Higher fiber‐tract myelin levels predict lower longitudinal rates of fibrillar tau independent of amyloid

Fibrillar tau progresses from initial epicenters of high tau accumulation to closely connected cortical regions during the course of Alzheimer’s disease (AD). Myelin ensheaths the interregional axonal connections, where ontogenetically late and thinly myelinated fibers are more susceptible to damage and may propel the propagation of fibrillar tau, as suggested by post‐mortem data (https://doi.org/10.1093/brain/awv236). Here we tested for the first time, in two independent samples of AD patients whether 1) regions connected to epicenters by more thickly myelinated fiber tracts show lower rates of tau‐PET accumulation, and 2) differences in regional amyloid‐PET levels explain the association between myelin and tau‐PET accumulation.