Leveraging Fiber Photometry to Decipher Neural Circuits Underlying Anxiety in Mice

Anxiety disorders rank among the most prevalent mental health conditions worldwide, significantly affecting patients' lives. They are frequently comorbid with other psychiatric disorders, often exacerbating their severity. Current pharmacological treatments; selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines, remain limited in efficacy and are associated with undesirable side effects, underscoring the urgent need for alternative therapeutic approaches. However, progress in developing new treatments has been hindered by an incomplete understanding of the neural mechanisms underlying these disorders. Bridging this knowledge gap requires advanced research tools capable of providing deeper insight into the neural circuits involved in anxiety. Fiber photometry (FP) has emerged as a powerful and cost-effective technique for measuring neural activity in freely moving animal models. By enabling real-time monitoring of calcium dynamics in specific neural populations within defined brain regions, this method offers invaluable insights into both normal physiological processes and pathological states. In this review, we first present an accessible introduction to FP, detailing its apparatus, procedures, and key advantages and limitations. We then conducted a comprehensive analysis of 39 studies indexed in PubMed that have employed FP to investigate neural circuits implicated in anxiety. Our review reveals the techniques' significant contributions across different research domains, including physiological (33%), pathological (53%), and dual-purpose studies (13%). Beyond summarizing its utility, our goal is to make FP more accessible to researchers. By providing a foundational guide for its integration into future scientific projects, we aim to facilitate advances in anxiety research and contribute to the development of novel therapeutic strategies.