Cytoarchitecture and gene expression of olfactory bulb (OB) and anterior olfactory nucleus (AON) at PCW 15. The sections were shown from one rostral level (a-d), two intermediate levels (e-h and i-l) and one caudal level (m-p) with different stains indicated on each panel. OB, rostral migratory stream (RMS) and AON can be identified at PCW15. Some patches in OB and AON (identified by #) express ENC1, GRIK2, LBX1, GAP43, TBR1, CDH4 and LHX2 but not CALB2. Note that the dorsal but not ventral walls of the VZ of RMS strongly expresses TBR2 whereas the whole VZ of RMS contains strong expression of VIM, LBX1 and LHX2. One patch (? in i-l) in AON appears to have a very different expression profile. MC, mitral cells; GC, granular cells; GL, glomerular layer; ep, external plexus layer; olr, olfactory recess. Bar: 200 μm in (a) for all panels.