Fig. 5.

Mapping the direct projection areas of the OB using our improved monosynaptic anterograde tracing system (H129-dTK-T2 + helper AAV2/9-TK-GFP). A Timeline for mapping the direct OB output pathways using H129-dTK-T2 along with AAV2/9-TK-GFP helper. This improved monosynaptic anterograde tracing system allows for detection of postsynaptic labeled neurons with native tdTomato signals (no immunostaining enhancement). B Schema of the simplified OB projection pathways. AAV2/9-TK-GFP, 1.0 × 10¹² vg/mL, 450 nL, H129-dTK-T2, 5.0 × 10⁸ pfu/mL, 400 nL, perfusion time: day 27. C Representative image of the virus injection site in the OB. The boxed areas are presented in the right panels at a higher magnification. The starter neurons labeled by both GFP and tdTomato are indicated by white arrows. D–F Representative labeling images of the regions innervated by the OB. The boxed areas are presented in the right panels at a higher magnification. Coronal brain slices were counterstained with DAPI. LEnt, lateral entorhinal cortex; PMCo, posteromedial cortical amygdaloid nucleus.