Figure 18From: A comparative analysis of the distribution of immunoreactive orexin A and B in the brains of nocturnal and diurnal rodentsDorsal raphé nucleus. Photomicrographs of orexin A fibers in the dorsal raphé nucleus (DR) of the Long-Evans rat (A), grass rat (B), Syrian hamster (C), and degu (D). 4: trochlear nucleus; Aq: cerebral aqueduct. Scale bar = 300 μm.Back to article page