Extended Data Fig. 5: The EC stream supplies interneurons to the temporal lobe.

a, Coronal section at birth showing DCX⁺DLX2⁺TBR1⁻ cells with processes emanating at a branch-point (arrow) from the EC stream (1) and a stream cluster branch-point (arrow) away from the ventricle (2). b, DCX⁺ cells in the EC stream clusters at birth are DLX2⁺COUPTFII⁺ at distal, middle, and proximal distances from the tLV. Cells can be observed sending processes out of the dense cell clusters toward the EC (arrow). c, In the same section as b, the lateral wall of the tLV contains large collections of DCX⁺DLX2⁺COUPTFII⁺ cells. d, At 7 months of age, individual DCX⁺DLX2⁺ cells are found ventrally to the tLV (arrows). e, At 7 months the EC stream contains DCX⁺DLX2⁺TBR1^– cells (arrows). f, At birth, the macaque temporal lobe V-SVZ contains cell clusters with DCX⁺DLX2⁺ cells that are COUPTFII^– (arrowheads), and COUPTFII⁺ (arrows). g, At 7 months the EC contains DCX⁺DLX2⁺TBR1^– cells (arrows). h, In the EC at 38 GW, DCX⁺ cells can be observed that co-express the cortical excitatory neuron transcription factor TBR1. These cells typically had a rounded morphology (arrows) and lacked migratory features. i,j, Quantifications of marker co-expression by cells in the EC stream and in the EC between birth and 11 months for DCX, PSA-NCAM, and COUPTFII (i) or in the EC stream for DCX, PSA-NCAM, and DLX2 (j). Scale bars: 1 mm (a), 100 µm (a insets 1 and 2, b top row, c top, e top and middle left, f left overview and inset overviews 1 and 2, g left), 50 µm (b bottom row, c bottom, d top, h), 20 µm (f insets), 10 µm (a bottom right insets, d bottom, e right, bottom, and bottom right insets, g insets i and ii). Abbreviations: BLA basolateral amygdala; EC: entorhinal cortex; HP: hippocampus; tLV: temporal lobe lateral ventricle.