MAPT and Alzheimer disease: In vivo studies in DLB and AD animal models have indicated a synergistic relationship between α-synuclein and tau (Masliah et al., 2001; Frasier et al., 2005; Höglinger et al., 2005; Duka et al., 2009; Clinton et al., 2010; Khandelwal et al., 2010; Emmer et al., 2011; Haggerty et al., 2011; Morris et al., 2011; Wills et al., 2011; Masuda-Suzukake et al., 2014).