Extended Data Fig. 4: EC stream neurons express COUPTFII between 38 GW and 11 months.

a, Map at 38 GW of DCX⁺COUPTFII⁺ cell clusters in a coronal section at the level of the anterior tip of the temporal lobe lateral ventricle (tLV) as shown in Fig. 1d. DCX⁺COUPTFII⁺ cells are located within and emanating from dense streams (arrow) at this age alongside individual DCX⁺ cells (arrowheads). b, At 38 GW, DCX⁺SP8⁺ cells individually migrating (arrowheads) and within the EC stream (arrow) are infrequent (~2%). c, Coronal map at 38 GW of the cell clusters shown in Fig. 1b from a level caudal to the map in (a). These DCX⁺ cells are COUPTFII⁺ and the stream directed to the EC breaks away from the ventricle at its closest point to the EC. d, Sagittal maps at 10 days postnatal spaced by 1 mm showing the whole tissue sections that are magnified in Fig. 1e. Dense DCX⁺COUPTFII⁺ cell clusters are present between the ventricle and EC and processes and individual cells are visible extending from the clusters (arrows). e, DCX⁺PSA-NCAM⁺ COUPTFII⁺ clusters in the EC stream at 7 months and 11 months and low magnification views of the magnified region shown (inset). f, Immunostaining of DCX⁺ cells in the EC stream at birth shows a small subset co-expressing PROX1 or LHX6. g, The percentage of DCX⁺ nuclei in the human EC between birth and 2 years; n = 3 individuals across 2 independent experiments, data points are individual images, large dots and bars are mean values +/− SD for each individual. h, COUPTFII^– DCX⁺ cells in the human RMS at 39 GW. i, At birth in the macaque, immunostaining in the temporal lobe V-SVZ and EC stream region shows dense DCX⁺PSA-NCAM⁺ cell clusters that do not co-express PAX6. Scale bars: 2 mm (d maps), 1 mm (a and c maps), 500 µm (a insets 1 and 2 left, c inset 2 left), 100 µm (a inset 1 middle panels inset 2 right panels, b top row, c inset 1, e inset), 50 µm (c inset 2 right panels, d bottom row, f, h, i), 20 µm (a inset 1 right, b bottom row, e high magnification view). Abbreviations: BLA basolateral amygdala; EC: entorhinal cortex; HP: hippocampus; PL: paralaminar amygdala; RMS: rostral migratory stream; tLV: temporal lobe lateral ventricle; V-SVZ: ventricular–subventricular zone.