Knowledge Base

Data Preparation

Track Editing

Choose Acquisition > Edit Tracks. You can fix tracking errors and swap back nose-points and tail-points that have been swapped in tracking. Normally you will not need to edit your data.

Track Smoothing

Choose Acquisition > Track Smoothing Profile > open MDM Filter 2 mm. In this profile, the Minimal Distance Moved filter is used with a value of 2 mm and option Direct selected.

Review Video and Behaviors

If you have scored behaviors manually, you can review the video and if necessary edit the data. Choose Acquisition > Score behaviors manually. For details, see Acquire Data > Score behaviors manually in the EthoVision XT Help.

Selecting Data

Choose Analysis > Data Profile. You can select (Filter) your tracks according to your independent variable values (for example, Treated animals vs. Controls) and also select parts of tracks (Nesting). This allows you to create groups of tracks to obtain group statistics for each group.

To create a group, click the button next to Common elements - Result. Connect the Start box to the new Result box. This creates a new group. Next, to specify a criterion for the new group, click an option under Filter, and insert the resulting Filter box between Start and the new Result box.

Analysis Profiles

The template experiment contains a number of analysis profiles, depending on which arena / zone template you selected in the template wizard:

• Distance & Time – With the variables Distance Moved and Velocity, the total distance moved and the mean velocity are calculated.
• Movement – The variable Movement calculates how often and how long the center-point was moving.
• In Zones – The variable In zone calculates how often and how long the subjects visited each zone in the Arena Settings. The latency to the first visit in a zone is also calculated for each subject.
• Behaviors – In this analysis profile, the frequency and duration of Body elongation and the manually scored behaviors Rearing and Grooming are calculated.

For all statistics, group means with standard errors are also calculated.

Social Interaction in Detail

The following variables are commonly used to study social interactions:

• Distance Between Subjects – Use this dependent variable to measure the average distance between the subjects. You can also use this dependent variable to determine the appropriate thresholds for the dependent variable Proximity.
• Proximity – When the nose-point of the experimental animal is in proximity relative to any of the body points of the stimulus animal, the experimental animal can be considered to be exploring or sniffing the other animal.
• Body Contact – Use this variable to quantify body contact, for example how often and for how long two animals are in contact with one another.
• Relative Movement – Use Relative movement to determine how much time the experimental animal is actively seeking contact with the stimulus animal.
• Net Weighted Movement – Net Weighted movement can be used as an objective measure for the intensity of approach and avoidance behavior.
• Weighted Movement From – Weighted movement from can be used as an objective measure for the intensity of avoidance.
• Weighted Movement To – Weighted movement to can be used as an objective measure for the intensity of approach.
• JavaScript State Variables – Additional variables in JavaScript code are available to quantify social approach, leaving, social contact and following behaviour. These variables can be found in the installation package under Utilities > JavaScript custom variables, and are also available on my.noldus.com or on the GitHub repository: https://github.com/noldus/EthoVision-JavaScriptCustomAnalysis

See Dependent Variables in Detail in the EthoVision XT Help for details. Also see the analysis profile Social - Nose to Tail in the sample experiment Social Interaction XT180, available for download from the Noldus website.

Statistics and Charts

Choose Analysis > Results > Statistics & Charts, then click Calculate. The Trial Statistics tab shows the results per trial. The Group Statistics tab shows the statistics and charts from the summarized results over all trials or the groups defined in your Data Profile.

Visualizing Data

Choose Analysis > Results > Plot Integrated Data. Select a trial from the list on the tool bar. The video file and the Time Event Plot are displayed. You can select other data/analysis profile combinations from the lists on the tool bar.

Choose Analysis > Results > Plot Heatmaps to create heatmaps of the location of your animals during the test.

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