Assessment of Mouse Judgment Bias through an Olfactory Digging Task

This is the first ever mouse judgment bias task to be validated as sensitive to changes in affective state, in other words, mood or emotion. It can be used to investigate the effects of any variable on mouse affect. This protocol uses an ethological design, making it easy for mice to learn, and it's also welfare friendly, since the task avoids the use of punishment or negative reinforcement.

This task can assess the impact of husbandry or experimental procedures on mouse affective states, making it valuable across diverse fields, like animal welfare research or modeling human affective disorders. Assuming researchers are already comfortable with non-aversive handling methods, our main advice is to use pilots before training to identify appropriate odor mixtures, in other words, the ones that mice treat as ambiguous. This behavioral test is a scent-based go-go digging task in which a mouse must dig for high-or low-value food rewards.