Extended Data Fig. 7: Clusters of dividing progenitors and immature neurons persist along the walls of the temporal lobe at birth.

a, Maps of coronal sections of the temporal lobe lateral ventricle (tLV) indicating Ki-67⁺ cells (green dots), the V-SVZ region (grey), blood vessels (BV, red), and DCX⁺ cell clusters (cyan). Sections are spaced by 4 mm along the rostral-caudal axis beginning at the anterior/ventral uncus of the hippocampus (i), extending across the rostral dentate gyrus (DG) (v), and more caudally across the DG (ix, xiii). The three inset regions are (1) remnants of the CGE along the dorsolateral wall of the tLV, (2), the most lateral extension of the tLV, and (3) the EC stream. b, Dividing Ki-67⁺ cells expressing MCM2 are present along the lateral extension of the tLV in the temporal lobe in the V-SVZ. Sections are spaced by 1 mm. c, A stream of DCX⁺ neurons wraps around the lateral extension of the tLV (1) and is present near Ki-67⁺COUPTFII⁺ cells (arrows) (2) which are a subset of the Ki-67⁺ population in the lateral wall at birth. d, A subset of Ki-67⁺ cells in the EC stream express COUPTFII (arrows) shown at level (i). e, Sections stained for Ki-67 and MCM2 in the CGE-remnant region in sections adjacent to one in main Fig. 5e showing cell clusters within the V-SVZ (arrows). Scale bars: 1 mm (a top row, d maps, e map), 500 µm (a insets 1,2 and 3), 100 µm (b i–xiii overviews, d top right i and v overviews, e top right ix and x overviews and bottom insets), 50 µm (b i–xiii insets, c, d i, v top right insets and i insets 1–3). Abbreviations: BLA: basolateral amygdala; CGE: caudal ganglionic eminence; DG: dentate gyrus; EC: entorhinal cortex; HP: hippocampus; ProS: prosubiculum; Sub: subiculum; tCd: tail of the caudate nucleus; tLV: temporal lobe lateral ventricle; V-SVZ: ventricular–subventricular zone.