39 (link),
40 (link),
41 (link) and maintained in 2i/L medium (1000 IU/mL LIF [Millipore, ESG1107], 1 μM PD0325901 [Miltenyi Biotec, 130–103‐923] and 3 μM CHIR99021 [Miltenyi Biotec, 130–103‐926] in N2B27 basal medium) on fibronectin‐coated (Millipore, FC010) plates. N2B27 basal medium contained one volume of DMEM/F12 (Gibco, 11,320–033) combined with one volume of neurobasal medium (Gibco, 21,103–049) supplemented with 0.5% N2 supplement (Gibco, 17,502–048), 1% B27 supplement (Gibco, 17,504–044), 2 mM GlutaMAX‐l (Gibco, 35,050–061), 1% MEM NEAA (Gibco, 11,140–050), 1% penicillin/streptomycin (Gibco, 15,140–122), 50 mg/L bovine serum albumin (Gibco, 15,260–037) and 110 μM β‐mercaptoethanol (Sigma, M3148).