The GFI interacts with the GFC neurons at the inframedial bridge. Gal4 lines driving UAS-mCD8::GFP (column 1) intersect with the GFI axon revealed by injection of TRITC (column 2), at the GFI IB and the GFI axonal bend (merge, column 3). The first two columns use depth color coding to represent the Z-position within the TG, with more dorsal regions displaying cool colors and ventral regions displaying warm colors (see color scale bar in A, column 2). Arrows indicate overlapping membrane contact between GFCs and GFI at the IB. Arrowheads indicate GFC contact at the GFI axon bend. All injected flies are female. A, GFC1 (78A06-Gal4) interacts with the GFI exclusively at the IB. B, GFC2 (73C07-Gal4) interacts with the GFI at the IB and the GFI axonal bend. C, GFC3 (24H07-Gal4) interacts with the GFI extensively at the IB and the GFI axonal bend. The GFI also produces small side projections that contact GFC3 (inset, arrowheads). D, GFC4 (42A06-Gal4) interacts with the GFI at the IB.