The (Porsolt) forced swim test, also known as the behavioral despair test, is used to test for depression-like behavior in both mice and rats. The test includes placing a rat or mouse inside a cylinder filled with water. The mobility of the animal is measured. Traditionally, ‘floating behavior’ (the animal remains almost immobile and with its head above water) is used as a parameter to analyze ‘hopelessness’ and thus depression-like behavior.
How to get started
With EthoVision XT it is easy to get your experiment up and running. The predefined template for the forced swim test has all the basic settings pre-set, which you can fine-tune to your experiment if desired.
Automatic detection of behaviors
Video tracking allows you to detect some behaviors automatically, such as immobility, indicative of freezing. The three variations of mobility – immobile, mobile, and highly mobile – indicate the three most important behaviors in the forced swim test; floating, swimming, and climbing/ escaping.
There are two ways to detect this with EthoVision XT, which can be used alongside each other. First is by tracking the center point of the animal and determine if it is immobile or not. Of course thresholds can be defined by the user. Second, by activity detection. This method might even give you more robust data as it focusses on changes in the arena from one video frame to the next.
You can program EthoVision XT to automatically start and stop the tracking of your animal, increasing the efficiency of your research. In a forced swim test, mice are often not habituated because some studies show that this influences the test results. Therefore, the first two minutes are seen as the habituation phase of the test and are not included in the results. You can program EthoVision XT to start tracking two minutes after the mouse is detected in the cylinder. You can also program the stopping of tracking; 5 minutes after start, for example.
Translate data into meaningful results
Data interpretation is, of course, a crucial step in your research. In this case, you are probably interested in the latency to floating in a forced swim test, because it is indicative of depressive-like behavior. EthoVision XT provides you with the useful parameters and data selection tools to perform this step. Of course you can export data to software programs, such as for statistical analysis.