While long thought to be beyond the capacities of the mouse ( Abbott, 2010), mice are now routinely trained to perform abstract sensory, navigational and decision-making tasks ( Carandini and Churchland, 2013 Guo et al., 2014 Goltstein et al., 2018). The mouse is an indispensable species for systems neuroscience, thanks to a rich set of available tools to record and manipulate brain structure and function, combined with the knowledge of teaching mice specific behavioral tasks. CA water is thus a promising alternative to water restriction, allowing animals more control over their water intake without interfering with behavioral performance.
When free CA water was used instead of water restriction only on weekends, learning and decision-making behavior were unaffected. Continuous home-cage access to CA water only subtly impacted their willingness to perform a decision-making task, in which they were rewarded with sweetened water. Mice reduced their intake of CA water while maintaining healthy weights. We here extend this approach to mice and confirm its robustness across multiple laboratories. In a previous study, rats with free access to CA water readily performed a behavioral task for water rewards, although completing fewer trials than under water restriction ( Reinagel, 2018).
We present an alternative that allows mice more control over their water intake: free home-cage access to water, made slightly sour by a small amount of citric acid (CA). However, water restriction requires rigorous monitoring of animals’ health and hydration status and can be challenging for some mice. One successful strategy is to restrict their water intake, rewarding them with water during a behavioral task. Crucial to this success is the ability to motivate animals to perform specific behaviors.
Powerful neural measurement and perturbation tools have positioned mice as an ideal species for probing the neural circuit mechanisms of cognition.