24 hr survival after a 3H-thymidine injection on E17 (posterior coronal)
Figure 77. A posterior coronal slice through the olfactory peduncle that contains the AOB in a dorsal position, the MOB medially, and the presumptive AON laterally in an E18 embryo—the same specimen as in Figure 76. Most cells in the parenchyma are unlabeled, the few labeled cells are most likely locally-multiplying glia. The AOB has a densely-packed layer of output neurons, surrounded by loosely-packed cells in the internal and external plexiform layers. A small group of unlabeled cells outside the olfactory SVZ may be the AOB granule cells. In the MOB, the mitral cell layer is not distinct, but is most likely the more densely packed cells in the outer part of the internal plexiform layer. The olfactory nerve is full of labeled glial cells that sharply differentiate it from the fibers in the cell-sparse external plexiform layer. The olfactory epithelium and Jacobson’s organ are full of labeled cells, indicating active proliferation.