The viral infection of the 3D neural spheroids was performed as previously described11,43. Briefly, hCS or hSS were transferred to a 1.5 ml microcentrifudge Eppendorf tube containing 300 μl ΝΜ with virus and incubated overnight. The next day, neural spheroids were transferred into fresh NM medium in ultralow attachment plates. Lentivirus (Lenti-Dlxi1/2b::eGFP; construct reported and applied in refs15,16 and received from J.L. Rubenstein) was generated by transfecting HEK293T cells with Lipofectamine 2000 (Thermo Fisher Scientific) and concentrating the supernatant with the Lenti-X concentrator (Clontech) 72 hrs later. Adenovirus (AAV-DJ1-hSYN::mCherry) was generated in the Stanford Gene Vector and Virus Core at Stanford.
