Network properties and regional brain morphology of the insular cortex correlate with individual pain thresholds

• Main Authors: Bingel, U. (Author), Neumann, L. (Author), Schmidt-Wilcke, T. (Author), Spisak, T. (Author), Witte, V. (Author), Wulms, N. (Author), Zunhammer, M. (Author)
• Format: Article
• Language: English
• Published: John Wiley and Sons Inc 2021
• Subjects: adult; Adult; anatomy and histology; article; biological variation; Biological Variation, Individual; brain region; cluster coefficient; connectome; Connectome; diagnostic imaging; functional connectivity; functional magnetic resonance imaging; graph theory; gray matter volume; human; Humans; insula; Insular Cortex; Magnetic Resonance Imaging; nuclear magnetic resonance imaging; pain; pain threshold; Pain Threshold; parietal operculum; physiology; plant seed; postcentral gyrus; primary somatosensory cortex; resting-state fMRI; secondary somatosensory cortex; structure activity relation; theoretical study; voxel based morphometry; voxel-based morphometry; young adult; Young Adult
• Online Access: View Fulltext in Publisher

 Pain thresholds vary considerably across individuals and are influenced by a number of behavioral, genetic and neurobiological factors. However, the neurobiological underpinnings that account for individual differences remain to be fully elucidated. In this study, we used voxel-based morphometry (VBM) and graph theory, specifically the local clustering coefficient (CC) based on resting-state connectivity, to identify brain regions, where regional gray matter volume and network properties predicted individual pain thresholds. As a main finding, we identified a cluster in the left posterior insular cortex (IC) reaching into the left parietal operculum, including the secondary somatosensory cortex, where both regional gray matter volume and the local CC correlated with individual pain thresholds. We also performed a resting-state functional connectivity analysis using the left posterior IC as seed region, demonstrating that connectivity to the pre- as well as postcentral gyrus bilaterally; that is, to the motor and primary sensory cortices were correlated with individual pain thresholds. To our knowledge, this is the first study that applied VBM in combination with voxel-based graph theory in the context of pain thresholds. The co-location of the VBM and the local CC cluster provide first evidence that both structure and function map to the same brain region while being correlated with the same behavioral measure; that is, pain thresholds. The study highlights the importance of the posterior IC, not only for pain perception in general, but also for the determination of individual pain thresholds. © 2021 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.