Citric Acid water as an alternative to water scheduling in behaving mice

Powerful neural measurement and perturbation tools have positioned mice as an ideal model 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 schedule their water intake, rewarding them with water during a behavioral task. However, water scheduling requires rigorous monitoring of animal9s health and hydration status, and can be challenging for some animals. Here, we present an alternative that allows mice more control over their water intake: free home- cage access to water to which a small amount of Citric Acid (CA) has been added. CA makes water taste slightly sour, but still palatable. Mice reduce their intake of CA water while still maintaining a healthy weight. Home-cage access to CA water has only subtle impacts on their willingness to perform a decision-making task, in which they are rewarded with sweetened water. CA water is thus a promising alternative that allows animals more control over their water intake without interference to behavioral performance.