Though it is known that cellular expression is not required for uptake of PrPSc aggregates [51] and in vivo neurons not expressing PrPC develop morphological abnormalities typical of prion disease with continued exposure to PrPSc over many weeks [52], in noteworthy contrast to this and our electrophysiology studies, Fang et al reported complete dependence on neuronal PrPC expression for toxicity. Here, PRNP is linked to prion disease.