Background & Aims

The brain mechanisms of chronic pain are incompletely understood. Novel insights into the brain mechanisms of chronic pain can help define chronic pain biomarkers and identify novel targets for pain treatment. Converging lines of evidence indicate that the dysfunction of intrinsic brain networks (IBNs) plays a crucial role in the pathology of chronic pain [1,2]. In this preregistered study, we use electroencephalography (EEG) data (n > 500) from various research groups across the globe to assess the function of four IBNs that figure most prominently in the pathology of neuropsychiatric disorders and chronic pain [1-3]: the somatomotor, the frontoparietal, the ventral attention, and the default network.

Methods

To assess the function of IBNs, we computed cross-network functional connectivity from resting state EEG data. We related connectivity to pain intensity in patients with different types of chronic pain using both univariate statistical and multivariate machine learning methods. We first analyzed a discovery dataset recorded in our research group (n = 119) and then tested the reliability of findings in six replication datasets (n = 418). As a benchmark, we also assessed the association between pain intensity and other, established features of EEG. Moreover, since age has been shown to robustly covary with many EEG features, we validated our approach by considering age instead of pain intensity as a dependent variable. In exploratory analyses, we expanded the focus and investigated how brain activity and connectivity, beyond the four IBNs of interest, relate to pain intensity.

Results

Univariate analyses in the discovery data set revealed that IBN connectivity correlates with pain intensity at theta and alpha frequencies. While the replicability of these findings was low, an analysis based on the joint data set suggests that theta band connectivity between the somatomotor and salience network most consistently correlates with pain intensity. A machine-learning model linked IBN connectivity to pain intensity in the discovery but not in replication datasets. No evidence was found for an association between benchmark EEG features and pain intensity. Control analyses
confirmed that age is strongly linked to peak alpha frequency and IBN connectivity. Exploratory analyses suggest that associations between pain intensity and brain connectivity, beyond the four IBNs of interest, exist across discovery and replication datasets.

Conclusions

Our multi-dataset study indicates a potential link between chronic pain and IBN connectivity. In line with the literature, univariate analyses suggested that cross- network connectivity in the theta-band, particularly between the somatomotor and the salience network, might be linked to chronic pain severity. Exploratory machine- learning models identified links between pain intensity and brain connectivity beyond the four IBNs of interest. The low replicability of effects is likely due to data heterogeneity. Therefore, future research should aim to minimize the impact of confounding factors and to maximize sample sizes and homogeneity of data acquisition procedures.

References

[1] Kucyi, Aaron, and Karen D. Davis. “The dynamic pain connectome.” Trends in neurosciences 38, no. 2 (2015): 86-95.
[2] Brandl, Felix, Benedikt Weise, Satja Mulej Bratec, Nazia Jassim, Daniel Hoffmann Ayala, Teresa Bertram, Markus Ploner, and Christian Sorg. “Common and specific large-scale brain changes in major depressive disorder, anxiety disorders, and chronic pain: a transdiagnostic multimodal meta-analysis of structural and functional MRI studies.” Neuropsychopharmacology 47, no. 5 (2022): 1071-1080.
[3] Menon, Vinod. “Large-scale brain networks and psychopathology: a unifying triple network model.” Trends in cognitive sciences 15, no. 10 (2011): 483-506.

Presenting Author

Felix S. Bott

Poster Authors

Felix Bott

MSc

Technical University of Munich

Lead Author

Özgün Turgut

M.Sc.

Technical University of Munich

Lead Author

Paul Theo Zebhauser

University Hospital of the Klinikum rechts der Isar, Technical University Munich

Lead Author

Vanessa D. Hohn

PhD

Lead Author

Henrik Heitmann

MD

Lead Author

Elisabeth S. May

Dr.

Lead Author

Laura Tiemann

Dr.

Lead Author

Cristina Gil Àvila

PhD

Lead Author

Melissa A. Day

PhD

Faculty of Health and Behavioural Sciences. University of Queensland (Australia).

Lead Author

Divya Adhia

PhD

Dunedin School of Medicine, University of Otago, New Zealand

Lead Author

Yoni Ashar

Univ. Colorado Anschutz

Lead Author

Tor Wager

Dartmouth College

Lead Author

Yelena Granovsky

Rambam Health Care Campus

Lead Author

David Yarnitsky

PhD

Rambam Health Care Campus

Lead Author

Mark P. Jensen

PhD

University of Washington. Seattle, WA, USA

Lead Author

Joachim Gross

PhD

Lead Author

Markus Ploner

Technische Universitaet Munchen

Lead Author

Topics

  • Pain Imaging