MAPT and supranuclear palsy, progressive, 1: This is supported by our in vitro binding assay data, showing a stronger affinity of PI-2620 to 4 R tau fibrils than Flortaucipir (Fig. 2A), as well as the postmortem autoradiography assessments in PSP patients, showing that stronger PI-2620 signal is observed in brain regions with higher AT8-stained tau pathology (Fig. 2C, D).