Figure 2.

Cells with morphology and marker expression of young immature neurons are readily detected at young ages in humans. A, Schematic of coronal section in the anterior hippocampus corresponding to images in B–D. B, DCX⁺ cells (green) and Ki-67⁺ cells (red) (insets, arrows) in the human DG at birth, 3 months, and 22 months. Although there is not a clear layer of proliferating cells forming a SGZ, there is a close correlation between proliferation and the presence of immature neurons. C, Already at birth, there are patches of the DG with (arrows) and without (arrowheads) DCX⁺PSA-NCAM⁺ cells. D, At 3 weeks, regions with many DCX⁺ cells (arrows) are separated by large regions where DCX⁺ cells are absent (arrowheads). Scale bars: B–D, 100 µm; B, Insets, 50 µm; D, Insets,10 µm.