Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
Cognitive Psychology Unit, Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, 2300 RC Leiden, The Netherlands.
eNeuro. 2021 Feb 11;8(1). doi: 10.1523/ENEURO.0230-20.2020. Print 2021 Jan-Feb.
Powerful neural measurement and perturbation tools have positioned mice as an ideal species for probing the neural circuit mechanisms of cognition. Crucial to this success is the ability to motivate animals to perform specific behaviors. One successful strategy is to restrict their water intake, rewarding them with water during a behavioral task. However, water restriction requires rigorous monitoring of animals' health and hydration status and can be challenging for some mice. 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). 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 here extend this approach to mice and confirm its robustness across multiple laboratories. Mice reduced their intake of CA water while maintaining healthy weights. 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. When free CA water was used instead of water restriction only on weekends, learning and decision-making behavior were unaffected. CA water is thus a promising alternative to water restriction, allowing animals more control over their water intake without interfering with behavioral performance.
强大的神经测量和干扰工具使小鼠成为探究认知神经回路机制的理想物种。成功的关键是能够激励动物执行特定的行为。一种成功的策略是限制它们的饮水量，在行为任务期间用水分给它们奖励。然而，水限制需要严格监测动物的健康和水合状态，并且对一些老鼠来说可能具有挑战性。我们提出了一种替代方法，允许老鼠更自由地控制自己的饮水量：通过少量柠檬酸（CA）使水变酸，让它们在自己的笼子里自由饮水。在之前的一项研究中，自由饮用 CA 水的大鼠很乐意通过饮水来获得奖励，尽管完成的试验比水限制组少（Reinagel，2018）。在这里，我们将这种方法扩展到了小鼠身上，并在多个实验室中证实了其稳健性。小鼠减少了 CA 水的摄入量，同时保持了健康的体重。连续的笼子里自由饮用 CA 水只是略微影响了它们进行决策任务的意愿，在这个任务中，它们会因摄入加糖的水而获得奖励。当只在周末用 CA 水代替水限制时，学习和决策行为不受影响。因此，CA 水是水限制的一种有前途的替代方法，它允许动物更自由地控制自己的饮水量，而不会干扰行为表现。
