MAPT and supranuclear palsy, progressive, 1: In agreement with the autopsy study mentioned in the Introduction, which showed a relationship between a higher degree of tau deposits in the left superior frontal cortex and worse fluency (Schofield et al., 2012), our correlation analysis between Letter fluency and brain metabolism in 31 patients with PSP identified a very definite locus of dysfunction centered around left BA6, and including both the SMA and the lateral superior frontal cortex.