The MGE marker NKX2-1 was expressed within rosettes and in cells rapidly migrating from them, whereas EMX2 was expressed at the base of the rosette where cells were beginning to differentiate (Supplementary Figure 4). Control neurons expressed more EMX2 and less NKX2-1 than BP neurons regardless of culture conditions; PAX6 was expressed in rosettes in both groups. Both BP and control iPSC could be patterned by exposure to the Hedgehog pathway activator purmorphamine by increasing the number of NKX2-1-positive cells (Supplementary Figures 4A and D) or to LiCl by increasing the number of neurons expressing EMX2 (Supplementary Figures 4C and F).
