Knowledge Base

Nesting vs. Nesting over Subjects

Aim

To select track segments based on the behavior of one or more subjects. In experiments with multiple animals per arena, the Data profile offers two types of nesting options.

Prerequisite

• You have the Social Interaction Module.

Nesting

To analyze the track segments of a subject based on that subject's behavior, choose an option under Nesting, and follow the procedure on How to Select Track Segments.

Result: Each subject will be analyzed in different track segments (intervals), according to its own behavior (see B in the figure below).

Nesting over Subjects

To analyze the track segments of a subject based on the behavior of a specific subject (or combination of subjects, called Actors), choose an option under Nesting over Subjects, and select the Actors.

Result: Within the same arena, subjects will be analyzed in equal track segments, according to the behavior of the Actors (see C and D in the figure below).

Notes

• Arenas are independent replicates. Therefore, nesting intervals are applied to each arena separately depending on the state of their subjects.
• Selecting Time under Nesting or Nesting over Subjects makes no difference, because within one arena the tracks of multiple subjects start at the same time.

Effect of Nesting in One Arena with Three Animals

Dotted lines: tracks. Black bars: time intervals when a behavioral state or Trial Control state is active (for example: In zone for the variable In zone, or Highly mobile for Mobility). White bars: data selected for analysis. A: Original data. B: Results of Nesting. Track segments are selected according to the state of the corresponding subject. C: Results of Nesting over Subjects, with one subject selected in the Actors tab. D: Results of Nesting over Subjects, with two or more subjects selected in the Actors tab. For reasons of space, the combinations "Any/All of Subjects 1 and 3" and "Any/All of Subjects 2 and 3" are not displayed.

Nesting over Subjects

Aim

To analyze the track segments of a subject based on the behavior of a specific subject or combination of subjects, called Actors. This option is only available if you track two or more subjects simultaneously in the same arena.

Procedure

1. In the Data profile, choose the variable under Nesting over Subjects.
2. Click the Actors tab of the nesting window.
3. Select the actors of the behavior defining the interval. Select the subject that should show the behavior of interest. If you select two or more subjects in the Actors tab, select one of the two options from the list immediately below the Subjects box:
   • All selected subjects: To analyze the samples when all the actors show that behavior simultaneously.
   • Any selected subject: To analyze the samples when at least one actor shows that behavior.
4. If the Actors tab also contains the Body points options, select one or more body points of the subjects selected above.
5. For the dependent variables of social interaction, a Receivers tab is also available. Receivers are the subjects towards which the behavior of the Actor is directed. For example:
   • To analyze when Subject 2 is moving to Subject 1, Subject 2 is the Actor and Subject 1 is the Receiver.
   • To analyze when Subject 1 is in proximity of Subject 2, Subject 1 is the Actor and Subject 2 is the Receiver.
   Click the Receivers tab and select the subjects that you want to define as Receivers.
6. Click OK. Proceed with step 4 in How to Select Track Segments.

Important: Be careful when selecting the same subject under Actors and Receivers. In such a case you may also get unwanted selections, for example Subject 1's nose point (Actor) In proximity of Subject 1's tail base (Receiver). The resulting selection has little meaning.

Examples

• Social interactions. You want to analyze the time that the nose-point of Subject 1 was in proximity of the tail-base point of Subject 2 (ano-genital sniffing).

  Solution: Subject 1 is Actor, Subject 2 is Receiver.

  • Under Nesting over Subjects, click the button next to Proximity.
  • In the Actors tab select Subject 1 and deselect Subject 2. Under Body points, select Nose-point only.
  • In the Receivers tab select Subject 2 and deselect Subject 1. Under Body points, select Tail-base point only.

  If you want to select the time that the nose point of Subject 1 was in proximity of the tail-base point of Subject 2, or vice versa, create two nesting boxes, one that specifies Subject 1's nose in proximity of Subject 2's tail base, and the other that specifies Subject 2's nose in proximity of Subject 1's tail base. Next, combine the two boxes with OR logic (see Basic Rules for Combining Selection Boxes).

• One Actor, no Receivers. You want to select the track segments when Subject 2 was moving, and quantify the distance moved by other subjects in that period of time.

  Solution: Subject 2 is the Actor. Under Nesting over Subjects, click the button next to Movement.

  • In the Actors tab select Subject 2 and deselect the other subjects.
  • In the Analysis profile, select Distance moved. The statistics results refer to each subject in the specified interval.

Results per Time Bin

Aim

To split tracks into segments of equal duration. You can then show results for each time bin. Time bins are different from Nesting over time.

Procedure

1. In the Data profile, click the Settings button on the Result box. If your data profile contains more Result boxes, open the one corresponding to the data you want to be split in time bins.
2. In the Result Settings window, select Results per time bin.

Source: EthoVision XT 19 Help - Analyze Track Segments, Noldus Information Technology