A Head-Fixed Behavioral Paradigm Linking M2 Neuronal Activity to Reversal Decision Performance

Background/Objectives: To enhance experimental flexibility and accommodate high-precision neural recording techniques, psychological testing tasks have been adapted for head-fixed rodent models. However, many early head-fixed mouse behavioral paradigms were procedurally complex to train, making it difficult to capture spontaneous decision-making processes in a less stressful environment. The secondary motor cortex (M2) has been implicated in adaptive behaviors in rodents, including decision-related processes in complex tasks. Methods: In this study, we developed a novel decision-making paradigm for head-fixed mice, which simulates natural decision reactions by allowing mice to freely explore and make choices within a suspended home cage, combined with reward reversal contingencies. This approach provided a platform for investigating the role of M2 in decision-making behavior. Results: By fiber photometry and chemogenetic experiments, we demonstrated that neural activity of the M2 in male mice was associated with behavioral performance, and chemogenetic inhibition of M2 neurons impaired behavioral flexibility during reversal learning. Conclusions: These results indicate that this paradigm provides a robust experimental platform for investigating the neural mechanisms of M2-mediated decision-making and implicate M2 activity in adaptive decision-making.