Knowledge Base

Calculate the Statistics

Prepare the Tracks

A track is the group of samples acquired for a subject. You can choose to smooth the tracks to get a more reliable measure of the animal's movement path and remove the effect of outliers (caused by accidental wrong detection), random noise and body wobble.

1. Choose Acquisition > Track Smoothing Profile. Select Open and click OK.
2. Select one or more of the options: Smoothing (Lowess), Minimal Distance Moved and Maximum Distance Moved.

For information on the smoothing options, see Smooth the Tracks in the EthoVision XT Help.

Analysis Profiles

Choose Analysis > Analysis Profile. Select New, name the analysis profile and click OK. Distance moved and Velocity are predefined as dependent variables. To add a variable to the Analysis profile, click the button next to that variable.

Note: If you created the experiment from a template, it contains a few analysis profiles. For example, the Morris water maze template experiment with the platform zone template contains four analysis profiles. One of them, Latency to reach platform, contains the variables for calculating the time taken to reach the platform.

Basic Calculations

Total Distance Moved or Average Velocity

1. Open the Analysis profile.
2. If the variable is not yet listed under Selected Dependent Variables, click the button next to Distance moved or Velocity. In the Trial Statistics tab, select Total for Distance moved, or Mean for Velocity.
3. Choose Analysis > Results > Statistics and Charts.

Time in a Zone and Number of Zone Entries

In step 2 above, click the button next to In zone. Specify the zone. In the Trial Statistics tab, select Cumulative duration and Frequency.

Time Before Reaching a Zone

Click the button next to In zone. Specify the zone you are interested in. In the Trial Statistics tab, select Latency to first.

Distance or Velocity in a Zone

1. Choose Analysis > Data Profile > New or open an existing Data profile. In the Results box click Settings, then select Results per zone. Next, choose the zones you want the results for.
2. Open an Analysis profile. Choose the variable you want to calculate, for example, Distance moved. Next, choose Analysis > Results > Statistics and Charts.

Note: EthoVision XT offers a wide range of analysis variables and methods to select data.

In the results screen, the Trial Statistics tab shows the analysis results per trial, while the Group Statistics & Charts tab shows the results for all trials together, or for the groups of trials defined in your Data profile. To modify the layout of the results table, click the Layout button.

To carry out multiple calculations at once with different filters, data profiles or analysis profiles, click the Batch button.

Visualize the Data

Track Visualization

Choose Analysis > Results > Plot Tracks to view the tracks that you selected. This allows you to visually compare tracks. You can play back your tracks to see how your subjects moved.

To display the entire track, under Filter deselect the Last [ ] seconds option, then click the Jump to End button in the Playback Control window.

Integrated Visualization

Choose Analysis > Results > Plot Integrated Data to view the track with the corresponding video (when video was recorded) and the time plot of the dependent variables (velocity, etc.).

To plot a variable:

1. Open an Analysis profile and add the dependent variable you want to view.
2. Choose Analysis > Results > Plot Integrated Data.

Other Analysis Options

Heatmaps

Choose Analysis > Results > Plot Heatmaps and click Plot Heatmaps on the toolbar. With heatmaps you get an immediate impression of which area the animal spent most time in.

Select and Group Tracks

Choose Analysis > Data Profile > New.

To analyze some tracks, not others:

1. Choose one of the options under Filter. For example:
   • Choose Trial Name and select the trials you want to analyze.
   • Choose Dose (an independent variable previously defined) and choose the values of the variable you want to use.
2. Insert the Filter box between Start and Result 1.

To analyze tracks in groups:

For example, you want to compare the results for subjects treated with a drug with those for control subjects.

1. In the Trial List, make sure that the independent variable you want to use for grouping is defined, and that each trial is labeled with one of the possible values (e.g. Treated vs. Control).
2. Make a Filter for the first group based on one of the values of the independent variable, and place the resulting box between the Start and the Result 1 box.
3. To create the second group, click the Result button under Common elements. Click and drag from the center of the Start box to the center of the new Result box. The two boxes are now connected with an arrow. Next, make a filter for the second group, and place the Filter box in the middle of the second branch.
4. Choose Analysis > Results > Statistics and Charts. Click the Group Statistics and Charts tab to view the results per group.

Analyze Track Segments

For instance, visualize the data of the first five minutes of the tracks, or visualize all samples when the subject was moving or grooming.

Choose Analysis > Data Profile > New.

Nesting: To select track segments based on time, zones or states of the subject, click the appropriate button under Nesting and specify the options there. For example, to analyze the first five minutes, choose Time. Insert the Nest box between Start and Result 1.

Time Bins: To analyze the tracks split in regular time intervals, in the Result box click Settings and select Results per time bin. For example, define intervals of 1 minute each. Then, choose Analysis > Results > Statistics and Charts.

For more information, see Analyze Track Segments in the EthoVision XT Help.

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