To further illustrate the effect of CSF GAP-43 on tau accumulation rates across the Q1-Q4 ROIs, we compared ROI-specific tau-PET change rates stratified by high vs. low CSF GAP-43 defined by median split in the subsample of 54 Aβ+ subjects that are on the AD trajectory (Fig. 4A). Here, MAPT is linked to Alzheimer disease.