GFAP and infection: In contrast, in NeuroD1 group, Cre signal was only detected at early time of infection at 2 weeks in GFAP-positive astrocytes but not at 2–6 months after viral infection (Supplementary Figures S8A’–C’, right side), confirming that astrocytes have been converted into neurons and the GFAP promoter activity of GFAP::Cre has been downregulated after neuronal conversion.