A novel mouse-friendly cognitive task suitable for use in aging studies

Tests of cognition in mice frequently employ deprivations or aversive stimuli to motivate learning. Such manipulations may confound interpretation of differences in performance. Concerns arising from the potential confounding are accentuated when the object of the experiment is to compare cognitive function of young and old animals because aging alters many processes that affect maze performance. To assuage some of these concerns, we tested the potential of a novel reward procedure to motivate maze learning. Food-and water-satiated mice of two genetically heterogeneous groups that gained access to their home cage after reaching the goal box of a Lashley III maze attained the acquisition criterion as quickly as did mice motivated by hunger and given food reward. We suggest that "return to home cage" is a useful reinforcer in tests of cognition. This reward procedure is unusual in that it offers an important animal-friendly alternative to the usual ways of motivating cognitive performance, is economical of experimenter time, and may avoid the potentially confounding effects of physiological deprivations and aversive stimuli on maze performance of aged mice.