MAPT and Alzheimer disease: According to this model, the earliest AD markers are those related to amyloid deposits in Positron emission tomography (PET) with Pittsburg compound B (Fagan et al., 2006; Forsberg et al., 2010), followed by increased cerebrospinal fluid (CSF) tau and phospho-tau levels (Fagan et al., 2009), brain hypometabolism in FDG- PET (18-Fluorodeoxy-glucose PET), and abnormal activation pattern in functional magnetic resonance imaging (fMRI) upon cognitive task solving (Liang et al., 2011; Miao et al., 2011).