E14Tg2a (E14) mouse ESCs were cultured on gelatin-coated plates using Knock-out DMEM (Life Technologies, 10829018) supplemented with 15% FBS (Life Technologies, 10082147) and LIF. For the AntNPC differentiation86 (link), ESCs were plated at 12,000 cells/cm2 on gelatin-coated plates and grown for three days in N2B27 medium supplemented with 10 ng/ml bFGF (Life Technologies, PHG0368) without serum or LIF. Subsequently, cells were grown for another two days in N2B27 medium without bFGF (D3–D5). From D2-D5 the N2B27 medium was supplemented with 5 mM Xav93987 (link) (Sigma, 284028-89-3). N2B27 medium: Advanced Dulbecco’s Modified Eagle Medium F12 (Life Technologies, 21041025) and Neurobasal medium (Life Technologies, 12348017) (1:1), supplemented with 1× N2 (Life Technologies, 17502048), 1× B27 (Life Technologies, 12587010), 2 mM L-glutamine (Life Technologies, 25030024), 40 mg/ml BSA (Life Technologies, 15260037), 0.1 mM 2-mercaptoethanol (Life Technologies, 31350010).