We recognize the cellular substrate and mechanism driving increased TSPO radioligand binding might be disease-specific, with reports suggesting varying effects on TSPO expression across different diseases, species and models.20,22,24-27 Further work is required to exclude the possibility that the association between microglia and TSPO radioligand binding is PSP/tauopathy-specific, with PET-to-pathology comparisons needed in other neurodegenerative disorders. Here, TSPO is linked to supranuclear palsy, progressive, 1.