3H-thymidine injections from E17 to E18 and survival to postnatal day (P)5 (posterior coronal)
Figure 59. This slice through the olfactory peduncle includes the main olfactory bulb (MOB) medially, the accessory olfactory bulb (AOB) dorsally, and the anterior olfactory nucleus (AON) laterally. In the AOB, the output neurons stand out as the biggest unlabeled population; the granule cells are heavily labeled, but there are more unlabeled cells than in the E16 to E17 injection group (Fig. 43); small cells throughout the rest of its layers are nearly all labeled. Labeling patterns in the MOB are nearly identical to the patterns in the more anterior slice in Figure 58. Many labeled young neurons and neuronal precursor cells in the rostral migratory stream are migrating into the MOB granular layer and periglomerular layers (arrows). Most of the tiny cells are migrating forward to the anterior MOB. Many cells in the AON are labeled on the morning of E17, but there are some unlabeled cells in the pars externa and in superficial parts of the pars lateralis.