Figure 7. Many of the commissural axon-associated growth cones in Math1/L1 embryos display a swollen/bulbous morphology typically associated with a stalling behavior.
(A, B) Photomicrographs of DiI-labeled axons in open book preparations derived from E12.5 Math1/L1 embryos. (A) This particular open-book preparation contains examples of both swollen/bulbous, stalled growth cones (black arrowheads) and commissural axons tipped by wild type-like growth cones (white arrows) that inappropriately turn into the longitudinal plane on the ipsilateral side of the FP. (B) In this open-book preparation, there are at least four examples of presumably stalled growth cones (black arrowheads). In each panel, the dashed lines demarcate the position of the FP. Ipsi, ipsilateral; ant, anterior direction. Scale bar in (B), 25 μm (A, B).