Knowledge Base

Acquiring Data

Protocol

Basic Protocol (Rats)

Pre-test trial (day 1, before drug administration): The animal is placed in the cylinder for 15 minutes. No scoring of immobility is performed during the first session. This session is needed to acclimatize the rats to the experimental situation and to induce a stable, high level of immobility during the test session.

Test (day 2): After drug administration, the animal is placed in the cylinder for 5 minutes. Score the duration of immobility by summing the time spent immobile; score as immobile minor movements strictly necessary to maintain the animal's head above water.

Alternate Protocol (Mice)

The mouse is placed in the cylinder. The trial lasts 6 minutes. Measure the latency to immobility from the start of the trial and the duration of immobility for the last 4 minutes.

See Castagné et al. (2011). Current Protocols in Neuroscience 8.10A.1-8.10A.14.

Score Behaviors Manually

If you want to score the subject's behavior manually, define them first under Manual Scoring Settings. After you have started the trial, watch the subjects in the video and in the Manual Scoring tab at the bottom of the screen, click the button to the category that applies. As soon as the behavior of the subject changes, click the button for the corresponding category.

Important: If you do tracking from video, make sure you de-select DDS in the Playback Control window.

You can also score behaviors after tracking. See Acquire Data > Score Behaviors Manually in the EthoVision XT Help.

Determining Mobility Thresholds

To find the optimal Highly mobile and Immobile thresholds, you can run a few test trials and check in the Analysis Results and Scoring pane (Dependent Variables tab) the values for Mobility state in relation to the behavior the animal displays. If the Mobility states do not correspond to the behavior of the animal, in the Analysis Results and Scoring pane:

1. Click Dependent Variables.
2. Click the button under Mobility state.
3. Adjust the Highly mobile threshold and Immobile threshold.

For example, if the animal is struggling, its corresponding Mobility state is Highly mobile. If the current Mobility score is Mobile or Immobile, you probably need to reduce the Highly mobile threshold.

Note that you can also adjust the Mobility thresholds after acquisition. In the Analysis profile, add the Mobility state variable and visualize the data.

If you do not see the Mobility state variable on your screen, click Show/Hide on the toolbar and select Show Dependent Variables, then Mobility state and Mobility.

Determining Activity Thresholds

In the same way as you defined thresholds for Mobility state, you can define thresholds for Activity state. Use Activity state if Mobility state does not give satisfying results, for instance when detecting thrashing of the animal's limbs which may not be detected properly by Mobility.

Note that when you work with multiple cylinders in the same video image, Activity state gives good results when the size of the arena is the same for all cylinders. In the Arena Settings, adjust the contour of the arenas to make them similar.

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