Knowledge Base

Arena Settings

Create an experiment. For details, see Chapter 1 of this manual, or in EthoVision XT press F1 and see Setup an Experiment in the EthoVision XT Help.

Choose Setup > Arena Settings > ...

The zone groups in your experiment depend on what zone template you chose when creating the experiment.

• Platform, Quadrants – This zone template creates one arena settings profile with a zone group Platform with zones Platform and Platform Zone (the zone around the platform) and a zone group Quadrant with a zone for each quadrant.
• Platform, Quadrants, Corridors, Border – This zone template creates four arena settings profiles, one for each quadrant. The South-West Platform profile, for example, contains a zone group Platform with zones Platform and Platform Zone (the zone around the platform), a zone group Quadrant with a zone for each quadrant, a zone group Thigmotaxis with zone Border Zone, and a Whishaw's corridor for the other quadrants than the one with the platform.

Whishaw's corridor is an 18-centimeter wide path from the starting location to the platform. This corridor is designated as the correct route and if a rat deviates from this route at any point it receives a maximum of one error on that trial (Whishaw's error). To be able to determine whether the animal deviates from this route, you should define the rest of the arena as an Outside corridor zone. A Whishaw's corridor is defined for each release point you use. By creating separate Arena Settings for each corridor, you can select the appropriate Arena Settings for data acquisition depending on the release point for that trial.

To resize and reshape a zone, click first the Point edit mode button on the toolbar, then move the corners of the zone outline. Hold Shift to keep the same aspect ratio of the shape. Hold Ctrl to enlarge/reduce the shape size in all directions.

Zone for Analyzing Thigmotaxis

To quantify thigmotaxis, that is, persistent swim along the wall of the pool, create an additional zone group, and draw a circle which should be the internal margin of the zone. Place the zone label between this circle and the outline of the arena.

Trial Control Settings

In the Trial Control Settings you can define conditions for the start and stop of the track.

Choose Setup > Trial Control Settings > Open one of the following:

• Default (No Max Duration) – When you use this profile, tracking stops when you click the Stop trial button.
• Max Track Duration 1 Min – When you use this profile, tracking starts automatically 2 seconds after the animal has been placed in the maze. The track stops automatically when the center-point of the animal has been in the zone Platform for at least 5 seconds, or when 60 seconds have elapsed since the start of the track.
• Max Track Duration 2 Min – When you use this profile, tracking stops when the center-point of the animal has been in the zone Platform for at least 5 seconds, or after 2 minutes if the animal does not find the platform within that time.

Using an Adjustable Platform

If you use an adjustable platform you can define an action to raise the platform when the animal swims around the platform. Note that you need the Trial & Hardware Control module to be able to control the platform.

Detection Settings

Choose Setup > Detection Settings > Detection Settings 1.

Check in the Video Section that the sample rate is set to 5 samples/second (for rats) or 12.5 samples/second (for mice).

Advanced Detection Settings

If detection of the subject is not optimal after using the Automated setup function, do the following:

1. Check that either Dynamic Subtraction or Differencing is selected as the detection method. Differencing is the preferred option if you work with hooded animals.
2. When using Dynamic Subtraction – Move the slider to define the animal's contrast. The animal must be fully detected in all parts of the arena and the noise must be minimal. Specify the Current frame weight. A low value (for instance, 10–20) usually works well.
3. When using Differencing – Set the Sensitivity slider. The slider determines what difference in contrast from the background is seen as the animal.

For more information, see Configure Detection Settings in the EthoVision XT Help.

Trial List

Choose Setup > Trial List.

Defining Independent Variables

Enter your independent variables such as:

• Subject ID with the ID of your animals as predefined values.
• Phase with Training and Probe as predefined values.
• Treatment with Treated and Control as predefined values.
• Dose with numerical values (e.g. 0.1 mg/kg, 0.5 mg/kg, etc.)
• Day After Treatment (with values 1, 2, etc.)
• Name of the Experimenter, etc.

Making a List of Trials

If you want, you can pre-define all your trials here. Click the Add Trials button. You can also prepare the trials in Excel, randomize them and then paste the values into your Trial List.

Specify the values of the independent variables in advance, or enter them as you carry out the trials.

Furthermore, you can define a list of trials for batch acquisition. See Batch Data Acquisition in the EthoVision XT Help.

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology