HTR2A and supranuclear palsy, progressive, 1: In area 24′ (Fig. 1e), patients with frontal PSP (Wilks’ lambda = 0.035, chi-square = 31.799, p = 0.033 by omnibus test) showed significantly higher NMDA, GABAB, pBZ, 5-HT2, D1, and adenosine receptor type 2A receptor densities than control subjects, whereas patients with nonfrontal PSP (Wilks’ lambda = 0.005, chi-square = 58.876, p < 0.001 by omnibus test) presented higher GABAB and pBZ densities, but lower muscarinic cholinergic receptor type 1 (M1) densities, than control subjects.