CellTracker™-labeled cells are found in the vascular cavity and in the neurogenic niche. A-B. Projections of confocal stacked images of neurogenic niches. A. Position of a CTG-labeled cell in the vascular cavity with all fluorescence channels merged. Ai. Glutamine synthetase (GS, left) labeling of the niche; propidium iodide (PI, center) labeling of all cell nuclei, revealing the niche cell cluster with arrow pointing to the nucleus of the CTG-labeled cell; CTG-labeled cell (right). B. In another co-cultured brain, a CTG-labeled cell (arrowhead) resides in the cavity and a second CTG-labeled cell (arrow) is embedded in the outer edge of the niche. Bi. Top, GS labeling of the niche; Middle, PI labeling of cell nuclei with arrowhead and arrow pointing to the corresponding nuclei with CTG-labeling in B; Bottom, CTG-labeled cells. Scale bars: A, 50 μm; Ai, 20 μm; B and Bi, 20 μm.