Figure 2.

Newly generated cells in the anterior SZ of the adult macaque display a neuroblast phenotype as revealed by triple-label immunofluorescence and confocal microscopy. (a–c) A sagittal section through the striatal wall of the LV provides an oblique view of the anterior SZ, revealing an extensive network of TuJ1-positive cells (red) that are distributed singly or in chain-like aggregates. Imaging in the same x, y, and z registration reveals that many of these cells are colabeled with BrdU (b and c, green) and are closely associated with GFAP-positive fibers (c, blue). The TuJ1-positive chains do not extend into the adjacent caudate nucleus (CN) or overlying cortical white matter. (d–f) The same field partially demarcated by the box in c at higher magnification shows chains and individual BrdU-labeled neuroblasts (arrows) and their proximity to the GFAP-immunopositive ependymal lining (E in f). A BrdU-labeled cell (arrowhead) that is immunonegative for both TuJ1 and GFAP may be a “type C” precursor. (g–i) A 0.6-μm-thick optical section of the same BrdU-labeled neuroblast indicated by the crossed arrow in d–f, confirming that the BrdU signal (h and i, green) is confined to the nucleus of the TuJ1-labled cell rather than to an adjacent TuJ1-negative cell. (j–l) An example of a TuJ1-postitive cell with a BrdU-labeled nucleus (arrowhead), exhibiting a bipolar morphology similar to that of a migrating neuron. A growth cone-like swelling (arrow) appears at the end of the putative thick “leading” process, and a thinner process “trails” behind. a–i show labeling 75 days after BrdU injections; j–l, 97 days after BrdU injections. (Bars = 50 μm.)