Fig. 7.

Selective projection targets of ps:LC and pfc:LC neurons. Rats (n=3) received dual injections to the lumbar spinal cord (bilateral to dorsal horn, CAV-PRS-ChR2-mCherry) and prefrontal cortex (unilateral to CG1, CAV-PRS-EGFP-2A-PSAM) allowing the comparison of the projection targets of the filled axons (after immunohistochemistry). This showed as expected that the spinal cord (A) and prefrontal cortex (B) are selectively innervated by axons originating from ps:LC or pfc:LC neurons respectively with only sporadic axons from the other module. The cerebellum (C) was predominantly innervated by the ps:LC neurons again with only sporadic fibers from the pfc:LC neurons. Examination of midbrain sections (D) showed that the dorsal noradrenergic bundle contained axons from both the pfc:LC and the ps:LC modules with some co-localization (D₂, shown as overlaid GFP and mCherry). However, in the nearby PAG (D₃) the large majority of the axons were from the ps:LC module indicting a specificity of innervation. Green and red arrows indicating GFP- or mCherry-filled axons. All scalebars=500 µm (except D2, D3=250 µm). DH – Dorsal horn, CG2 Cingulate cortex, ML – molecular layer; PC purkinje cell layer; GL – granule cell layer; vl-PAG – ventrolateral PAG, 4V – 4th Ventricle.