Extended Data Fig. 5: Arc is an intermediate structure in interneuron development, connecting the fetal GEs and cortical regions.

a, Schematics of the age and dissected region of the human brain used in the dataset integration to study developmental features of Arc. It includes single-cell RNA sequencing datasets of human MGE, CGE and LGE from GW 9–18 (ref. ²¹), snRNA-seq datasets of the human germinal region near the LV and cortical plate from GW 17–41 (ref. ²⁵), as well as our snRNA-seq datasets of the human Arc at GW 30–39. b, CCA integration of all cell types from human fetal GEs²¹ and term Arc, highlighting their inhibitory interneuron population similarity. c, Number of nuclei from cell types in each dataset. d, Sankey diagram derived from b shows the relationship between cells (nuclei) from the fetal GEs and the Arc. Flow thickness indicates the percentage of co-clustering between fetal GE populations and Arc populations. e, Clustering of individual cells (nuclei) from the different ages (left, top), different regions (left, bottom) and different datasets (right)^22,25 visualized by UMAP. f, The gene expression profile of well-known marker genes visualized via UMAP. g, Fate probabilities inference of immature (Imm)-interneuron clusters from the Arc, highlighting that immature CGE neurons from the Arc primarily committed to cortical fate, while immature MGE neurons committed to cortical and striatal fates, and immature LGE neurons committed to olfactory bulb (OB) interneuron fate.