Distinct Insular Functional Connectivity Changes Related to Mood and Fatigue Improvements in Major Depressive Disorder Following Tai Chi Training: A Pilot Study

Objective: Tai Chi (TC), a contemplative practice combining slow movements and deep breathing, has been shown to be clinically effective in alleviating depressive symptoms. Feelings of fatigue, or low vitality, often accompany Major Depressive Disorder (MDD) though they are commonly overlooked and not well understood neurologically. By using resting state functional connectivity (rs-FC) using the insula as the seed, this study examines the relationship between mood and vitality symptoms in MDD and how they are impacted by TC training. Methods: Patients (N=16) with MDD participated in a 10-week TC intervention. Self-report scores of vitality (using SF-36 scale) and depressed mood (using Beck Depression Inventory) as well as rs-fMRI were collected pre- and post-intervention. A seed-to-voxel approach was used to test whether changes in insular rs-FC were related to therapeutic improvement in MDD-related symptoms resulting from TC practice. Results: We found decreased self-reported depressed mood and increased vitality following the TC intervention. Furthermore, decreases in depressed mood were associated with increased functional connectivity between the right anterior insula (AI) and occipital pole as well as between the left AI and left anterior cingulate cortex (cluster-corrected p < 0.05). Increased vitality was associated with increased fc between the right posterior insula (PI) and regions associated with sensorimotor processes (cluster-corrected p < 0.05). Conclusion: These results provide support for differential changes in insula connectivity as neural correlates of symptom improvement in MDD. Acronyms: TC=Tai Chi; MDD=Major Depressive Disorder; rs-FC=resting-state Functional Connectivity; rs-fMRI=resting-state functional magnetic resonance imaging; AI=anterior insula; PI=posterior insula