Position of fluorogold (FG) injection sites in the locus coeruleus (LC). Panel A shows a coronal section through the dorsal pons with the LC and adjacent anatomical structures. The visible neurons and fibers are from native GFP fluorescence of the GAD67-GFP knock-in mouse. Panel B shows a FG injection site and the radius of tracer diffusion. Panel C is a schematic drawing from “The mouse brain in stereotaxic coordinates”, (K. Franklin at al., 2008) that shows the four injection sites in different shades from animals included in the analysis of LC afferents. The three Xs indicate the injection sites of animals that were excluded from analysis. Abbreviations: 4V – fourth ventricle, 7N – seventh cranial nerve, Bar – Barrington nucleus, LC – locus coeruleus and MPB – medial parabrachial nucleus. Scale bar = 500 μm.