Knowledge Base

Trial Control Settings

Default Trial Control Settings

Choose Setup > Trial Control Settings > Default or White Light Routine. Depending on which template you used to create your experiment, you will find two or three examples of trial control settings:

• Default – The default Trial Control Start-Stop rule. Use these settings to start and stop tracking manually.
• White Light Routine – Use these settings when you want to provide a light stimulus during the trial. Ten minutes after the start of the trial, the DanioVision white light immediately turns on to 100% intensity for 10 minutes, then the white light immediately turns off for 10 minutes. This sequence of actions is repeated twice, using a sub-rule, after which the trial stops.
• Tapping Stimulus Routine – These settings contain a routine to produce a recurrent Tapping stimulus.

Maximum Trial Duration (Recommended)

• If you record video: 60 minutes.
• Without recording video: 72 hours.

You can in principle record video for more than one hour, however consider that DanioVision creates high quality video files, which occupy a large disk space. Depending on the frame rate and resolution, one hour of recording may require more than 1 GB.

Set the duration of your trials in the Maximum Trial Duration pane or in the Start-Stop trial rule, by placing a Time condition immediately before the Stop Track action box.

Tested Configuration

• Camera video resolution: 1280 x 1024
• Operating system: Windows 11 Pro, 24H2
• Software: EthoVision XT 18.0
• Experiment: DanioVision with 96 wells
• Trial Control: Two sub-rules, one for the Tapping device and one for the White Light. One action every five minutes, for 30 minutes total per device type. Total duration of the test: two hours.

Create Your Own Trial Control Procedure

Aim

You can adjust these trial control settings to your own needs. The procedure below describes how to define Trial Control Settings from scratch.

Example

A researcher wants to expose the larvae to alternating periods with the white light on and off, in which the light-on periods also vary in intensity.

To program this schedule:

1. To open the Trial Control, in the Experiment Explorer, right-click Trial Control Settings, select New, enter a name and click OK. The Trial Control screen opens with the default Start-Stop trial control rule.
2. Click the Condition box with Infinite Time and press Delete.
3. In the Components pane, under Actions – Hardware, click the button in the Add column next to White Light Stimulus. Select Create a New Action.
4. In the Hardware Action window, set the following:
   • Action name – Enter a description of the action, for example "Light on 100%".
   • Action to perform – Select Light On from the list.
   • Intensity level – Select the maximum intensity level of the light, in percentage (0–100%) or in Steps (0–4096). With the standard White Light settings, the light intensities of the white light are approximately:
     • 5% = 207 Steps = 139 lux
     • 25% = 1000 Steps = 2500 lux
     • 50% = 2100 Steps = 5300 lux
     • 75% = 3000 Steps = 8000 lux
     • 100% = 4095 Steps = 10500 lux
   • Fade duration – For example, with an Intensity Level of 50% and a Fade Duration of 2 seconds, the white light gradually turns on until 50% of its maximum intensity in 2 seconds. Note: if your experiment was created from a template of EthoVision XT 17.0 or an earlier version, you could only set the fade duration in seconds. In experiments created from templates in EthoVision XT 17.5 and later versions, you can set the fade duration in milliseconds, seconds, minutes, and hours (up to 24 hours).
5. Click OK and insert the Action box in the sequence.
6. In the Components pane, under Conditions, click the button next to Time. Click Create a New Action and click OK. In the Time Condition window, you can set the following:
   • Condition name – For example, enter "Wait 15 mins".
   • Condition is met – For the option After a Time Of, enter "15 mins".
7. Click OK and insert the Condition box in the sequence.
8. Repeat steps 3–6 to complete the Trial Control rule:
   • Add a Hardware Action box with White Bottom Light – Off and a Condition Time box with "After 10 mins".
   • Add a Hardware Action box with White Bottom Light – On 50% and a Condition Time box with "After 10 mins".
   • Add a Hardware Action box with White Bottom Light – Off and a Condition Time box with "After 10 mins".
   • Add a Hardware Action box with White Bottom Light – On 100% and a Condition Time box with "After 15 mins".
9. Insert all the boxes in the correct order into the sequence and make sure you connect all boxes. To connect boxes, drag the mouse from the middle of one to the middle of the other.

Tip: Combinations of Action and Condition boxes that are repeated in a sequence can be replaced with a sub-rule. This is especially useful when the entire sequence is repeated multiple times during a trial. For example: [White Bottom Light – On – 100%] > [After 10 min] > [White Bottom Light – Off] > [After 10 min]. For more information on using sub-rules, see the EthoVision XT 18 – Trial and Hardware Control – Reference Manual.

Notes

• Click Test in the Hardware Action window to test the hardware action.
• Click Reset to reset all Hardware Action windows in your Trial Control procedure to their default values. For example, a White Bottom Light action is set to off by default; however, if you set the default White Bottom Light to on, then after clicking Reset the white light switches on.
• To analyze data in the light or dark period, first create a Data Profile that specifies that period using Trial Control State, then calculate the statistics.
• For more information on Trial Control Settings, see Trial Control in the EthoVision XT Help and the EthoVision XT 18 – Trial and Hardware Control – Reference Manual. To open this manual, from the Windows Start menu choose All Apps > Noldus > EthoVision XT 18 Other Documentation.

Use an External Command

Examples of external commands include:

• Play a sound during the trial.
• Start a batch file that triggers the presentation of a visual stimulus (e.g. a looming object) during the trial.

When you work with multiple arenas, the command is executed for each arena. For example, the command to play a sound is repeated 96 times for a 96-arena experiment. To prevent this, use one of the following methods:

Method 1 – Condition in Arena 1

1. In the Arena Settings, create a zone in Arena 1 and call it "Zone 1A". Make the zone as large as the arena.
2. In the Trial Control Settings, make a condition such as "Is subject in Zone 1A?", followed by the external command.
3. Insert a condition before the External Command box that will only become true for one of the arenas, for example Arena 1.
4. Make sure that the sequence does not interfere with the rest of the Trial Control rule. Place the Condition box and the External Command Action box in a separate branch so that the execution of the external command does not influence the other actions in your trial control procedure.

Method 2 – Condition Specified in a Batch File

The Trial Control actions are by default executed for each arena independently, meaning an action would be executed as many times as the number of arenas. When using a batch file, it is possible to use an IF condition to execute a command only for a specific arena name, so the action is executed once for all arenas.

Suppose you want to execute the following command, which triggers the presentation of an image stimulus on a monitor:

D:\Software\Frameless\Frameless.exe "D:\Images\Dot.jpg" mon=2 fullscreen=yes duration=00:00:02

1. Create a text file with the following code:
   • @echo off
   • echo %1
   • IF %1=="Arena 1" ( D:\Software\Frameless\Frameless.exe "D:\Images\Dot.jpg" mon=2 fullscreen=yes duration=00:00:02 )
   Make sure that the arena name in the code matches exactly the name defined in the Arena Settings, including spaces. For example, if the name of the first arena in a DanioVision experiment is A1, enter A1 in the batch file. Save the file with the extension .bat, for example ShowImage.bat.
2. In the Trial Control Settings, create an External Command and next to Select Program to Run, select the batch file.
3. Next to Command Line Options, enter "%an%" (including the quotes). This makes EthoVision XT listen to the arena name and execute the command only for the arena specified in the batch file.
4. Arrange the External Command in your Trial Control procedure. In this example it has been placed in a sub-rule.

The stimulus is presented once every 10 seconds, regardless of how many arenas are in the experiment.

Source: DanioVision DVOC-0050 Reference Manual - Trial Control Settings, Noldus Information Technology