(A and B) Immunostaining assay of SOX1 (red) in control, V1-PAKI and SOX1KO cells on day 40 of dorsal (A) and ventral (B) organoids differentiation. Scale bar, 100 μm. (C) Immunostaining assay of MAP2 (green) in control, V1-PAKI and SOX1KO cells on day 40 of dorsal organoids differentiation. Scale bar, 100 μm. (D) Immunostaining assay of GABA (green) in control, V1-PAKI and SOX1KO cells on day 40 of ventral organoids differentiation. Scale bar, 100 μm. 