Fig. 7. In the absence of a leader axon, follower axons grow more slowly at the midline. (A) Single time point images showing a leader axon (pink arrow) that projects towards the midline and is injured right before crossing it (pink arrow with asterisk). A follower axon behind it (blue arrow) overtakes the leader axon and crosses the midline (blue arrow with asterisk). After this axon crosses the midline another axon from the left vrc also grows across the midline. The two growth cones: the new leader from the right vrc (blue arrow with asterisk) and the first axon from the left vrc have just undergone their stereotypic behavior and are not aligned with the POC trajectory until the last image where their growth cones establish contact with the opposite axon shaft. (B) Axon distance from midline along the POC trajectory graph showing three separate cases where follower axon was analyzed after the leader axon was damaged. The axon graphed in blue corresponds to the follower axon shown above (blue arrow in A).