Methacrylate-embedded E20 embryo in the horizontal-coronal plane (anterior)
Figure 119. This is a slice through olfactory bulb in an E20 specimen cut an an angle between the horizontal and coronal planes. The layering is very like what will be seen in the coronal plane in Figures 121 and 122. In this slice, the lumen of the olfactory recess is nearly obliterated by a large mass of shed cells. The outer limits of the NEP, the SVZ and the presumptive MOB granule cell layer are surrounded by dashed lines because there is no definite border. The internal plexiform layer of the AOB and MOB are continuous and contain many spindle-shaped migrating cells in a circular array beneath the mitral cell layer. Large tufted cells populate the external plexiform layer, and small cells are interspersed between fibers in the olfactory nerve and glomerular layers. The clump of AOB output neurons is rather small in this slice because we are in front of the main part of that structure.