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

SERRANO SPONTON, LUCAS EZEQUIEL; SORIA, GONZALO JOSE; DUBROQUA, SYLVAIN; SINGER, PHILIPP; FELDON, JORAM; GARGIULO, PASCUAL A.; YEE, BENJAMIN K.

BEHAVIOURAL BRAIN RESEARCH

ELSEVIER SCIENCE BV

Año: 2017

0166-4328

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 aserious 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 reemerge 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 theoutcomes in the second test. Counterbalancing test orders between animals is recommended.