Figure 3.

Light–dark test with 5-min intervals repeated 50 times. (a) Distance traveled by zebrafish larvae when light and dark stimuli were alternately repeated 50 times at 5-min intervals after being acclimated to a dark place for 1 h. As the number of repetitions increases, the traveled distance becomes smaller and more constant; (b) distance when the light is on and off at arbitrary numbers of repetitions (1st, 10th, 20th, 30th, 40th, and 50th). At all points, the traveled distance is larger when the light is off than when the light is on. After the 10th repetition, there are almost no changes in the traveled distance; (c) Tukey–Kramer test results; (d) Dunnett’s test results, where the 1st to 10th repetitions were extracted and tested using the 10th repetition as reference. * p < 0.05 vs. 1 (on), ** p < 0.01 vs. 1 (on), ^†† p < 0.01 vs. 1 (off) (Tukey–Kramer test). ^¶ p < 0.05 vs. 10 (off), ^¶¶ p < 0.01 vs. 10 (off) (Dunnet’s test). Values are presented as mean ± SE (n = 42).