The cortical feeder cultures were prepared by dissociating dorsal cortices from 250μm coronal slices of E13.5 mouse brain, and cultured as described previously (Xu et al., 2010). For human cortical feeder preparation, cells were subjected to XLSB-mediated neural induction in the presence of cylcopamine and purified for CD24+/CD44−/CD184+ at day 32 (see Supplemental Experimental Procedures for details).
