NeuroFIG 29: The cells of the cephalic sensilla.
A. Graphic rendition depicting the cells of the left-side cephalic sensillar cells (right CEPsh cells are shown to add dimension). The four CEM neurons are only found in males. The mechanosensory CEP neurons are set in fourfold symmetry close to the NR (only left-side neurons are shown). Each CEP neuron sends a dendrite to the lips within a labial process bundle and an axon into the NR to make synaptic connections with many partners including their contralateral homologs (White et al., 1986). The four cephalic sheaths are the only bipolar sheath cells. Each extends an anterior CEP dendrite-associated process and a thin, sheet-like posterior process that envelops a quadrant of the NR. The four cephalic socket cells are localized at the posterior of the anterior bulb in fourfold symmetry.
B. Epifluorescent image from an animal expressing the reporter gene hlh-17::GFP. Anterior processes (gray arrows) of the CEPsh cells (gray arrowheads) terminate in a goblet-like shape as part of the CEP sensilla. The posterior process (white arrows) surrounds part of the NR as well as the anterior extremity of the VNC. (Top animal) The right-side cells as seen from a lateral view (also note that ventral is top in this animal). (Bottom animal) Ventral view. (Insets) The sensillar endings of the sheath cells from a different level in each animal. Magnification, 400x. (Strain source: Casonya Jackson.)
C. Epifluorescent image from an animal expressing the reporter gene dat-1::GFP. Cephalic neurons with anteriorly directed dendrites (thin arrows) and posteriorly directed axons (thick arrows), left lateral view. Magnification, 400x. (Strain source: S. Clark.)
D. Image of the same animal as in C from a different level. Magnification, 600x.
E. Epifluorescent images from an animal expressing the reporter gene hlh-17::GFP in sheath cells, left lateral view. (Top panel) DIC/GFP images merged to display the cell body positions. (Bottom panel) GFP image only. Magnification, 400x. (Strain source: C. Jackson.)
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