vivo tau (Brier et al., 2016; Cho et al., 2016b; Johnson et al., 2016; Ossenkoppele et al., 2016; Pontecorvo et al., 2017; Zou et al., 2020; for a review see Chandra et al., 2019) and microglial activation (Edison et al., 2008; Okello et al., 2009a; Fan et al., 2015a; Passamonti et al., 2018, 2019; Zou et al., 2020; for a review see Chandra et al., 2019), less is known about their relationship to longitudinal cognitive decline. The gene discussed is MAPT; the disease is Mental deterioration.