Increased Brain Gray Matter in the Primary Somatosensory Cortex is Associated with Increased Pain and Mood Disturbance in Patients with Interstitial Cystitis/Painful Bladder Syndrome

Abstract

Purpose Interstitial cystitis (IC) is a highly prevalent pain condition, estimated to affect 3-6% of women in the United States. Emerging data suggests there are central neurobiological components to the etiology of this disease. Here we report the first brain structural imaging findings from the Multidisciplinary Approach to Pelvic Pain (MAPP) network, with data on over 300 participants. Materials and Methods We used Voxel-Based Morphometry (VBM) to determine whether human patients with chronic IC display changes in brain morphology as compared to healthy controls (HCs). 33 female IC patients without comorbidities and 33 age- and sex-matched controls, taken from the larger sample, underwent structural magnetic resonance imaging at 5 different MAPP sites across the United States. Results When compared to controls, females with IC displayed significant increased gray matter (GM) volume in several regions of the brain including the right primary somatosensory cortex (S1), the superior parietal lobule bilaterally, and the right supplementary motor area. GM volume in the right S1 was associated with greater pain, mood (anxiety), and urological symptoms. We explored these correlations in a linear regression model and found independent effects of these three measures on S1 GM volume: clinical pain (McGill pain sensory total), a measure of “urgency,” and anxiety (HADS). Conclusions These data support the notion that changes in somatosensory GM may play an important role in pain sensitivity as well as affective and sensory aspects of IC. Further studies are needed to confirm the generalizability of these findings to other pain conditions.

Preliminary structural MRI based brain classification of chronic pelvic pain: A MAPP network study

“…Additionally, through our use of the SVM algorithm, we identified several brain regions of positive contributory weights, suggesting greater GM density in these regions in CPP. Some of these regions were in agreement with regions identified in a conventional VBM analysis also conducted through the MAPP Research Network [25]. Compared to the conventional univariate analysis, our SVM approach appeared to be more sensitive to identifying additional regions of morphological differences between CPP and healthy controls.…”

“…Increased GM density in S1 was observed in another chronic visceral pain syndrome (IBS), both in terms of GM volume [28] and cortical thickness [24]. A region we identified within the primary somatosensory cortex (S1) was highly similar in location to a VBM study of females with CPP also collected through the MAPP Research Network [25]. Somatotopically, two regions that we observed in S1 were within a region activated during electrical stimulation of the human clitoris [33].…”

Brain White Matter Abnormalities in Female Interstitial Cystitis/Bladder Pain Syndrome: A MAPP Network Neuroimaging Study

“…Collectively, these microstructural abnormalities may influence the flow of neural information throughout the brain, thereby mediating brain reorganization previously observed in male pelvic pain 10 . This hypothesis is supported by IC/BPS-related shifts in oscillatory patterns of neuronal activity (function) and increased grey matter density (structure) in regions that modulate visceral and somatosensation and potentially pelvic floor motor function in women with IC/BPS 15, 16 . These anatomical abnormalities are strongly suggestive of neuropathological processes underlying IC/BPS.…”

Multivariate morphological brain signatures predict patients with chronic abdominal pain from healthy control subjects

“…Compared to the previously used parcellation based on the LBP40 atlas, the parcellation based on the Destrieux atlas used here provided greater resolution to identify more specific regions within the sensorimotor, cingulate, insular, and prefrontal cortices. Increased volume and cortical thickness in the somatosensory and motor regions have been reported in other chronic pain conditions including interstitial cystitis/painful bladder syndrome [30], trigeminal neuralgia [14], migraine [12] and temporomandibular disorders [53; 54]. Cortical thickening in primary somato-sensensory regions and posterior midcingulate cortex in healthy subjects has been associated with greater sensitivity to experimental temperature and pain stimuli [20].…”