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Fig. 5
Kinetics of the rebound-evoked swim command. (A) The NpHR induced forward swimming was blocked by reactivating NpHR. Top: Without reactivation of NpHR, the animal (5 dpf) started to move 267 ± 3.5 ms (SEM) after the light had been turned off and continued to swim for 3.6 ± 0.3 s (SEM). Bottom: When the animal was re-illuminated after 248 ms, the locomotion that had started after 262 ms was blocked at t = 572 ms. (B) The amplitude and duration of the tail contractions depended on the re-illumination time point. Early re-illuminations permitted only smaller amplitudes (see also Movie S4). Images are an average-z-projection of four consecutive minimum-intensity-z-projections. (C) The time difference between the cessation of locomotion and the re-illumination is plotted versus the re-illumination time point. Intervals shorter than 190 ms never permitted tail contractions. Between 190 ms and 250 ms the time difference increased rapidly and approached a maximum value of 263 ± 14 ms (SEM) at 300 ms. Trials in (B) are labeled with an asterisk in (C). (D) In ChR2 expressing animals, the response latency depended on the illumination intensity. Stronger illuminations elicited shorter latencies. Trials from a single 3-dpf animal are plotted.