Fig. 5: Progenitor cells in the CGE and EC stream region continue dividing at birth.

a, Coronal map (at birth) of Ki-67⁺ cells (green), blood vessels (red) and DCX⁺ cell clusters (cyan) along the tLV and extending along the EC stream. Boxes show the anatomical locations of subsequent panels. b, Ki-67⁺vimentin⁺ RG (arrow) at the medial end of the EC stream region at birth. c, At birth, Ki-67⁺vimentin⁺ cell bodies located proximal to the tLV are either HOPX⁺ (arrowhead) or HOPX^– (arrow). d, Lineage trajectory analysis using Monocle reveals a bifurcation emerging from the cluster of RG into an oligodendrocyte lineage (blue, top) and a neurogenic lineage of excitatory cells (green, bottom); on the right, expression of key maturation-associated genes across pseudotime. e, Ki-67⁺COUPTFII⁺ cells (arrows) and DCX⁺COUPTFII⁺ cells (arrowheads) located in the CGE region of the temporal lobe at birth. f, TEM within the CGE region at birth (near boxed inset in e) showing a pair of recently divided cells completing cytokinesis (top boxed region; left of the two magnified panels) near a cell with ultrastructural features of a migratory neuron (bottom boxed region; right of the two magnified panels). g,h, Quantification of the density of Ki-67⁺ cells in the CGE (g) from 22 GW to birth and in the EC stream (h) from 28 GW to 11 postnatal months. Data points are the average section density at each age; bars are mean ± s.e.m., n = 4 individuals (g) and n = 6 individuals (h) in three independent experiments. Scale bars: 1 mm (a); 100 µm (b, c top, e left); 10 µm (c bottom, e right, f left); 2 µm (f right).