Calcium imaging: Unraveling the neurobiological mechanisms of depression across cellular and circuit dimensions.

Calcium imaging has emerged as a pivotal technique for monitoring neuronal and glial activity, gaining widespread recognition in neuroscience research. This method primarily utilizes genetically encoded calcium indicators (GECIs) or synthetic fluorescent dyes to detect physiologically relevant calcium dynamics. Despite being one of the most prevalent mental disorders, depression's pathogenesis remains poorly understood. Calcium imaging serves as a powerful tool to identify depression-related cell types and neural circuits. This review systematically summarizes the evolution of calcium indicators and their integration with behavioral paradigms, electrophysiology, optogenetics, and chemogenetics to elucidate cellular and circuit mechanisms underlying depression. In addition, calcium imaging in depression and other disease comorbidities is also discussed. These synthesized findings establish a framework for developing precision-targeted antidepressant interventions.