Using light to establish habits in laboratory mice

Abstract Background and aims Perseverative behaviours are commonly assessed using operant paradigms in which rodents work for drugs or food under physiological deprivation, limiting translational relevance to some behavioural addictions. Here we validated an operant paradigm in which the acquired behaviour is driven neither by physiological needs nor hedonic responses. Methods Mice were trained to lever-press for green light. Exp.1 used a within-subjects design to examine lever discrimination and whether responding could be “ satiated ” by light preexposure. Exp.2 examined instrumental contingency using a between-subjects design, with light delivery equated between contingent and non-contingent groups. Exp.3 replaced green light with dim red light producing less retinal photoreceptor excitation but comparable heat to assess non-photic cues. Exp.4 examined whether green light could affect food seeking different motivational states. Results In Exp.1, green light supported lever discrimination. Among high responders, the satiation effect was modest (