# Conditions

Aim

A Condition is a statement that EthoVision checks during the trial. When the Condition is met (True), the program evaluates the next element in the Trial Control sequence.

examples (Conditions are highlighted in italics)

▪When the rat reaches the platform, stop tracking.

▪When the mouse is detected in the open field, start tracking.

▪When the animal has visited zone A ten times, stop tracking.

To define a condition

1.Open or create new Trial Control Settings.

2.In the Components pane under Conditions, locate the type of condition you want to define. and click the button next to it.

tip Combine two or more conditions using the Multi condition. For details, see the EthoVision XT 19 - Trial and Hardware Control - Reference Manual.

3.Next to Condition name, type in the name you want to give to the condition, or accept the default name.

4.Specify the condition properties. See Types of condition

5.Enter a Comment (optional), then click OK.

6.Insert the condition box in the Trial Control rule.

Types of condition

Time

It defines a time interval that must elapse before an action be taken.

example Start tracking two seconds after clicking the Start trial button, or start tracking at 12 PM.

Time interval

This condition makes sense when it is combined with another condition.

example Stop tracking when the animal is found in Zone A (In zone condition) between 5 and 10 minutes (Time interval condition).

Trial Control variable

To create a condition that is met when a Trial Control variable has a certain value, or a value within a range, or equal to another variable at the time the condition becomes active. See also To define a Trial Control variable

For the meaning of becomes active, see How the trial control instructions are executed .

example Stop tracking when the variable Counter is greater than or equal to 10.

Dependent variables

To define a condition based on the behavior of the subject. This also includes behaviors scored manually. Choose one of the dependent variables to create the condition.

example 1 In zone condition. Stop tracking when the subject visits the target zone 10 times.

example 2 Movement condition. Stop tracking when the subject has been in the Not moving state for more than five minutes.

example 3 Multi condition. Stop tracking when the subject has explored an object for more than 5 minutes. Here, “explored” is defined with a Multi condition: (a) the subject’s nose point is the object zone AND (b) its head is directed to the object. When the two conditions are met simultaneously for a total of 5 minutes, the trial stops.

Hardware

To define a condition based on the signal given by a hardware device. To use hardware-based conditions, you must have the Trial and Hardware Control Module. See the EthoVision XT 19 - Trial and Hardware Control - Reference Manual.

Notes

▪If the Add a condition window appears, it means that there is at least one condition with the same name in your experiment. Create a new condition, or re-use the existing condition. See Re-use trial control elements.

▪For a complex condition like “stop the trial when the rat reaches the platform or it has been swimming for 60 seconds”, see an example for the Start/stop the trial in the Morris water maze test.

▪Trial Control conditions cannot be defined based on behaviors scored automatically with Rat or Mouse Behavior Recognition. This because the detection of behavior also depends on video frames that come after the time that the condition is evaluated.

▪If you insert a Condition box based on Activity, and then deselect Activity analysis in the Experiment settings, your rule becomes invalid. The Condition boxes based on Activity are removed from your sequence and the connecting arrows are removed. Re-connect the boxes.

▪See also Overview of conditions in the EthoVision XT 19 - Trial and Hardware Control - Reference Manual.