Newly generated cells in different layers of the olfactory bulb. a, A newborn eGFP+ PG cell (green) around a glomerulus at P109, 3 weeks after virus injection. Calretinin-labeled (red) and tyrosine hydroxylase-labeled (blue) PG cells outline the glomerulus. Scale bar, 20 μm. b, GFP+ granule cell in the mitral cell layer (red, Nissl staining; P52, 37 d survival). Scale bar, 40 μm. c, GFP+ cells in the granule cell layer (red, TH; magenta, TOPRO3; P52, 37 d survival). Scale bar, 40 μm.