Most interneurons in the adult human OB express Sp8. A, DAPI-stained coronal section of the adult human OB. B, Higher-magnification image of the boxed area in A shows the GCL, EPL, and GL of the OB. C–E, G, The majority of NeuN+ (C), CR+ (D), CB+ (E), and TH+ (G) cells expressed Sp8. Very few PV+ cells (F) were in the GCL and GL, and none were in the EPL; they did not express Sp8. H, Quantification of the above double-immunostaining experiments. Scale bars: A, 500 μm; B–G, 50 μm.