Flocculus. Photomicrographs of orexin A fibers in the flocculus (Fl) of the Long-Evans rat (A), grass rat (B), Syrian hamster (C), and degu (D). Note higher density of orexin fibers in the degu Fl in comparison with the other three species. PFl: paraflocculus; VC: ventral cochlear nucleus. Scale bar = 300 μm.