NeuroFIG 4A-D: Asymmetries in the C. elegans nervous system.

A&B. Some neurons migrate long distances during development to reach asymmetrical target positions along the body.
A. Larval migration of Q blast cells and their progeny. The progeny that die are indicated by an “x” within a circle. (Arrows) Routes of migration of Q blast cells and their progeny.
B. CAN, HSN, and ALM neurons also migrate, but their terminally differentiated, left and right progeny are symmetrically located along the body. (Go) Gonad primordium.
C. Most neuron processes that exit the NR from the left side decussate to the right fascicle of the VNC, generating asymmetric thickness between the right and left sides of the VNC. Processes that exit from the right side of the NR do not decussate. (e) Excretory pore.
D. Left lateral-oblique view. After exiting the NR from the left side, most fibers cross to the right side (arrow), posterior to the excretory pore (e). Epifluorescent image of a transgenic animal expressing the pan-neural unc-119::GFP transgene. Magnification, 1000x. (Strain source: CGC.)

See also NeuroFIG 4E-G

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