MAPT and Alzheimer disease: In contrast, the other two established Alzheimer’s disease biomarkers, T-tau and P-tau were preferentially detected in the ventricular compartment (T-tau: 1336 ± 1182 vs 232 ± 160 pg/l in the lumbar compartment, n = 46, P < 0.001, Fig. 3E; and P-tau: 109 ± 96 vs 25 ± 15 pg/l in the lumbar compartment, n = 46, P < 0.001, Fig. 3F).