Background & Aims

The pathophysiology underlying chronic temporomandibular disorder (TMD) pain is poorly understood; however current consensus on its brain mechanisms includes those associated with central sensitization leading to pain amplification.[1-3] Brain connectivity is one way to assess anatomical and functional characteristics that can partially explain human behavior, including pain perception. Multimodal magnetic resonance imaging (MRI) allows assessment of brain connectivity in humans using tractography from diffusion MRI (dMRI) and weighted dual regression from functional MRI (fMRI) to determine anatomical (AC) and functional connectivity (FC), respectively. Our goal was to compare the anatomical and functional brain connectivity of chronic TMD pain cases relative to pain-free controls.

Methods

52 female participants were divided as controls (n=17) and TMD cases (n=35) with pain >6 months who met criteria[4] for jaw muscle pain (myalgia), with or without concurrent jaw joint pain and/or headache. Multimodal brain MRI was acquired per the Human Connectome Project (HCP) protocol:[5] 4 dMRI, 2 resting-state fMRI, 2 stimulus-evoked fMRI (painful dentoalveolar pressure). MRI data was preprocessed using the HCP pipelines,[6] including global noise removal.[7] AC was calculated for 42 white matter (WM) tracts using FSL’s xtract_blueprint[8] to generate individual cortical/subcortical connectivity profiles, while FC was determined using weighted dual regression from HCP pipelines[7] to generate individual FC spatial maps from group-level maps. Data were parcellated into 441 regions of interest (ROIs) including cortical and subcortical parcels. AC and FC parcellated data were used for group analyses using permutation tests[9] with multiple comparisons correction[10] (alpha=0.05).

Results

Relative to controls, AC was reduced for TMD cases in ROIs associated with the right corticospinal (3 ROIs: 0.035

Conclusions

These results suggest that female chronic TMD pain cases present with abnormal brain connectivity in diverse brain structures, including those relevant to somatomotor functions. Importantly, the brain network associated with the somatotopical representation of the face over the somatomotor cortices showed reduced FC during painful dentoalveolar pressure stimulation in the right nucleus accumbens, while this was not true for FC during rest. Further investigation of altered brain connectivity is warranted to understand their role in chronic TMD pain pathophysiology.

References

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Presenting Author

Estephan Moana-Filho

Poster Authors

Estephan Moana-Filho

DDS, MS, PhD

University of Minnesota School of Dentistry

Lead Author

Christophe Lenglet

PhD

University of Minnesota Center for Magnetic Resonance Research (Department of Radiology)

Lead Author

David Bereiter

PhD

University of Minnesota School of Dentistry

Lead Author

Lynn Eberly

PhD

University of Minnesota School of Public Health

Lead Author

Topics

  • Specific Pain Conditions/Pain in Specific Populations: Orofacial Pain