motor axons + PNS-stage 14

Here we see 1D4 + 22C10 staining at a stage at which the motor axons have not yet reached the dorsal cluster of PNS neurons. 1D4 still stains epidermis at this stage. In the first focal plane we seen the motor axons (ISN) just touching the lateral chordotonals in the middle segment. The PNS axons from the dorsal cluster in this segment are growing proximally and have just reached the lateral chordotonals. In the right-hand segment the motor axons have apparently not yet reached the lateral chordotonal, but this cell has extended an axon which is touching the terminus of the motor axon tract. The fact that the sensory axons are present in two of the segments shown here in the region between the dorsal cluster and the black structure (m cell?) along the ISN, while the motor axons have not passed the m cell in the first and third segments and have just reached the lateral chordotonal in the middle segment, suggests that the sensory axons have pioneered this section of the pathway. In the left-hand segment neither motor nor sensory axons are visible in the vicinity of the lateral chordotonals.

To stage 15 motor axons + PNS

To early 17 motor axons + PNS: dorsal region

To early 17 motor axons + PNS brightfield

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