Knowledge Base

Setting Up Your CatWalk XT Experiment

Setting up an experiment involves the following steps:

• Setting up the walkway
• Creating a new experiment
• Specifying experiment settings
• Defining the trial list

Setting Up the Walkway

1. For focusing the camera and calibration of the walkway, a calibration card is supplied. The card must be placed in the center of the walkway, separated from both corridor walls.

2. When you first start CatWalk XT, the Application Startup Tasks window appears.

3. Click Set up the Walkway.

4. The Setup Walkway Tasks dialog appears.

5. Click Focus Walkway. Follow the instructions shown on click Show Instructions. Make sure the aperture is fully opened (brightness is maximal) and focus of the camera is optimal. When finished, the green bar should be (nearly) 100%. Press Next: Calibration.

6. In the Calibrate Walkway window, a rectangle is displayed that represents the scale factors on the two axes. Click Auto Calibrate. The white rectangle will be automatically located in the correct location and will have the correct size. If auto calibration fails, a warning with instructions appears. If the calibration is OK, press Next: Define Walkway (OK) to proceed to the next step. The changes are stored.

7. In the Setup Walkway Tasks window, click Define the Layout of the Walkway. The Define Walkway dialog opens. Remove the calibration card or make sure it is not close to the walls and is in the center of the walkway. Press Detect Walkway. If successfully detected, the white rectangle will cover about 80% of the walkway and will be perfectly aligned with the side walls. If it is not detected automatically, a warning describes what is wrong. The walkway sides must be aligned with the camera image and must be parallel. If walkway detection was successful, make the white rectangle longer or shorter to define the area of the glass plate in which you want to record the paw prints of the animal. It should not be necessary to change the height of the white rectangle.

Creating a New Experiment

1. To create a new experiment, in the Application Startup Tasks window, click Create a New Experiment or choose File > New Experiment.

2. Select a Setup Profile from the list.

3. Enter the name for your experiment, accept the default location or browse to a new location, and click the Create Experiment button.

Specifying the Main Experiment Settings

You can save the current Experiment Settings, Time Points, Treatment Groups, and Trial List to an Experiment Setup Profile. You can select an Experiment Setup Profile when you create a new experiment, so the experiment settings are copied to the new experiment.

1. Choose Setup > Experiment Settings, or in the New Experiment Tasks window, click Experiment Settings.

2. Define the time points: Time points are categories that represent predefined points in time relative to the administration of the treatment or any other event important in your study. Each animal is tested at those time points. For example, Pre-treatment, Day 1, Day 3, and Day 5. Under Time Points, click the Add Time Point button to add one or more time points.

3. Define the animal type: Choose the Animal Type (Rat or Mouse). The Automatic Footprint Classification module uses a different algorithm depending on whether you select Rat or Mouse. The Sciatic Functional Index is also calculated differently for rats and mice.

4. Define the treatment groups:

   • Under Treatment Groups, click Add Group to add one or more treatment groups.
   • In the Type column, select the type of treatment group from the list (Undefined, Experimental, Sham, or Control).
   • Optionally, in the Name column, change the name of the treatment group.
   • Optionally, enter a Description for that group. This information is also shown in the export file of both the Run and Trial Statistics.

5. Define the run criteria: Under Run Criteria, ensure that all runs are executed at approximately the same speed. Specify the following run criteria:

   • Minimum Run Duration – If it takes the animal less time than the set value, the run is labeled non-compliant.
   • Maximum Run Duration – If the animal exceeds the set value, the run is labeled non-compliant.
   • Minimum Number of Compliant Runs to Acquire – Data acquisition stops automatically when this criterion is met during a trial.
   • Use Maximum Allowed Speed Variation – When selected, if the animal exceeds the set value, the run is labeled non-compliant.

6. Proceed to the Trial List by clicking >> Trial List at the bottom-right of the screen, or choose Setup > Trial List.

Defining the Trial List

In the Trial List you add trials and animals for which you want to acquire runs.

1. Click the Add Trial(s) button at the bottom-left of the Trial List screen.

2. In the Add Trial(s) window, enter the Number of Trials you want to add for each treatment group defined in the Experiment Settings and click Add.

3. Click in a cell of the Trial or Animal column to change a label. Click in a cell of the Time Point column to add a time point (day, week, etc.).

4. If necessary, re-assign a Treatment Group to a trial or animal by selecting a treatment group from the list.

5. To proceed to Detection Settings, choose Setup > Detection Settings.

To delete trials from the Trial List, click the row with the trial or animal you want to delete, and click the Delete Trial(s) button.

Experiment Setup Profile

You can save the current Experiment Settings and the Trial List in an Experiment Setup Profile, so you can re-use it when creating another experiment.

1. Choose Profiles > Experiment Setup Profile > New.
2. Select Create an Experiment Setup Profile from the current experiment.
3. Enter a name and click Add.
4. If necessary, make adjustments and click OK to store the profile.
5. When creating a new experiment, select that Experiment Setup Profile.

Source: CatWalk XT 11.0 Quick Start Guide, Noldus Information Technology