Forced Swim

Typically used to conduct the Porsolt forced swim test, a commonly used screening method for assessing antidepressant activity. Porsolt pioneered the use of rodents in depressive models, and the efficacy of anti-depressive compounds in them.

Rodents are put into the cylindrical container filled with water. By forcing a mouse to swim in this aversive/restrictive space it will actively struggle for a few minutes, but eventually stop moving and become noticeably weary, making only small movements to keep their head above water.

Porsolt (et al) called this state of hopelessness “behavioral despair” and compared it to a human experiencing depressive symptoms. It was noted that anti-depressants appeared to increase the latency to this immobile state, and that the time exhibiting immobile behaviors decreases while active behavior increases.

The immobility time is generally measured for a short time, e.g. 5 or 10 min, and can be measured by manual observation with a stopwatch or with a video analyzing software .

The video images are generally best handled as binary (monochrome) images so the rodent is detected as a silhouette. Our backlit chamber increases the contrast for easier analysis.