Optogenetics in Mood Disorders

Mood disorders pose significant challenges in treatment due to their heterogeneous etiopathological dimensions. This calls for a need to generate a new understanding of neurobiology for translational purposes. The use of optogenetics as an innovative tool has provided novel insights into this neurobiological system. This review was written to compile findings related to depression and bipolar disorder.

Optogenetic research findings presently address the involvement of ventral tegmental area, medial prefrontal cortex (mPFC), dorsal raphe nucleus, hippocampus, nucleus accumbens (NAc), amygdala, and other limbic areas and associated neural are critical for emotional regulation, reward processing, and mood modulation associated with mood disorder. Stimulation of the lateral hypothalamus and circadian rhythm dysregulation are directly and indirectly implicated in bipolar disorder. The combination of antidepressants and repeated optogenetic stimulation of the mPFC-NAc circuit has a potential therapeutic role in treatment-resistant depression.

Optogenetic studies have provided valuable insights regarding the neurobiological mechanisms involved in depression and bipolar disorder. However, there are also implicit limitations in juxtaposing animal behavior to clinical phenotypes of mood disorders. The applicability of optogenetics findings to humans can be enhanced by adopting a framework such as the Research Domain Criteria (RDoC), which encourages a multilevel analysis of neural circuits.