Fig. 1.
Schematic of cTRIO for neural circuit tracing. In X-Cre mice, CAV2-DIO-Flp is injected into region C, while AAV-fDIO-TVA/G and EnvA-RV-ΔG are injected into region B. Only the presynaptic inputs to neurons that are located in region B, project to region C, and express geneX (orange cell in region B) will be retrogradely labelled by RV (green cell in region A) (A → BX+ → C). However, presynaptic inputs to region B neurons that innervate region C but do not express gene X (grey cell in region D) (D → BX− → C), or region B cells that do not project to region C (B → E) will not be labeled.