MAPT and supranuclear palsy, progressive, 1: Post hoc univariate F-tests revealed significantly lower γ-aminobutyric acid type A-associated benzodiazepine (BZ) binding site (p = 0.002) and 5-HT2 (p = 0.004) receptor densities in the caudate nucleus of PSP brains with moderate to severe tau pathology than in PSP brains with mild tau pathology.