(C Immunostaining assay of SOX1 (red) after 4 HDAC inhibitors (4i), including RG2833 (2833, 2μM), CAY10683 (CAY, 2μM), PCI-34051 (34051, 5μM) and Bufexamac (Buf, 12.5μM), treatment or remove one inhibitor from these 4 HDAC inhibitors (4i) in V1-PAKI cells on day 16 of dorsal neural differentiation Scale bar, 100 μm. 