MAPT and Atrophy: In this regard, our previous finding that tau PET was longitudinally associated with atrophy rates in cortical regions that are proximal to the tau-related white matter tracts herein (i.e, hippocampus and temporoparietal cortices) raised the intriguing possibility that the spread of tau pathology from the affected white matter tracts to the adjacent gray matter regions may lead to cell death and subsequent atrophy as seen on MRI36.