MAPT and tauopathy: PSP is neuropathologically defined as a 4R-tauopathy with 4R-tau-immunoreactive neuronal, oligodendroglial and astroglial cytoplasmic inclusions, and neuropil threads accompanied by neuronal loss and isomorphic gliosis in the basal ganglia, subthalamic nucleus, substantia nigra, brainstem, cerebellum, and cerebral cortex [6].