Figure 1.

The presence of newly generated cells in the dentate gyrus of adult macaque monkeys, as revealed by independent immunohistochemical markers. (a and b) The hippocampal dentate gyrus 2 hr after the last of five daily injections of BrdU shows BrdU-labeled nuclei (arrows) in the subgranular zone of the granule cell layer (G). H, hilus; M, molecular layer. (b) A BrdU-labeled “doublet” in the SGZ, possibly the daughter cell progeny of a recent mitotic event. (c) A BrdU-labeled nucleus deep in the GCL, 27 days after a single BrdU injection. Note the rounded appearance, similar to that of neighboring granule neurons and oligodendrocytes. (d) An example of a PCNA-immunopositive doublet in the SGZ. [Bars = (a) 50 μm; (b–d) 10 μm.]