Fig. 6: Using the M-cell driven C-starts to monitor functional recovery during axon regrowth.

a Protocol used to monitor M-cell axon regeneration and C-start behavior over the course of 10 dpi in individual larvae. Gray areas indicate times during which larvae were fixed in low-melting agarose (10–20 min), otherwise larvae were allowed to swim freely. During the day at which specifically the GFP-filled M-axon was injured, a baseline of escape performance was first established and the immediate effect of the injury assessed. Then axonal growth was monitored on the indicated days and behavior always assayed on the subsequent day. During the behavioral assays each larva received 30 stimuli, with ten minutes between them. b Examples of escape responses recorded with digital high-speed video (3000 frames per second; every 6th frame shown; see SM2) in one individual larva prior, one day and ten days post-injury. Stimuli were given at time zero and latency (i.e., first notable movement of larva) is indicated by marking the larva red. The green boxes indicate the interval during which the larva bent maximally. Angles of turning are also indicated. These examples highlight the possibility that (i) a clear effect of injuring one single M-axon can indeed be detected and (ii) that aspects of the behavior (e.g., latency) might already be compensated in the days that follow after injury.