Knowledge Base

Data Analysis

Analysis Profiles

Choose Analysis > Analysis Profile...

The template experiment contains the analysis profiles:

• Distance, Time & Movement. To calculate the total Distance moved (a measure of activity of the animal), the mean Velocity, and the total time spent in the two states of Movement (moving and not moving). The group means with their standard errors are also calculated.
• Zone Alternation. With the variables In Zone (to calculate the frequency, total time and latency to first visit for each zone) and Zone Alternation (to calculate the number of alternations and the maximum number of alternations for that set of zone visits).

See the section below to create analysis profiles for specific tasks.

Alternation Behavior

Spontaneous Alternation

1. Choose Analysis > Results > Statistics and Charts.
2. Select the Analysis Profile that contains the Zone Alternation variable.
3. Locate the column Zone Alternation in the table.
4. To calculate the Alternation Index, divide Alternations by Max Alternations and multiply by 100.

To change the Zone Alternation definition, open the Analysis Profile Zone Alternation and double-click the variable Zone Alternation. Here you can specify which statistics you want to have. You can also enter a Zone Exit Threshold to remove false re-entries in a zone from the statistics, due to small movements of the body point near the zone borders.

For more information, see Zone Alternation in the EthoVision XT Help.

Delayed Alternation

For delayed alternation tests, Zone Alternation is not the correct dependent variable. To analyze correct and incorrect choices, use Target Visits and Errors to compare performance between trials. Because the target arm changes between trials (for trial 2, the target is the arm which was not visited in the previous trial), you must define multiple instances of Target Visits and Errors.

Whether an arm can be defined as "target" depends on the outcome of the previous trial. If the subject went to the Left arm in trial x, then for trial x+1 the target should be the Right arm, and a revisit to the Left arm should be scored as an error.

To set this up:

1. In the Trial List (Setup > Trial List), mark each trial with a variable which states which arm was the correct choice. By definition, the 1st trial of each subject has no "correct" choice (the values for subsequent trials depend on what the animal does in that trial).
2. In the Data Profile, filter the trials based on this variable. Make two Data Profiles: one for "Right Arm Correct" and one for "Left Arm Correct".
3. Create two analysis profiles. For example:
   • Analysis Profile Target Visits and Errors for when the target (correct choice) was the Left arm. The Right arm is a non-target; visits to that arm are scored as errors.
   • Analysis Profile Target Visits and Errors for when the target (correct choice) was the Right arm.

When you analyze the data, make sure to combine a Data Profile with the correct Analysis Profile.

Visualizing Data

Choose Analysis > Results > Integrated Visualization.

The first plot shows the variable In Zone defined in the Analysis Profile, where you can see which arms were visited during the trial.

The second plot shows Zone Alternation. The subject visits first the zone marked in blue, then that in red, and when the subject enters the green-marked zone, an alternation is completed. This is scored as Alternations (blue vertical segment; A). At every visit except the last two in a trial, Max Alternations is also scored (purple vertical segment; B). This marks the moment a possible alternation could have occurred. This variable is useful to calculate the Alternation Index.

The plot also includes direct revisits (for example, green > green) or indirect revisits (green > red > green; C). The more revisits, the lower the Alternation Index.

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