Fig. 3. Cell proliferation and cell survival in `comma-shaped' neurogenic areas in cell clusters 9 (A–C) and 10 (D–F) after 1, 7 and 14 days of social interaction. BrdU+ cells are shown in green and H3P+ cells are shown in yellow or in orange, depending on the amount of BrdU/H3P colocalization (asterisks). Arrows indicate strand surrounding BrdU+ cells. For clarity, counted BrdU+ cells are outlined in white in B,C and E,F. Collapsed stacks of confocal images were taken at 0.5 µm intervals. The entire stack for each image was approximately 60–80 µm. Scale bar, 50 µm in all images. (A,B) Lines of BrdU+ cells are present in the ventral posterior part of cell cluster 9 and around the lateral antennular neuropil (LAN) after 1 day (A) and 7 days (B) of social interaction. BrdU+ cells were present in the same location in all cell proliferation tests irrespective of the length of social interaction. (C) After 14 days of survival time, a ball of BrdU+ cells was present in the posterior part of cell cluster 9 with a faint line of BrdU+ cells around the anterior edge of the LAN. (D–F) A ball of BrdU+ cells was present in cell cluster 10 near the olfactory lobe (OL) and accessory lobe (AL) after 1 day (D), 7 days (E) and 14 days (F) of social interaction. Regardless of the length of social interaction, all cell proliferation tests produced a ball of BrdU+ cells in the same location of cell cluster 10. As the survival time increased, the center of the ball of BrdU+ cells was fainter than the outer ring of BrdU+ cells, indicating the dilution of BrdU due to cell divisions. AL, accessory lobe; DCN, deutocerebral commissure neuropil; LAN, lateral antennular neuropil; OL, olfactory lobe.