a Sample images of immunostaining of organoids from DT1_A and DT1_U on day 30. Scale bar, 100 μm. b Quantification of the size of the SOX2+ VZ-like layer. Wnt3a-treated samples were not subjected to statistical analyses due to the limited sample size. c Sample images of immunostaining of DT1_A and DT1_U organoids showing the GABAergic population on day 30. Scale bars, 500 μm. d Quantification of the fluorescence intensity of the GABAergic population. Two-way ANOVA with post hoc t-test: ****p < 0.0001; **p < 0.01; *p < 0.05; n.s. not significant (b, d). See also Figs. S5 and S6.