Figure 17
High power views of the hemiellipsoid body to reveal the lamellar organization of the cap and core neuropils. Triple labeling for synapsin immunoreactivity (SYN; red), RFamide-like immunoreactivity (RF; green), plus the nuclear marker (NUC) shown in conventional fluorescence combined with the Apotome structured illumination technique (A-C) and confocal laser scan microscopy (D1–D4). A: the position of sections D and D1–D4 is indicated here. The cluster of lateral protocerebral interneurons (LPI) is identified. B: transverse section of the hemiellipsoid body demonstrating the arrangement of the cap (Cap), core 1 (Co1) and core 2 (Co2) neuropils as well as the intermediate layers 1 and 2 (IL1, IL2; the dotted lines delineates a damaged region of the tissue). The extensive cluster of lateral protocerebral interneurons (LPI) is seen to stretch around both sides of the hemiellipsoid body. C: A tangential section with the nuclear counter stain reveals the presence of cell nuclei that are interspersed in the core 1 neuropil, presumably belonging to endothelial cells of blood vessels. In addition, the interface between intermediate layer 1 and core neuropil 1 is lined with cell nuclei (arrows). The extensive cluster of lateral protocerebral interneurons (LPI) stretches around the hemiellipsoid body. D1–D4: a series of tangential optical sections through the hemiellipsoid body (the positions are indicated in A). Note the lamellar organization of the cap and core neuropil. The entire image stack is composed of 29 optical sections of 0.76 μm thickness covering z = 21.2 μm. The four single images are projections of 3 optical sections covering z = 0 – 1.5 μm (D1; the most superficial section), z = 3.8 – 5.3 μm (D2), z = 9.1 – 10.6 μm (D3), and z = 18.2 – 19.7 μm (D4). The Cap (Cap) and core 1 (Co1) neuropils are visible as well as the intermediate layer 1 (IL1). The insets in sections D1–D3 demonstrate the string-like arrangement of tiny RFir profiles in the cap neuropil which are arranged parallel to the lamellae, and the inset in D4 shows similar profiles in the core neuropil 1. In sections D3 and D4, strands of lightly synapsin immunoreactive material seem to span across the intermediate layer 1 (arrows in D3). The dotted line in D4 identifies that sector of the core 1 neuropil that is strongly invaded by RFir fibers.