Figure 6

Differentiation of larval fan-shaped body primordium-innervating neurons begins during early metamorphosis. Spatiotemporal analysis of the R45F08-Gal4 expressing cells and neurites as well as their innervation of developing central complex substructures during the first 24 h of metamorphosis. R45F08-Gal4 labeling (green), DN-cadherin labeling of neuropile (magenta). Maximum intensity projections of few adjacent confocal slices taken at different depths. (A-A”’) At 12 h after puparium formation (apf) the R45F08-Gal4-labeled cells, located at the dorsomedial region of the brain cortex, bypass the protocerebral bridge and their fascicles project through midline chiasma and enter the developing fan-shaped body, whose two halves have fused, via the medial root of fan-shaped body (mrFB), the lateral root of the fan-shaped body (lrFB), and the dorsolateral root of the fan-shaped body (dlrFB). The labeled fibers arborize in the developing fan-shaped body and form eight (2 × 4) columnar innervation domains. Labeled fibers are not evident in other neuropiles. (B-B”’) At 18 h apf the R45F08-Gal4-labeled cells as well as their innervation of the developing fan-shaped body are largely unchanged as compared to 12 h apf. (C-C”’) At 24 h apf the R45F08-Gal4-labeled cells continue to project via midline chiasma and innervate eight columnar domains of the fan-shaped body, which has grown and become more bent. In addition sparse labeling is seen at the lateral edges of the developing (and yet unfused) ellipsoid body. In (A”-C”) asterisks indicate one labeled columnar domain in two layers of the fan-shaped body. AL, antennal lobe; CX, calyx; dlrFB, dorsolateral root of fan-shaped body; EB, ellipsoid body; FB, fan-shaped body; LAL, lateral accessory lobe; lrFB, lateral root of fan-shaped body; ml, medial lobe; mrFB, medial root of fan-shaped body; NO, noduli; PB, protocerebral bridge; p, peduncle; sp, spur of mushroom body. Neuroanatomical nomenclature according to[3, 40]. Scale bars, 25 μm.