A water-reward task assay for evaluating mouse mutualistic cooperative behavior

Abstract

Social cooperation is fundamentally important for group animals but rarely studied with mice because of their natural aggressiveness. In the present work, we induced pairs of mice to develop a mutualistic cooperative behavior in a non-divided chamber. Each mouse was first trained to learn to use a water dispenser by occupying a particular zone served as a switch to the dispenser. Two trained mice were then put into a chamber containing two separate zones jointly controlling two dispensers. We recorded the latency before each co-drinking, the number and cumulated time of co-drinking each day during the test. These parameters served as quantitative measurements of cooperative behavior in mice. The whole procedure includes preparation, training and testing phases, which take 15 days in total. This assay provides detailed procedures and analytical methods for investigators to characterize and quantify the mutualistic cooperative behavior. The use of mice as subjects allows convenient coupling to other behavior assays and is amiable to genetic manipulations for mechanistic study.