Effect of Forced Swimming on the Performance of the “Water Escape Test”

Housing conditions and prior life experiences are known toaffect animal behavior and brain regions that regulate importantneural and physiological functions, such as memory and stress responses. Stressorsof low to moderate intensity can provide an enriched environmentand promote cognitive functions. In contrast, exposures of excessiveseverity and/or duration can lead to maladaptation and distress,altering cognitive functions. Such excessive stressors can thusbe used to model pathological conditions and test diverse therapeuticapproaches. In this study, we addressed whether inescapable exposureof rats to aversive water environment of the “forced swim test”would interfere with their cognitive performance on the subsequent“water escape” test. The data show that a single exposure to a 15-minforced swim session interferes significantly with the ability toescape the water environment. This is manifested by a significantincrease in the latency of diving under the cylinder and a reductionin the proportion of rats capable of completing the test task duringthe initial session. Additionally, there is a lack of developmentin diving skills during repeated sessions at 15-minute intervals.These negative effects can persist for at least 2 weeks. The useof the “forced swim” procedure prior to the “water escape” testmay, therefore, provide a novel experimental approach to modelingstress-induced cognitive dysfunctions and evaluating the effectsof pharmacological agents with potential antidepressant and procognitiveproperties.