Vibration-induced startle reflex in larval zebrafish

The vibration induced startle reflex has been tracked as distance travelled (mm) in response to each stimulus (20 side-wise vibrations of 500 ms). Stimuli were interleaved by pauses of 500 ms, where no vibration was delivered.

A total of 144 fish were tested in 3 different days.
On each day, 48 fish were tested: half of them (N = 24) corresponded to the control condition (labelled as "cntrl"), the other half (N = 24) corresponded to to the experimental condition (labelled as "cncss"). The two separate groups were always tested in their respective 24-well plate, inside a ZebraBox (ViewPoint Life Sciences). The 2 groups were tested in parallel, at 6 times of the day: baseline (bsln), test1, test2, test3, test4, test5. On each day, a total of 12 tests were run: 6 tests per group. This means, the experimental design was mixed (time factor = repeated measures with 6 levels; group factor = independent measures with 2 groups). The time factor (6 levels) corresponded to different times of the day: baseline (time 0), 5 minutes later (time1), 30 minutes later (time2), 1 hour later (time3), 5 hours later (time4) and 24 hours later (time5).

On day 2 and day 3, the same test-procedure as day 1 was run again, with a different set of 48 fish (24 control, 24 experimental).
This was done to reach a larger N-size per group (24x3 = 72 per group).

The aim of the experiment was to assess whether the would be an effect of group (experimental VS control) on behaviour, over time.