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. Author manuscript; available in PMC: 2018 Jul 27.
Published in final edited form as: Dev Genes Evol. 2017 Jul 27;227(4):253–269. doi: 10.1007/s00427-017-0587-2

Fig. 2.

Fig. 2

Neuroblasts, lineages and initial axon projections involved in fan-shaped body formation. a. Fluorescence photomicrograph of a brain slice from a grasshopper (S. g.) at 33% of embryogenesis (e33%) following BrdU incorporation (green) showing the most medial proliferative neuroblasts in each protocerebral hemisphere (PC, outlined dashed white). Note bilateral symmetry. Fibers from progeny of neuroblasts W, X, Y, Z will generate columns of the fan-shaped body later in embryogenesis. Progeny from identified neuroblasts (1–2, 5–1, 6–1) interspersed amongst the W, X, Y, Z neuroblasts do not contribute fibers to the columnar system of the fan-shaped body and so remain beyond the scope of this study. Approximate location of the primary brain commissure (com) is indicated in each panel. Anterior (A) is to the top according to the neuraxis (n) for the grasshopper (panels a, b, d, e). b. 3D reconstruction from confocal images following DAPI staining shows the W, X, Y, Z neuroblasts (white asterisks) and their lineages (false colors are used) in the left brain hemisphere of S. g. at 35% of embryogenesis (e35%). Lineages have a stereotypic orientation in the PC. c. Confocal image of the left protocerebral hemisphere (PC, outlined dashed white) of Drosophila (D.m.) following labeling of the W, X, Y, Z neuroblasts (white asterisks) and their primary lineages by R9D11-Gal4>UAS-mcd8-GFP at stage E15. Note similarity to the organization in grasshopper (panel b). Posterior (P) is to the top according to the body axis. d, e. Initial projections into the primary brain commissure from central complex lineages prior to formation of the fan-shaped body in the grasshopper. d. 3D reconstruction from confocal images following double-labeling with 8B7 (cyan) and DAPI (grey) reveals initial projections (open white arrowheads, false color yellow) from a Z lineage are into anterior fascicles (eAC) of the early embryonic (e35%) commissural system (com) of the grasshopper. Neuraxes apply for the grasshopper. e. As for d above but showing initial projections (open white arrowheads, false color yellow) from a Y lineage are into three anterior fascicles (eAC) as well as a medial fascicle (eM) of the early embryonic (e35%) commissural system (fasle color cyan) of the grasshopper. Axons in fascicles of eAC will contribute to the fan-shaped body which forms in the region of eM. Scale bar represents 25μm in a, b, 15μm in c, 15μm in d, e. Panels a, b are modified from Boyan and Liu (2016).