MAPT and Alzheimer disease: To this end, we combined an MRI-derived template of myelin in the brain [27] with cross-sectional PET imaging of fibrillar tau, obtained from deeply phenotyped elderly participants from two independent cohorts: the Alzheimer’s Disease Neuroimaging Initiative (ADNI) [28] and BioFINDER-1 (https://clinicaltrials.gov/ct2/show/NCT01208675).