Figure 5.

Fos activation in LC-projecting orexin neurons. A, There were no significant correlations for the percentages of LC-projecting orexin neurons that were Fos positive and preference scores in nondependent rats. B, There were no significant correlations for the percentages of LC-projecting orexin neurons that were Fos positive and preference scores in post-dependent rats. C, Photomicrograph of a frontal section showing a typical WGA-Au injection in LC. D, A schematic of a frontal section illustrating across all cases the dense core (blue) and halo (yellow) for WGA-Au injections in LC (dorsal up). LC, locus ceruleus; 4V, fourth ventricle; SGe, supragenual nucleus; 7n, facial nerve.