CatWalk XT - Introduction
Last updated: Jul 25, 2026
1 - Introduction 1.1 An introduction to CatWalk XT........................................................... How the CatWalk system works and what it does. 1.2 What's new in CatWalk XT.................................................................. What's new in CatWalk XT compared with previous versions. 1.3 Additional information........................................................................ Lists the CatWalk XT documentation, and additional help and information resources. 1 - Introduction
1.1 An Introduction To CatWalk XT
This section gives a general overview of what the CatWalk program does. We recommend that all first-time users of CatWalk read this section. For information on the history of the CatWalk system, see page 174.
Principle Of Operation
The heart of CatWalk system consists of an enclosed walkway on a glass plate that is traversed by a rat or mouse from one side of the walkway to the other. Green light enters at the long edge of the plate and is completely internally reflected. Light is able to escape only at those areas where the animal's paws make contact with the glass plate; as a result, the light is scattered. Thanks to our Illuminated Footprints™ technology, paws are captured by a high speed video camera that is positioned underneath the walkway. The video camera transforms each scene (the area in front of the lens) into a digital image (an image composed Figure 1.1 The CatWalk system. In the inset, a rat on the walkway. 1 - Introduction of discrete pixels of digital brightness values). The digital images are transferred to the computer through an Ethernet connection. The brightness of a pixel depends on the amount of light received from such an area by the camera. The Illuminated Footprints™ technology enables intensity differences to be detected between animals' paws.
Paw Detection
In order to be able to classify paw prints in the video, you first need to set the CatWalk program to distinguish between paw prints and background noise. For this you can adjust the Camera Gain and Green Intensity Threshold to set the Maximum and Minimum Green Intensity, respectively, of the pixels that comprise a paw print.
Classifying runs
The video images with paw prints are used in the footprint classification. You assign labels (for example, right hind paw, left front paw) manually or automatically to illuminated paw prints in each video image. You can also determine (Intermediate) Toe Spread, Print Length and Paw Angle with the interactive footprint measurements module. Once classification is done, the CatWalk software automatically calculates a wide number of parameters in each of the following categories: Parameters related to individual footprints: for example, initial contact of each placement of a paw, the duration of contact of a paw print with the glass plate, the width and length of a complete paw print, the intensity of a paw, the time the animal stands on a single hind paw or both hind paws, etc. Parameters related to the position of footprints: for example, stride length, base-of- support, relative print positions. Parameters related to time-based relationships between footprints: for example, footfall patterns, phase dispersions, support formulas. The Sciatic Functional Index which is commonly used as a tool for the evaluation of the recovery of the sciatic nerve. For a detailed description of all parameters calculated by the CatWalk program, see Analyze Data on page 91.
Applications
See Application examples on page 135. 1 - Introduction
1.2 What's New In CatWalk XT
For Users Of Catwalk 10.6
CatWalk Control Unit
The CatWalk Control Unit is now connected to the PC through a USB cable with connectors of type B and C.
Installation procedure
The software installation procedure has been greatly simplified. You no longer have to install and configure the Ethernet card drivers and the camera drivers separately. The new CatWalk XT installation wizard does that for you.
Software License Key
You can purchase CatWalk XT with a software license that makes it easier to use the software without worrying to lose or damage the hardware key. You can choose to have your license coupled with one computer (named Fixed license) or with multiple computers (Floating license). See Your CatWalk license on page 19 and License activation on page 23.
Data analysis: Phase Dispersions and Couplings
In the Phase Dispersions and Couplings analysis sheets, the Normal Mean has been removed from both sheets because of its problematic interpretation. A bug was fixed that caused the average CStat Mean of Phase Dispersions to fall outside the range allowed (-50 % to 75 %). See phase dispersions on page 123. In the Phase Dispersions and Couplings analysis sheets, the CStat Mean is reported within the following ranges: - For Phase Dispersions: -50 % to 50 %. Note that a value of 55 % is the same as -45 % in the circular statistics domain. - For Couplings: 0 % to 100 %. To measure the spread of data around a mean, two statistics are offered: the Angular Deviation (which is the same as the Standard Deviation in CatWalk XT 10.6 and earlier) and the Circular Standard Deviation (new in CatWalk 10.7). For the difference between the two statistics, see page 179. If the average CStat Mean of Phase Dispersions is higher than 50%, it is reported as its complementary (negative) value. For example, the values of Phase Dispersions 50, 55 and 60 would give CStat Mean = 55 %, but CatWalk XT 10.7 reports CStat Mean = -45 %, which is the complementary negative value of 55% in the circular statistics domain. 1 - Introduction
Excel sheet for calculating circular statistics
An Excel sheet has been added to your documentation that provides formulas for computing circular statistics. See page 180.
Circular charts for Phase Dispersions and Couplings
Phase dispersions and Couplings are expressed with circular statistics. Circular charts are ideal to visualize that kind of data. To facilitate interpretation of the results for those two groups of CatWalk parameters, in the Group statistics and charts screen the bar charts have been replaced by circular charts. See interpreting the circular charts on page 133.
New colors in data visualization
The colors of many charts, for example, that of footfall patterns and the timing view, have been adjusted in order to improve their accessibility to users with color vision deficiency.
1.3 Additional Information
Documentation
CatWalk XT comes with the following documentation: describes how to use the CatWalk XT system, and how to install the software and the hardware on the computer. If you purchased the CatWalk XT computer from Noldus Information Technology, all hardware and software on this computer already has been installed and tested. CatWalk XT 10.7 - Assembly Instructions.pdf. This document describes how to assemble the CatWalk system and the goal box. CatWalk XT 10.7 Quick Start Guide.pdf. This document describes how to set up, carry out and analyze an experiment with CatWalk XT.
Sample Experiments
The CatWalk XT software includes three sample experiments, which contain data collected in real experiments carried out with mice and rats. Sample experiments are a good way to start understanding gait analysis in CatWalk XT if this is the first time you operate the software. To open a sample experiment: 1 - Introduction 1. In CatWalk XT, choose Restore backup in the start screen or choose File > Restore Backup. 2. Browse to C:\Users\Public\Documents\Noldus\CatWalk XT\Experiments\Backups. 3. Select one of the files with extension CWZ and click Open. 4. Select where to save the experiment. By default, experiments are saved in C:\Users\Public\Documents\Noldus\CatWalk XT\Experiments.
The Help Menu
Help Topics - Displays the PDF of the CatWalk XT Reference Manual (F1). Tutorial videos - Opens a folder on your PC where the tutorials are stored. Noldus Online - If your computer is connected to the internet, choose this option and click one of the following items: - The CatWalk XT Home Page for general information on CatWalk and relevant publications. - Customer Support then click Support to contact the Help desk. - Knowledgebase then click Resources to search through dozens of entries in a database of questions submitted by our customers with answers by our support staff. - Report an issue to fill a form about an issue you encountered when using Catwalk XT. Deactivate License - If you have a software license, you can choose to move a license from one computer to another. Select Deactivate License on a PC in order to be able to activate the same license on another PC. See License activation on page 23. Upgrade License - If you already are a CatWalk user (XT 8/9) and you have purchased the latest version of CatWalk, choose this option to type in the new Upgrade Key number that you have received from Noldus. Enter this number in the newest software version, not the old one. If you have CatWalk XT 10.0 or 10.5, you do not need to purchase a new license. About CatWalk XT - Contains information about your copy of CatWalk XT. Click the License Info button to see the name of the d user and the license number of your software. 1 - Introduction
Noldus Help Desk
If you have any problems, questions, remarks or comments, please let us know. You can contact us at our support page: my.noldus.com We offer 24 hour support by help desks in various time zones. Before you contact Technical Support, please have the following information available. To
find this information, go to the Help menu and select About CatWalk XT:
The version number of your copy of CatWalk XT. The name of the registered user and the license number (Help > About CatWalk XT > License Info).
Other contact information
Make a PC report for the Help desk
This section is needed if the Noldus Help desk asks you to send them a PC report for the CatWalk XT computer. 1. Download the utility from the Help desk and copy it to the CatWalk XT computer. 2. Double-click on the file siw64.exe. 3. Choose File > Create Report File > HTML Report and save the file to your desktop. 4. Send the HTML file as an e-mail attachment to the Help desk.
Source: CatWalk XT 10.7 - Reference Manual