MAPT and Alzheimer disease: Taken together, these findings support the hypothesis that tau progresses throughout the brain along functional connections, although spatial progression may also reflect shared vulnerability of connected regions to activity-dependent stressors and proteostasis.28 Importantly, connectivity-related progression seems to be consistent across AD phenotypes, establishing functional connectivity as a universal framework for tau progression and highlighting the heightened vulnerability of highly connected brain networks to tau pathology in AD.79