Fig. 3

Mono-synaptic retrograde labeling of LHA input circuits using rAAV2-retro-YFP, RV-∆G-EGFP, and green retrobeads. (a) Schematic diagram of tracer injection into the lateral hypothalamic area (LHA). (a’-a”’) The injection sites of rAAV2-retro-YFP, RV-∆G-EGFP, and green retrobeads were confirmed to be localized in the LHA. (b-b‴) Retrograde labeling of the MPA was observed for all three tracers. (c-d′) Retrogradely labeled neurons were observed in the mPFC following injection of rAAV2-retro-YFP (C, C′), while no such labeling was observed in the NAc (C, C”) or PVN (D, D’). (e-f’) Neurons retrogradely labeled with RV-∆G-EGFP were localized in the NAc (E, E”) and PVN (F, F’), but were barely observed in the mPFC (E, E’). (g-h′) Green retrobeads retrogradely labeled the NAc (G, G”) and PVN (H, H’), but not the mPFC (G, G’). (i) The number of labeled neurons in each upstream region of the LHA was compared among the three tracers. Three mice were analyzed for each viral tracer or retrobeads. Scale bars = 1 mm for A′-A‴, C, D, E, F, G, H; 200 μm for the magnified images