MAPT and Alzheimer disease: Furthermore, when split according to neuropathological diagnosis, and controlled for age, a significant correlation was observed between AT-8 phospho-tau and Braak stage in the non-AD control group (Braak 0-IV) in GM (Fig. 1c.i, r = 0.47, p < 0.01) and WM (Fig. 1c.i, r = 0.43, p < 0.05), but not in AD cases (Braak V-VI, Fig. 1c.i, p > 0.05).