Figure 7: Innervation pattern of LC neurons and the neurons in the periceruleus area by the mPFC efferents in male and female mice as detected by post-synaptic labeling using anterograde delivery of cre-recombinase.

Panels A and B show the distribution of green EGFP expressing cells in a male (A) and female (B) mouse brain; the LC borders are outlined by a white interrupted line. Panels C and D are merged images of the three channels, where the green cells express cre-driven EGFP, the red cells express the default tdTomato and the blue cells are the TH positive neurons of LC. Panel E shows the average number of EGFP cells that are colocalized with TH neurons in males and females at three different bregma levels. A higher number of green cells were counted at – 5.6 mm to bregma in male mice when compared to the female mice (P < 0.01). Panel F shows the average number of EGFP cells in the periceruleus zone in males and females at three different bregma levels where the females expressed a higher number of green cells at bregma levels – 5.3 mm (P < 0.001) and – 5.6 mm (P < 0.05) when compared to their male counterparts. It is very likely that the last group of neurons are part of the LC interface that consists of inhibitory interneurons. Scale bar = 500 μm.