Representative hESC (H9) cerebral organoids at (a) 8 and (b) 18 days of development(a1, b1) tile scanning of DAPI; yellow arrows point to cortical rosettes, enlarged in a2 and b2; at day 18, zones are outlined—ventricular zone (VZ), intermediate zone (IZ), and cortical zone (CZ). Immunostaining: (A4, B5) Ki67+ proliferating cells; (a3, b3, b4), doublecortin (DCX+) neuroblasts, βIII-tubulin+ immature neurons
