NeuroFIG 7: Longitudinal nerve tracts and commissures in the body.

Longitudinal nerve tracts and commissures in the body. Excluding the VNC and DC, the longitudinal tracts have twofold symmetry (cf. NeuroFIG 2A&B). Excretory canal-associated nerves mark the midline on both sides. There are no cell bodies within the DC. VNC motor neurons, including those that send circumferential commissures to the DC, are indicated on the top panel, whereas the commissures themselves are marked on the bottom panel. The majority of the commissures run on the right side of the body. The ventral hypodermal nuclei positions (beige ovals between the motor neurons, numbered 2–10) are also shown in the top panel. PLM and PLN processes are located on the ventral side of the lateral hypodermal ridges, whereas ALM and ALN processes are located on the dorsal side of the lateral hypodermal ridges. Sublateral cords run under the body wall muscles. SDQ processes join the dorsal sublateral cords, and PLN processes travel into the ventral sublateral cords. (Bottom left inset) RVG (see NeuroFIG 8); (bottom right inset) tail ganglia (see NeuroFIG 8) that limit the VNC on anterior and posterior sides, respectively. (Based on White et al., 1986.)

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