iPSCs were dissociated to single cells and quickly reaggregated in U-bottomed 96-well plates (Greiner Bio-One) pre-coated with 2% Pluronic F-127 (Sigma-Aldrich) for embryoid body (EB) formation. EBs were cultured in DMEM/Ham's F12 (Life Technologies) supplemented with 5% knockout serum replacement, 2 mM L-glutamine, 1% NEAA, 0.1 μM 2-mercaptoethanol (Life Technologies), 2 μM dorsomorphin, and 10 μM SB431542 (Wako) at stage 1 of the neural induction (days 0–8). EBs were transferred onto Matrigel (1:60 dilution)-coated 6-well plates and cultured in DMEM/Ham's F12 supplemented with N2 supplement (Life Technologies) and 2 μM dorsomorphin (Wako) at stage 2 (days 8–24). At 24 days after differentiation, neural precursor cells were cultured in Neurobasal Medium (Life Technologies) supplemented with B27 without vitamin A, Glutamax, 10 ng/mL brain-derived neurotrophic factor, 10 ng/mL GDNF, and 10 ng/mL NT3 on Matrigel-coated 10 cm dishes and refreshed every 3 days at stage 3 (days 24–60). Cells at 60 days after differentiation were transferred onto Matrigel (1:60 dilution)-coated 10-cm dishes and cultured in DMEM/Ham's F12 supplemented with N2 supplement (Life Technologies) and refreshed every 3 days at stage 4 (days
