Knowledge Base

The Experiment's Basic Properties

Choose Setup > Experiment Settings. Specify the options listed below. Depending on your EthoVision XT license, some of the options may not be available. If you created a new template experiment, you already specified most properties of your experiment.

• Video Source: Choose whether you want to track from video files or from the live camera image (Live tracking). In the latter case, select the cameras that you are going to use. If your cameras are not listed, install the camera drivers. See Camera Installation in the EthoVision XT Help.
• Number of Arenas: An arena is a closed space where subjects move. Select the total number of arenas in your camera images. For example, select 1 for one water maze or open field; select 4 for four open fields, or four PhenoTyper cages.
• Number of Subjects per Arena: Specify how many individuals per arena you want to track. Note: Because this guide applies to the Base version of EthoVision XT, it assumes that you track one subject per arena.
• Tracked Features: Select which body points you want EthoVision XT to detect: the center-point only or the center-point with nose-point and tail-base.
• Body Point Detection Technique: If you track the nose-point and the tail-base point, select which technique should be used: the contour of the subject or a trained neural network (Deep learning). The latter option only applies to rodents, and with one or two subjects per arena.
• Analysis Options: With Activity analysis, you can have EthoVision XT detect behaviors like freezing in rodents and immobility in the Porsolt swim test. With Behavior recognition, EthoVision XT detects several rodent behaviors like grooming, sniffing and rearing.
• Units: Select the measurement units you prefer.

Draw the Arena and the Zones

Tell EthoVision XT in what region in the video image the subject moves (the arena). If you created a template experiment, the arena has already been drawn in the correct shape. Change the size and/or position of the arena to match it with your video image.

To Obtain a Background Image

1. If you use video cameras for live tracking, before starting EthoVision XT power up and connect the video camera to the PC.
2. In EthoVision XT, choose Setup > Arena Settings. Open the default Arena Settings 1 or create a new one. If you are doing tracking from video files, click Browse and open the video file you want to use to draw the arena.
3. Click Grab. If possible, do so when the arena contains no animals.

To Draw an Arena

1. Click 1. Draw Scale to Calibrate in the Arena Settings window.
2. Draw a line between two points of the arena that are at a known distance from each other. In the window that appears, type in the real world distance between the two points and click OK. Optionally repeat this procedure a few times.
3. Click 2. Select Shape and Draw Arena in the Arena Settings window.
4. Click one of the drawing tools and draw the outline of the region of the video image where the animal moves. Make sure that the label Arena points to inside this region.

To Draw a Zone

A zone is a region within the arena that you may want to use for analysis or for starting/stopping data acquisition. If you created a template experiment, zones are already defined. Change their size and/or position to fit the arena, delete zones or draw new ones.

1. Click 3. Select Shape and Draw Zones in the Arena Settings window.
2. Select one of the drawing tools.
3. Draw the contour of each zone. In this example, the platform in a water maze.
4. Give the zone a name.

Note: For more details, see Arena Settings in the EthoVision XT Help. For a DanioVision experiment, see the DanioVision DVOC-0041 - Reference Manual.

Control the Start and Stop of Data Acquisition

Specify the rules that control the start and stop of data acquisition.

Default Settings

Choose Setup > Trial Control Settings. Open the default Trial Control Settings 1. Each experiment has default Trial Control settings to start tracking when the subject is detected in the arena for one second and to stop tracking manually.

If you created a template experiment, the Trial Control settings have been adjusted for that template. For instance, for the Morris water maze experiment, tracking stops either when the animal's center-point has been in the platform zone for more than five seconds, or when the animal has been swimming around for two minutes without finding the platform.

To Program the Start of Tracking

1. In the second box, click Settings.
2. If you want to start tracking when the animal is in a zone, click Settings, deselect Arena and select that zone.
3. If necessary, change the criterion to be used (for instance, Frequency instead of Duration).

To Program the Stop of Tracking

1. In the box immediately before Stop track, click Settings.
2. If you want to stop tracking after a specific time, choose After, and enter the time needed.

Note: The first box, Start Trial marks the moment when you click the Start Trial button. The Start track box marks the time when EthoVision XT starts tracking.

For more complex start-stop rules, like "stop when the subject is on the platform", replace the Time condition with an In zone condition, and specify the platform zone. For more examples, see Trial Control in the EthoVision XT Help.

Make sure that the Trial Control Settings you want to use is selected in the Acquisition settings window before you start your data acquisition.

With the Trial and Hardware Control module, you can control hardware (lights, a pellet dispenser, etc.). For instance, turn on a light when the animal enters its shelter. It also allows you to create routines, for example in conditioning experiments.

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