Knowledge Base

Raw Live Mouse Tracker Data

Aim: You can use the following variables to analyze basic events in the Live Mouse Tracker datasets. For example, Contact events.

Approach

Definition and Calculation

A discrete (state event) variable that is scored when the focal subject reduces its distance to another subject. Approach is based on the approach events detected by Live Mouse Tracker and imported in EthoVision XT. Approach events occur when:

• The speed of the focal subject is greater than the speed of the other subject.
• The distance between the two subjects at the sample k-3, that is, three video frames before the current one k, is greater than the distance at the sample k+3, that is, three video frames after the current one k.

Detection occurs during data acquisition, therefore outside EthoVision XT, and its settings cannot be modified in EthoVision XT.

Contact

A discrete (state event) variable that is scored when the focal subject is in contact with another subject. Contact is based on the contact events detected by Live Mouse Tracker and imported in EthoVision XT. Contact events occur when the distance between the detected contours of the animals gets below a fixed threshold. Detection occurs during data acquisition, therefore outside EthoVision XT, and its settings cannot be modified in EthoVision XT. For more information, please see the Live Mouse Tracker documentation.

NOTE: The dependent variable Body contact under Social behavior in the Analysis profile won't give results with Live Mouse Tracker data, because Body contact can only be based on EthoVision XT's own track data.

Look

Look is a state event variable with possible values Look_up and Look_down.

• Look_down: The subject's head is pointing downward, for example when sniffing the substrate.
• Look_up: The subject's head is pointing upward, for example when rearing at the wall.

Rearing

Rearing is a discrete (state event) variable with two possible values, Rearing and Not rearing. For how it is calculated, see Rear (you can find this variable under Live Mouse Tracker).

The difference between Rearing and Rear is that Rearing includes all rearing events, instead of splitting them into two categories, Rear in contact and Rear alone.

Speed

Speed is imported into EthoVision XT and shown in the Analysis profile under Raw Live Mouse Tracker data, but it is not used as an output variable.

Stop

Stop is based on the stop events detected by Live Mouse Tracker and imported in EthoVision XT. Stop events occur when the speed of the subject gets below a fixed threshold (see Live Mouse Tracker > Stop). Detection of stop events occurs during data acquisition, therefore outside EthoVision XT, and its settings cannot be modified in EthoVision XT.

TIP: To analyze stop events when the subject is in contact with its cage mates, see Stop under Live Mouse Tracker data.

How to Specify Raw Live Mouse Tracker Data

1. Open an Analysis profile and in the Dependent Variables panel, under Raw Live Mouse Tracker data, click the Add button next to a category.
2. Under Calculate statistics for, select the options you require.
3. If the Receivers tab is available, there you can specify which subject the behavior is directed to. Keep all subjects selected for an overview of all the events directed to any individual (A, B, etc.).
4. Complete the procedure to add the variable to the Analysis profile. See Calculate statistics: procedure.

Notes

• You can also use raw Live Mouse Tracker data within JavaScript code to create custom analysis variables. For this purpose, use the GetBehaviorEvent function. See Commands and functions for JavaScript variables.
• Raw Live Mouse Tracker data are not affected by track smoothing. This is because the data are stored during acquisition, and not calculated after import in EthoVision XT. For example, no matter whether you apply Lowess smoothing, the statistics of Contact do not change. On the contrary, Live Mouse Tracker analysis variables are affected by track smoothing, just like any dependent variable in EthoVision XT.

See Also

• Dependent variables for Live Mouse Tracker

Approach Rearing Subject

Definition

A discrete (state event) variable that is scored when the focal subject approaches another subject in rearing posture.

Calculation

This variable combines the variables Social approach and Rear in contact. The state Approach rearing subject is scored when:

• The focal subject is approaching the other, that is, the distance between the two shortens, and that distance is shorter than two times the average body length of the approached subject, calculated throughout the entire track.
• The speed of the focal subject is higher than that of the approached subject.
• The approached subject is in rearing posture, defined as any time that subject's nose point is at least 40 mm higher than its tail base. Rearing in contact occurs within 15 video frames (that is, 0.5 s for video at 30 fps) from the end of the Social approach event.

How to Specify Approach Rearing Subject

1. Open an Analysis profile and in the Dependent Variables panel, under Social, click the Add button next to Approach rearing subject.
2. Complete the procedure to add the variable to the Analysis profile. See Calculate statistics: procedure.

See Also

• Social approach
• Rear
• Live Mouse Tracker

Drink

Definition

A discrete (state event) variable that estimates the time that a subject spent drinking. Drink has two components:

• In the water zone: This marks the time that the focal subject is within a circular zone that includes the water source.
• Drink: The subject is within a smaller circular zone around the water source with a radius being half the radius as above. In addition, the subject is stopped for more than 2 seconds. Therefore, Drink is a more restrictive criterion to estimate the amount of time that the subject spent drinking.

Calculation

Drink is essentially a variable like In zone, because it calculates the time that the subject's center point lies within a zone. In this case the zone is a circle that covers the water tank placed at the bottom-right corner of the apparatus.

• If the distance between the subject's center point and the center of the circle is less than the zone radius, then In the water zone is scored for that sample.
• A smaller zone concentric to the first zone is also considered. If the distance between the subject's center point and the center of the smaller zone is shorter than the zone radius, and if the subject is stopped (see Stop), then Drink is scored for that sample.

How to Specify Drink

1. Open an Analysis profile and in the Dependent Variables panel, under Live Mouse Tracker, click the Add button next to Drink.
2. Under Calculate Statistics for, select In the water zone, Drink or both.
3. Complete the procedure to add the variable to the Analysis profile. See Calculate statistics: procedure.

See Also

• Dependent variables for Live Mouse Tracker

Source: EthoVision XT 19 Help, Noldus Information Technology