Negative transfer effects between reference memory and working memory training in the water maze in C57BL/6 mice

• Published in: Behavioural brain research Vol. 339; pp. 286 - 296
• Main Authors: Serrano Sponton, Lucas Ezequiel, Soria, Gonzalo Jose, Dubroqua, Sylvain, Singer, Philipp, Feldon, Joram, Gargiulo, Pascual A., Yee, Benjamin K.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 26.02.2018
• Subjects: Animals; Attention - physiology; Behavior, Animal; Male; Maze Learning - physiology; Memory, Short-Term - physiology; Mice, Inbred C57BL; Mouse; Spatial Behavior - physiology; Spatial learning; Transfer (Psychology) - physiology; Transfer effect; Water maze; Mouse; Transfer effect; Spatial learning; Water maze
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2017.10.033

•Reference and working water maze tests involve conflicting cognitive demands.•Mice being trained on one test showed robust impairment in the other test.•The negative transfer is robust, bidirectional, and of medium-to-large effect size.•This demonstration bears implications on cognitive phenotyping of mutant mice.•Sequential use of the two tests in the same animals warrants extra caution. The water maze is one of the most widely employed spatial learning paradigms in the cognitive profiling of genetically modified mice. Oftentimes, tests of reference memory (RM) and working memory (WM) in the water maze are sequentially evaluated in the same animals. However, critical difference in the rules governing efficient escape from the water between WM and RM tests is expected to promote the adoption of incompatible mnemonic or navigational strategies. Hence, performance in a given test is likely poorer if it follows the other test instead of being conducted first. Yet, the presence of such negative transfer effects (or proactive interference) between WM and RM training in the water maze is often overlooked in the literature. To gauge whether this constitutes a serious concern, the present study determined empirically the magnitude, persistence, and directionality of the transfer effect in wild-type C57BL/6 mice. We contrasted the order of tests between two cohorts of mice. Performance between the two cohorts in the WM and RM tests were then separately compared. We showed that prior training of either test significantly reduced performance in the subsequent one. The statistical effect sizes in both directions were moderate to large. Although extended training could overcome the deficit, it could re-emerge later albeit in a more transient fashion. Whenever RM and WM water maze tests are conducted sequentially in the same animals – regardless of the test order, extra caution is necessary when interpreting the outcomes in the second test. Counterbalancing test orders between animals is recommended.