Background/Purpose: Studies found that individuals with pain exhibit altered thalamocortical rhythm, abnormal function, and structural connectivity within the network. Effective treatment may relieve pain by modulating the thalamocortical circuits. We examine how remote Tai Chi mind-body exercise modulates the static and dynamic resting state functional connectivity (rsFC) of thalamus subregions associated with movement, sensory and limbic systems.

Methods: Patients ≥ 50 years of age who met ACR criteria for symptomatic KOA were randomized to either a Tai Chi or Wellness Education and attended 12 weeks of biweekly remote sessions. The clinical outcomes included WOMAC, Anxiety and Depression, Self-efficacy and quality of life. Resting-state Functional magnetic resonance imaging (fMRI, using simultaneously multi-slice sequences) and high-resolution structure MRI scans were applied with a 3.0T Siemens scanner at baseline and after intervention. We applied theCONN toolbox for seed-based static and dynamic rsFC analysis. Three thalamus subregions (motor thalamus subregion, ventral posterolateral thalamus and mediodorsal thalamus) were used as seeds based on parcellation of the thalamic nuclei of AAL3. A threshold of p < 0.005 voxel-wise and p < 0.05 False Discovery Rate corrected at cluster level was applied for whole-brain analysis. Small volume correction was applied for pre-defined regions of interest (limbic system and prefrontal cortex).

Results: Thirty-four patients were randomized and 31 completed pre- and post-MRI scans. Mean age was 66 years, 65% female. At 12 weeks, compared to education, a significantly greater improvement in WOMAC pain score was found in the Tai Chi group (p < 0.05). No significant differences between groups were found for other clinical outcomes. Static rsFC analysis showed that compared to Wellness education, remote Tai Chi exercise increased 1) motor thalamus subregion static rsFC at the right cerebellum (lateral hemisphere); 2) ventral posterolateral thalamusstatic rsFC at the right cerebellum (medial and lateral hemisphere); 3) mediodorsal thalamus static rsFC at the bilateral cerebellum (medial and lateral hemisphere). TaiChi decreased 1) motor thalamus subregion static rsFC at the bilateral dorsal anterior cingulate cortex (dACC) and right amygdala/hippocampus; 2) ventral posterolateral thalamus static rsFC at the right lateral and orbital prefrontal cortex, bilateral dACC/mid-cingulate cortex, and right hippocampus; 3) mediodorsal thalamus static rsFC at bilateral temporal gyrus/uncus/amygdala/hippocampus. Dynamic rsFC analysis showed that compared to Wellness education, remote Tai Chi decreased 1) motor thalamus subregion dynamic rsFC at the left rACC/medial prefrontal cortex (mPFC), and bilateral cerebellum; 2) ventral posterolateral thalamus dynamic rsFC at the bilateral rACC/mPFC, primary motor and premotor cortex and middle temporal gyrus. No significant findings when using the mediodorsal thalamus as a seed.

Conclusion: Our results suggest that remote Tai Chi can modulate the functional connections between the thalamus-cerebellum and thalamus-limbic systems in individuals with KOA, and can reduce theconnectivityvariability betweenthese regions.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/thalamocortical-mechanisms-of-a-remote-mind-body-intervention-for-knee-osteoarthritis-pain/