2 hr-survival after a single 3H-thymidine injection on E20 (sagittal)
Figure 111 is a sagittal slice through the olfactory bulb and nasal cavity in an E20 embryo exposed to 3H-thymidine 2 hrs before death. The NEP and SVZ are active proliferation zones throughout all parts of the forebrain. Labeled cells outside the NEPs and SVZs are locally multiplying glial precursors. Locally-multiplying glia in the olfactory nerve also have heavy label uptake, and the olfactory epithelium is actively proliferating with two different populations (superficial and deep) of proliferating cells.