NB/B27/EGF/FGF/Heparin medium (NPC induction media) was Neurobasal media (Invitrogen) supplemented with 1× B27 (without retinoic acid) (Invitrogen,12587-010) 1× penicillin/streptomycin (Invitrogen,15140-122), 2 mM L-glutamine (Invitrogen, 21051-024), 20 ng/mL EGF (Sigma-Aldrich, E9644), 20 ng/mL bFGF (R&D systems, 233-FB-001MG/CF), 5 µg/mL Heparin (Sigma, H3393). NPC maintenance media was knockout DMEM/F12 (Invitrogen, 15140-122), 2 mM GlutaMax-1 supplement (Invitrogen, 35050-061), 1× Antibiotic-antimycotic (Invitrogen, 15240-062), 2% StemPro Neural supplement (Invitrogen, A10508-01), 5 µg/mL Heparin (Sigma, H3393), 20 ng/mL bFGF (R&D systems: Cat# 233-FB-001MG/CF), 20 ng/mL EGF (Sigma-Aldrich, E9644). Plate coating buffer was 15 µg/mL Poly-ornithine (Sigma, P4957), 10 µg/mL Laminin (Sigma, L2020). To initially isolate heterogeneous populations of NPCs, iPSC colonies were grown on MEFs in hES+bFGF medium. When confluent, colonies were treated with Dispase at 1 mg/mL and passaged to Matrigel (BD Biosciences, 354277) at approximately 10–20 iPSC colonies/well of a 6-well plate and cultured in hES+bFGF media. After 3 days, bFGF was withdrawn from the media and iPSCs were allowed to differentiate. Media was changed every 2 days. After 7 days, cultures were switched to NPC induction media and changed every other day until
