Although we observed several AT8+ neurons within the piriform cortex of PSP-inoculated rats, we did not detect a significant increase of tau prions measured in the HEK(tau-RD)-YFP cell model with any of the three PSP or three AD human brain samples we inoculated, when compared with the cognitively unimpaired control human brain sample. The gene discussed is MAPT; the disease is Alzheimer disease.