Knowledge Base

The Trial Control Screen

The trial runs indefinitely until the condition to stop the trial is met.

Example: In a novel object test, in the Start-Stop Trial rule you have defined a condition 'stop the track when the mouse enters the zone with the familiar object'. It may happen that the mouse completely ignores the familiar object and only pays attention to the novel object. To prevent EthoVision from never stopping tracking, set a maximum trial duration.

Accessing Maximum Trial Duration

In the Trial Control Settings screen, locate the Maximum Trial Duration pane, right below the Components pane. If you do not see it, click the Show/Hide button on the toolbar and select Maximum Trial Duration.

Notes

Instead of using a Maximum Trial Duration, you can also define a condition based on time and place it immediately before the Stop Track box. However, there are two important differences:

• If you use the Maximum Trial Duration, the program counts the time from the start of the trial (indicated by the Start-Stop Trial box). A condition placed immediately before the Stop Track box instead considers the time from the start of data recording (indicated by the Start Track box). The two starting points may not be the same if you have a condition between Start-Stop Trial and Start Track that makes data recording start some time later than the trial.
• With a multi-arena setup, a Maximum Trial Duration stops the trial (and thus data recording) in all arenas simultaneously, even when data recording had started at different times. A time condition placed between the Start Track and Stop Track box instead stops data recording in one arena when the condition is met in that arena. This means that data recording can stop at different times in different arenas.

Example: You set data recording to start when the animal is detected for the first time in its arena. For this purpose, you make an In Zone-based condition. Next, you define a 5-minute Time condition and place it immediately before the Stop Track box. If the animals are detected for the first time at different times in different arenas, data recording stops at different times too, because of the 5-minute interval set for all arenas. The trial ends when the recording stops in the last arena.

The Maximum Trial Duration is not applied when you record video with the option Save Video Only, Track Later. You must stop video recording manually. When you track from the resulting video file, the Maximum Trial Duration is applied.

Source: EthoVision XT 18 - THC - Trial and Hardware Control, Noldus Information Technology