Fig 1: Photomicrographs of neuronal connections in the SCN of WT mice. A, The images show the localization of neurons and fibers revealing AVP contacts onto VIP, GRP, CALR, and ENK neurons. B, The images show the relationship between VIP and GRP, CALR and CALR with GRP and ENK. In both panels, the first row shows confocal images of the SCN as a whole to visualize the location of each of the cell types (z-axis: 8 µm; scale bar = 100 µm; R, rostral SCN; C, caudal SCN). The images in the second and third rows have been overexposed to optimize visualization of appositions of fibers onto neurons (arrows) for each of the peptides in the first row (z-axis = 2 µm; scale bars = 10 µm).