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Ikarashi H, Otsuru N, Gomez-Tames J, Hirata A, Nagasaka K, Miyaguchi S, Sakurai N, Ohno K, Kodama N, Onishi H. Modulation of pain perception through transcranial alternating current stimulation and its nonlinear relationship with the simulated electric field magnitude. Eur J Pain 2024; 28:1018-1028. [PMID: 38318653 DOI: 10.1002/ejp.2249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 01/18/2024] [Accepted: 01/21/2024] [Indexed: 02/07/2024]
Abstract
BACKGROUND Oscillatory activities observed in multiple regions are closely associated with the experience of pain. Specifically, oscillatory activities within the theta- and beta-frequency bands, observed in the left dorsolateral prefrontal cortex (DLPFC), have been implicated in pain perception among healthy individuals and those with chronic pain. However, their physiological significance remains unclear. METHODS We explored the modulation of pain perception in healthy individuals by theta- and beta-band transcranial alternating current stimulation (tACS) over the left DLPFC and examined the relationship between the modulation effect and magnitude of the electric field elicited by tACS in the left DLPFC using computational simulation. RESULTS Our findings revealed that both theta- and beta-tACS increased the heat pain threshold during and after stimulation. Notably, the simulated electric field magnitude in the left DLPFC exhibited an inverted U-shaped relationship with the pain modulation effect for theta-tACS. CONCLUSIONS Our study findings suggested that there would be an optimal electric field strength to produce a high analgesic effect for theta-tACS. SIGNIFICANCE The application of theta- and beta-tACS interventions targeting the left DLPFC might facilitate the treatment of chronic pain. Furthermore, the attainment of effective pain modulation via theta-tACS over the DLPFC warrants the use of optimal stimulus intensity.
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Affiliation(s)
- H Ikarashi
- Graduate School, Niigata University of Health and Welfare, Niigata, Japan
| | - N Otsuru
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - J Gomez-Tames
- Department of Electromechanical Engineering, Nagoya Institute of Technology, Nagoya, Aichi, Japan
- Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya, Aichi, Japan
| | - A Hirata
- Department of Electromechanical Engineering, Nagoya Institute of Technology, Nagoya, Aichi, Japan
- Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya, Aichi, Japan
| | - K Nagasaka
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - S Miyaguchi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - N Sakurai
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - K Ohno
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - N Kodama
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
| | - H Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan
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2
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Kitano K, O'Hashi K, Fujita S, Kobayashi M. Reduction in calcium responses to whisker stimulation in the primary somatosensory and motor cortices of the model mouse with trigeminal neuropathic pain. J Oral Biosci 2024:S1349-0079(24)00140-3. [PMID: 38880250 DOI: 10.1016/j.job.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/13/2024] [Accepted: 06/14/2024] [Indexed: 06/18/2024]
Abstract
OBJECTIVE Chronic constriction injury (CCI) of the infraorbital nerve induces neuropathic pain, such as allodynia and hyperalgesia, in the orofacial area. However, the changes in the local circuits of the central nervous system following CCI remain unclear. This study aimed to identify the changes following CCI in Thy1-GCaMP6s transgenic mice. METHODS Neural activity in the primary somatosensory cortex (S1) and motor cortex (M1) following whisker stimulation was assessed using in vivo Ca2+ imaging. CCI-induced changes in responses were analyzed. RESULTS Before CCI, whisker stimulation induced a greater Ca2+ response in the contralateral S1 than in the ipsilateral S1 and contralateral M1. The peak Ca2+ response amplitude in the bilateral S1 and contralateral M1 decreased two days after CCI compared to before CCI. Decreased Ca2+ response amplitude in these regions was observed until four days after CCI. Seven days after CCI, the Ca2+ response amplitude in the contralateral S1 decreased, whereas that in the ipsilateral S1 and contralateral M1 recovered to control levels. CONCLUSION These results suggest that neural activity in regions receiving excitatory inputs via corticocortical pathways recovers earlier than in regions receiving thalamocortical inputs. (185/250 words).
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Affiliation(s)
- Kouhei Kitano
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Kazunori O'Hashi
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Satoshi Fujita
- Department of Biology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Masayuki Kobayashi
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; Division of Oral and Craniomaxillofacial Research, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
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3
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Emvalomenos GM, Kang JWM, Jupp B, Mychasiuk R, Keay KA, Henderson LA. Recent developments and challenges in positron emission tomography imaging of gliosis in chronic neuropathic pain. Pain 2024:00006396-990000000-00597. [PMID: 38713812 DOI: 10.1097/j.pain.0000000000003247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/05/2024] [Indexed: 05/09/2024]
Abstract
ABSTRACT Understanding the mechanisms that underpin the transition from acute to chronic pain is critical for the development of more effective and targeted treatments. There is growing interest in the contribution of glial cells to this process, with cross-sectional preclinical studies demonstrating specific changes in these cell types capturing targeted timepoints from the acute phase and the chronic phase. In vivo longitudinal assessment of the development and evolution of these changes in experimental animals and humans has presented a significant challenge. Recent technological advances in preclinical and clinical positron emission tomography, including the development of specific radiotracers for gliosis, offer great promise for the field. These advances now permit tracking of glial changes over time and provide the ability to relate these changes to pain-relevant symptomology, comorbid psychiatric conditions, and treatment outcomes at both a group and an individual level. In this article, we summarize evidence for gliosis in the transition from acute to chronic pain and provide an overview of the specific radiotracers available to measure this process, highlighting their potential, particularly when combined with ex vivo/in vitro techniques, to understand the pathophysiology of chronic neuropathic pain. These complementary investigations can be used to bridge the existing gap in the field concerning the contribution of gliosis to neuropathic pain and identify potential targets for interventions.
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Affiliation(s)
- Gaelle M Emvalomenos
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - James W M Kang
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Bianca Jupp
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - Kevin A Keay
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Luke A Henderson
- School of Medical Sciences [Neuroscience], and the Brain and Mind Centre, The University of Sydney, Sydney, Australia
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4
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Yin Y, He S, He N, Zhang W, Luo L, Chen L, Liu T, Tian M, Xu J, Chen S, Li F. Brain alterations in sensorimotor and emotional regions associated with temporomandibular disorders. Oral Dis 2024; 30:1367-1378. [PMID: 36516329 DOI: 10.1111/odi.14466] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 11/21/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVES Temporomandibular disorders (TMD) are characterized by sensorimotor and psychological dysfunction, with evidence revealing the implication of a dysfunctional central nervous system. Previous magnetic resonance imaging (MRI) studies have reported brain alterations in TMD, but most studies focused on either structure or function by a single modality of MRI and investigated static functional connectivity (FC) in TMD. By combining structural and functional MRI data, the present study aimed to identify brain regions with structural abnormalities in TMD patients and examine static and dynamic FC seeded by these regions to investigate structural brain alterations and related disrupted FC underlying the pathophysiology of TMD. METHODS We recruited 30 TMD patients and 20 healthy controls who underwent 3.0 T MRI scanning with T1-weighted images using a three-dimensional magnetization-prepared rapid gradient-echo sequence and resting state functional images using a gradient-echo echo-planar imaging sequence. Cortical thickness, volume, surface area, and subcortical volume were calculated, where brain areas with significant structural between-group differences were treated as seeds for static and dynamic FC analyses. RESULTS In this preliminary study, we found between-group alterations in sensorimotor regions including decreased cortical thickness in the right sensorimotor cortex as well as decreased volume in the left putamen and associated reduced dynamic FC with the anterior midcingulate cortex; and alterations in emotion processing and regulation regions including decreased volume/surface area in the left posterior superior temporal gyrus and associated increased dynamic FC with the precuneus in TMD patients than controls, having all p < 0.05 with corrections for multiple comparisons. CONCLUSION Our findings of structural and functional abnormalities in brain regions implicated in sensorimotor and emotional functions provided evidence for the biopsychosocial model of TMD and facilitated our understanding of the pathophysiological mechanism underlying TMD. The associations between neuroimaging results and clinical measurements of TMD warrant further exploration.
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Affiliation(s)
- Yuanyuan Yin
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Shushu He
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ning He
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, China
| | - Wenjing Zhang
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Lekai Luo
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Lizhou Chen
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Ting Liu
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mi Tian
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jingchen Xu
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Song Chen
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Fei Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
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5
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Shrivastava M, Ye L. Neuroimaging and artificial intelligence for assessment of chronic painful temporomandibular disorders-a comprehensive review. Int J Oral Sci 2023; 15:58. [PMID: 38155153 PMCID: PMC10754947 DOI: 10.1038/s41368-023-00254-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 12/30/2023] Open
Abstract
Chronic Painful Temporomandibular Disorders (TMD) are challenging to diagnose and manage due to their complexity and lack of understanding of brain mechanism. In the past few decades' neural mechanisms of pain regulation and perception have been clarified by neuroimaging research. Advances in the neuroimaging have bridged the gap between brain activity and the subjective experience of pain. Neuroimaging has also made strides toward separating the neural mechanisms underlying the chronic painful TMD. Recently, Artificial Intelligence (AI) is transforming various sectors by automating tasks that previously required humans' intelligence to complete. AI has started to contribute to the recognition, assessment, and understanding of painful TMD. The application of AI and neuroimaging in understanding the pathophysiology and diagnosis of chronic painful TMD are still in its early stages. The objective of the present review is to identify the contemporary neuroimaging approaches such as structural, functional, and molecular techniques that have been used to investigate the brain of chronic painful TMD individuals. Furthermore, this review guides practitioners on relevant aspects of AI and how AI and neuroimaging methods can revolutionize our understanding on the mechanisms of painful TMD and aid in both diagnosis and management to enhance patient outcomes.
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Affiliation(s)
- Mayank Shrivastava
- Adams School of Dentistry, University of North Carolina, Chapel Hill, NC, USA
| | - Liang Ye
- Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, MN, USA.
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6
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Salberg S, Li CN, Beveridge JK, Noel M, Yamakawa GR, Mychasiuk R. Gene expression changes in the cerebellum are associated with persistent post-injury pain in adolescent rats exposed to early life stress. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 14:100145. [PMID: 38099278 PMCID: PMC10719517 DOI: 10.1016/j.ynpai.2023.100145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 12/17/2023]
Abstract
Chronic pain develops following injury in approximately 20% of adolescents, at twice the rate in females than males. Adverse childhood experiences also increase the risk for poor health outcomes, such as chronic pain. Emerging literature suggests the cerebellum to be involved in pain processing, however detailed explorations into how the cerebellum contributes to pain are lacking. Therefore, this study aimed to characterise chronic pain outcomes and cerebellar gene expression changes following early life stress and injury in both sexes. The adverse childhood experience of neglect was modelled using a maternal separation (MS) paradigm, which was combined with a subsequent injury (mild traumatic brain injury (mTBI) or plantar incision surgery) in adolescent male and female Sprague-Dawley rats. We measured behavioural nociceptive sensitivity, systemic modulators of pain such as calcitonin gene-related protein (CGRP) and Substance P, as well as gene expression of IL1β, GFAP, GR, MR, GABRA1, CNR1, MAOA, and DAT1 in the cerebellum to examine associations between pain and neuroinflammation, the stress response, inhibitory neurotransmission, and monoaminergic function. We found increases in mechanical nociceptive sensitivity following plantar incision surgery. Sex differences were observed in anxiety-like behaviour and neuroinflammation, whereas systemic pain modulators showed cumulative effects with the addition of stressors. Most interestingly however, the increases in nociceptive sensitivity were associated with the suppressed expression of cerebellar genes that regulate stress, inhibition, cannabinoid function, and dopaminergic function, alongside sex-dependent distinctions for genes involved in inflammation and injury. This study highlights a novel link between nociception and molecular function in the cerebellum. Further investigation into how the cerebellum contributes to pain in males and females will facilitate novel therapeutic insights and opportunities.
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Affiliation(s)
- Sabrina Salberg
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - Crystal N. Li
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - Jaimie K. Beveridge
- Department of Psychology, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, The University of Calgary, Calgary, AB, Canada
| | - Melanie Noel
- Department of Psychology, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, The University of Calgary, Calgary, AB, Canada
| | - Glenn R. Yamakawa
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
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7
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Peck CM, Bereiter DA, Eberly LE, Lenglet C, Moana-Filho EJ. Altered brain responses to noxious dentoalveolar stimuli in high-impact temporomandibular disorder pain patients. PLoS One 2022; 17:e0266349. [PMID: 36240243 PMCID: PMC9565712 DOI: 10.1371/journal.pone.0266349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/25/2022] [Indexed: 11/05/2022] Open
Abstract
High-impact temporomandibular disorder (TMD) pain may involve brain mechanisms related to maladaptive central pain modulation. We investigated brain responses to stimulation of trigeminal sites not typically associated with TMD pain by applying noxious dentoalveolar pressure to high- and low-impact TMD pain cases and pain-free controls during functional magnetic resonance imaging (fMRI). Fifty female participants were recruited and assigned to one of three groups based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and Graded Chronic Pain Scale: controls (n = 17), low-impact (n = 17) and high-impact TMD (n = 16). Multimodal whole-brain MRI was acquired following the Human Connectome Project Lifespan protocol, including stimulus-evoked fMRI scans during which painful dentoalveolar pressure was applied to the buccal gingiva of participants. Group analyses were performed using non-parametric permutation tests for parcellated cortical and subcortical neuroimaging data. There were no significant between-group differences for brain activations/deactivations evoked by the noxious dentoalveolar pressure. For individual group mean activations/deactivations, a gradient in the number of parcels surviving thresholding was found according to the TMD pain grade, with the highest number seen in the high-impact group. Among the brain regions activated in chronic TMD pain groups were those previously implicated in sensory-discriminative and motivational-affective pain processing. These results suggest that dentoalveolar pressure pain evokes abnormal brain responses to sensory processing of noxious stimuli in high-impact TMD pain participants, which supports the presence of maladaptive brain plasticity in chronic TMD pain.
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Affiliation(s)
- Connor M. Peck
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - David A. Bereiter
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Lynn E. Eberly
- Division of Biostatistics, University of Minnesota School of Public Health, Minneapolis, Minnesota, United States of America
| | - Christophe Lenglet
- Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Estephan J. Moana-Filho
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
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8
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Vamvakas A, Lawn T, Veronese M, Williams SCR, Tsougos I, Howard MA. Neurotransmitter receptor densities are associated with changes in regional Cerebral blood flow during clinical ongoing pain. Hum Brain Mapp 2022; 43:5235-5249. [PMID: 35796178 PMCID: PMC9812236 DOI: 10.1002/hbm.25999] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 05/07/2022] [Accepted: 06/19/2022] [Indexed: 01/15/2023] Open
Abstract
Arterial spin labelling (ASL) plays an increasingly important role in neuroimaging pain research but does not provide molecular insights regarding how regional cerebral blood flow (rCBF) relates to underlying neurotransmission. Here, we integrate ASL with positron emission tomography (PET) and brain transcriptome data to investigate the molecular substrates of rCBF underlying clinically relevant pain states. Two data sets, representing acute and chronic ongoing pain respectively, were utilised to quantify changes in rCBF; one examining pre-surgical versus post-surgical pain, and the second comparing patients with painful hand Osteoarthritis to a group of matched controls. We implemented a whole-brain spatial correlation analysis to explore associations between change in rCBF (ΔCBF) and neurotransmitter receptor distributions derived from normative PET templates. Additionally, we utilised transcriptomic data from the Allen Brain Atlas to inform distributions of receptor expression. Both datasets presented significant correlations of ΔCBF with the μ-opioid and dopamine-D2 receptor expressions, which play fundamental roles in brain activity associated with pain experiences. ΔCBF also correlated with the gene expression distributions of several receptors involved in pain processing. Overall, this is the first study illustrating the molecular basis of ongoing pain ASL indices and emphasises the potential of rCBF as a biomarker in pain research.
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Affiliation(s)
- Alexandros Vamvakas
- Medical Physics Department, Medical SchoolUniversity of ThessalyLarisaGreece,Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
| | - Timothy Lawn
- Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
| | - Steven C. R. Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
| | - Ioannis Tsougos
- Medical Physics Department, Medical SchoolUniversity of ThessalyLarisaGreece,Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
| | - Matthew A. Howard
- Department of Neuroimaging, Institute of Psychiatry, Psychology and NeuroscienceKing's College LondonLondonUK
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9
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Zhang F, Li F, Yang H, Jin Y, Lai W, Kemp GJ, Jia Z, Gong Q. Altered Brain Topological Property Associated With Anxiety in Experimental Orthodontic Pain. Front Neurosci 2022; 16:907216. [PMID: 35645708 PMCID: PMC9132585 DOI: 10.3389/fnins.2022.907216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/21/2022] [Indexed: 11/17/2022] Open
Abstract
Background Orthodontic pain is orofacial pain caused by tooth movement. Anxiety is a strong predictor of the severity of such pain, but little is known about the underlying neuropsychological mechanisms of such effects. The purpose of this study was to investigate the effect of orthodontic pain on brain functional networks and to define the mediating role of anxiety in orthodontic pain and brain function. Methods Graph theory-based network analyses were applied to brain functional magnetic resonance imaging data from 48 healthy participants exposed to 24 h orthodontic pain stimuli and 49 healthy controls without any stimulation. Results In the experimental orthodontic pain stimulation, brain functional networks retained a small-world organization. At the regional level, the nodal centrality of ipsilateral brain nodes to the pain stimulus was enhanced; in contrast the nodal centrality of contralateral brain areas was decreased, especially the right mid-cingulate cortex, which is involved in pain intensity coding. Furthermore, anxiety mediated the relationship between nodal efficiency of mid-cingulate cortex and pain severity. Conclusion The results illuminate the neural mechanisms of orthodontic pain by revealing unbalanced hemispherical brain function related to the unilateral pain stimulation, and reveal clinically exploitable evidence that anxiety mediates the relationship between nodal function of right mid-cingulate cortex and orthodontic pain.
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Affiliation(s)
- Feifei Zhang
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
- Department of Radiology, First Hospital of Shanxi Medical University, Taiyuan, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, China
| | - Fei Li
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, China
| | - Hong Yang
- State Key Laboratory of Oral Disease, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Yu Jin
- State Key Laboratory of Oral Disease, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Wenli Lai
- State Key Laboratory of Oral Disease, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Graham J. Kemp
- Liverpool Magnetic Resonance Imaging Centre (LiMRIC) and Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Zhiyun Jia
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, China
- *Correspondence: Zhiyun Jia,
| | - Qiyong Gong
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, China
- Functional and Molecular Imaging Key Laboratory of Sichuan University, Chengdu, China
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10
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Pondelis NJ, Moulton EA. Supraspinal Mechanisms Underlying Ocular Pain. Front Med (Lausanne) 2022; 8:768649. [PMID: 35211480 PMCID: PMC8862711 DOI: 10.3389/fmed.2021.768649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/27/2021] [Indexed: 12/04/2022] Open
Abstract
Supraspinal mechanisms of pain are increasingly understood to underlie neuropathic ocular conditions previously thought to be exclusively peripheral in nature. Isolating individual causes of centralized chronic conditions and differentiating them is critical to understanding the mechanisms underlying neuropathic eye pain and ultimately its treatment. Though few functional imaging studies have focused on the eye as an end-organ for the transduction of noxious stimuli, the brain networks related to pain processing have been extensively studied with functional neuroimaging over the past 20 years. This article will review the supraspinal mechanisms that underlie pain as they relate to the eye.
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Affiliation(s)
- Nicholas J Pondelis
- Brain and Eye Pain Imaging Lab, Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Eric A Moulton
- Brain and Eye Pain Imaging Lab, Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
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11
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Zhang P, Jiang Y, Liu G, Han J, Wang J, Ma L, Hu W, Zhang J. Altered brain functional network dynamics in classic trigeminal neuralgia: a resting-state functional magnetic resonance imaging study. J Headache Pain 2021; 22:147. [PMID: 34895135 PMCID: PMC8903588 DOI: 10.1186/s10194-021-01354-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/06/2021] [Indexed: 12/20/2022] Open
Abstract
Background Accumulating studies have indicated a wide range of brain alterations with respect to the structure and function of classic trigeminal neuralgia (CTN). Given the dynamic nature of pain experience, the exploration of temporal fluctuations in interregional activity covariance may enhance the understanding of pain processes in the brain. The present study aimed to characterize the temporal features of functional connectivity (FC) states as well as topological alteration in CTN. Methods Resting-state functional magnetic resonance imaging and three-dimensional T1-weighted images were obtained from 41 CTN patients and 43 matched healthy controls (HCs). After group independent component analysis, sliding window based dynamic functional network connectivity (dFNC) analysis was applied to investigate specific FC states and related temporal properties. Then, the dynamics of the whole brain topological organization were estimated by calculating the coefficient of variation of graph-theoretical properties. Further correlation analyses were performed between all these measurements and clinical data. Results Two distinct states were identified. Of these, the state 2, characterized by complicated coupling between default mode network (DMN) and cognitive control network (CC) and tight connections within DMN, was expressed more in CTN patients and presented as increased fractional windows and dwell time. Moreover, patients switched less frequently between states than HCs. Regarding the dynamic topological analysis, disruptions in global graph-theoretical properties (including network efficiency and small-worldness) were observed in patients, coupled with decreased variability in nodal efficiency of anterior cingulate cortex (ACC) in the salience network (SN) and the thalamus and caudate nucleus in the subcortical network (SC). The variation of topological properties showed negative correlation with disease duration and attack frequency. Conclusions The present study indicated disrupted flexibility of brain topological organization under persistent noxious stimulation and further highlighted the important role of “dynamic pain connectome” regions (including DMN/CC/SN) in the pathophysiology of CTN from the temporal fluctuation aspect. Additionally, the findings provided supplementary evidence for current knowledge about the aberrant cortical-subcortical interaction in pain development. Supplementary Information The online version contains supplementary material available at 10.1186/s10194-021-01354-z.
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Affiliation(s)
- Pengfei Zhang
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China.,Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Yanli Jiang
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China.,Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Guangyao Liu
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China.,Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Jiao Han
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China
| | - Jun Wang
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China.,Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Laiyang Ma
- Second Clinical School, Lanzhou University, Lanzhou, 730000, China.,Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Wanjun Hu
- Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China
| | - Jing Zhang
- Department of Magnetic Resonance, Lanzhou University Second Hospital, Lanzhou, 730000, China. .,Gansu Province Clinical Research Center for Functional and Molecular Imaging, Cuiyingmen No.82, Chengguan District, Lanzhou, 730030, P. R. China.
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12
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Elina KC, Oh BH, Islam J, Kim S, Park YS. Activation of CamKIIα expressing neurons on ventrolateral periaqueductal gray improves behavioral hypersensitivity and thalamic discharge in a trigeminal neuralgia rat model. J Headache Pain 2021; 22:47. [PMID: 34044756 PMCID: PMC8161973 DOI: 10.1186/s10194-021-01257-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/11/2021] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Preceding studies have reported the association of chronic neuropathic orofacial pain with altered ongoing function in the ventrolateral periaqueductal gray (vlPAG). However, its role in trigeminal neuralgia (TN) lacks attention. We here reported the aspect that vlPAG neurons play in TN nociceptive processing by employing excitatory neuron-specific optogenetic approaches. METHODS TN was generated via unilateral infraorbital nerve chronic constriction in Sprague Dawley rats which induced mechanical and thermal pain sensitivity in air puff and acetone test, respectively. Channelrhodopsin conjugated virus with CamKIIα promoter was used to specifically activate the excitatory vlPAG neuronal population by optogenetic stimulation and in vivo microdialysis was done to determine its effect on the excitatory-inhibitory balance. In vivo extracellular recordings from ventral posteromedial (VPM) thalamus were assessed in response to vlPAG optogenetic stimulation. Depending on the experimental terms, unpaired student's t test and two-way analysis of variance (ANOVA) were used for statistical analysis. RESULTS We observed that optogenetic activation of vlPAG subgroup neurons markedly improved pain hypersensitivity in reflexive behavior tests which was also evident on microdialysis analysis with increase glutamate concentration during stimulation period. Decreased mean firing and burst rates were evident in VPM thalamic electrophysiological recordings during the stimulation period. Overall, our results suggest the optogenetic activation of vlPAG excitatory neurons in a TN rat model has pain ameliorating effect. CONCLUSIONS This article presents the prospect of pain modulation in trigeminal pain pathway via optogenetic activation of vlPAG excitatory neurons in rat model. This outlook could potentially assist vlPAG insight and its optogenetic approach in trigeminal neuropathic pain which aid clinicians endeavoring towards enhanced pain relief therapy in trigeminal neuralgia patients.
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Affiliation(s)
- K C Elina
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Byeong Ho Oh
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
- Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, South Korea
| | - Jaisan Islam
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Soochong Kim
- Department of Veterinary Medicine, Chungbuk National University, Cheongju, South Korea
| | - Young Seok Park
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea.
- Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, South Korea.
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13
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Increased substance P and synaptic remodeling occur in the trigeminal sensory system with sustained osteoarthritic temporomandibular joint sensitivity. Pain Rep 2021; 6:e911. [PMID: 33977183 PMCID: PMC8104398 DOI: 10.1097/pr9.0000000000000911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/24/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. Increased substance P and a loss of inhibitory synapses occurs within the brain's trigeminal sensory system with persistent, but not transient, temporomandibular joint sensitivity. Introduction: Temporomandibular joint (TMJ) pain is among the most prevalent musculoskeletal conditions and can result from atypical joint loading. Although TMJ pain is typically self-resolving, 15% of patients develop chronic TMJ pain that is recalcitrant to therapy and may be attributed to changes in pain processing centers. Although TMJ overloading induces pain and osteoarthritis, whether neuronal modifications in the trigeminal sensory system contribute to persistent TMJ pain is unknown. Objective: This study investigates changes in excitatory neuropeptides and synaptic transmission proteins in cases of transient and persistent TMJ sensitivity in a rat model. Methods: Rats underwent repeated jaw loading that produces transient (2N-load) or persistent (3.5N-load) sensitivity. In both groups, immunolabeling was used to assess substance P in the spinal trigeminal nucleus caudalis (Sp5C) and glutamate transporter 1 in the ventroposteriomedial thalamus early after loading. Synaptosomal Western blots were used to measure synaptic proteins in the caudal medulla and thalamus at a later time after loading. Results: Substance P increases transiently in the Sp5C early after loading that induces persistent sensitivity. However, glutamate transporter 1 is unchanged in the ventroposteriomedial thalamus. At a later time, synaptosomal Western blots show loss of the presynaptic tethering protein, synapsin, and the inhibitory scaffolding protein, gephyrin, in the thalamus with persistent, but not transient, sensitivity. No changes are identified in synapsin, phosphorylated synapsin, homer, or gephyrin in the caudal medulla. Conclusions: Substance P in the Sp5C and later loss of inhibitory synapses in the thalamus likely contribute to, or indicate, persistent TMJ pain.
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14
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McIlwrath SL, Starr ME, High AE, Saito H, Westlund KN. Effect of acetyl-L-carnitine on hypersensitivity in acute recurrent caerulein-induced pancreatitis and microglial activation along the brain’s pain circuitry. World J Gastroenterol 2021; 27:794-814. [PMID: 33727771 PMCID: PMC7941858 DOI: 10.3748/wjg.v27.i9.794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/08/2020] [Accepted: 01/15/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Acute pancreatitis (AP) and recurring AP are serious health care problems causing excruciating pain and potentially lethal outcomes due to sepsis. The validated caerulein- (CAE) induced mouse model of acute/recurring AP produces secondary persistent hypersensitivity and anxiety-like behavioral changes for study.
AIM To determine efficacy of acetyl-L-carnitine (ALC) to reduce pain-related behaviors and brain microglial activation along the pain circuitry in CAE-pancreatitis.
METHODS Pancreatitis was induced with 6 hly intraperitoneal (i.p.) injections of CAE (50 µg/kg), 3 d a week for 6 wk in male C57BL/6J mice. Starting in week 4, mice received either vehicle or ALC until experiment’s end. Mechanical hyper-sensitivity was assessed with von Frey filaments. Heat hypersensitivity was determined with the hotplate test. Anxiety-like behavior was tested in week 6 using elevated plus maze and open field tests. Microglial activation in brain was quantified histologically by immunostaining for ionized calcium-binding adaptor molecule 1 (Iba1).
RESULTS Mice with CAE-induced pancreatitis had significantly reduced mechanical withdrawal thresholds and heat response latencies, indicating ongoing pain. Treatment with ALC attenuated inflammation-induced hypersensitivity, but hypersensitivity due to abdominal wall injury caused by repeated intraperitoneal injections persisted. Animals with pancreatitis displayed spontaneous anxiety-like behavior in the elevated plus maze compared to controls. Treatment with ALC resulted in increased numbers of rearing activity events, but time spent in “safety” was not changed. After all the abdominal injections, pancreata were translucent if excised at experiment’s end and opaque if excised on the subsequent day, indicative of spontaneous healing. Post mortem histopathological analysis performed on pancreas sections stained with Sirius Red and Fast Green identified wide-spread fibrosis and acinar cell atrophy in sections from mice with CAE-induced pancreatitis that was not rescued by treatment with ALC. Microglial Iba1 immunostaining was significantly increased in hippocampus, thalamus (intralaminar nuclei), hypothalamus, and amygdala of mice with CAE-induced pancreatitis compared to naïve controls but unchanged in the primary somatosensory cortex compared to naïves.
CONCLUSION CAE-induced pancreatitis caused increased pain-related behaviors, pancreatic fibrosis, and brain microglial changes. ALC alleviated CAE-induced mechanical and heat hypersensitivity but not abdominal wall injury-induced hypersensitivity caused by the repeated injections.
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Affiliation(s)
- Sabrina L McIlwrath
- Research Service, New Mexico Veterans Affairs Healthcare System, Albuquerque, NM 87108, United States
| | - Marlene E Starr
- Department of Surgery, University of Kentucky, Lexington, KY 40536, United States
| | - Abigail E High
- College of Liberal Arts, University of Texas, Austin, TX 78712, United States
| | - Hiroshi Saito
- Department of Surgery, University of Kentucky, Lexington, KY 40536, United States
| | - Karin N Westlund
- Research Service, New Mexico Veterans Affairs Healthcare System, Albuquerque, NM 87108, United States
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
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15
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Müller M, Wüthrich F, Federspiel A, Wiest R, Egloff N, Reichenbach S, Exadaktylos A, Jüni P, Curatolo M, Walther S. Altered central pain processing in fibromyalgia-A multimodal neuroimaging case-control study using arterial spin labelling. PLoS One 2021; 16:e0235879. [PMID: 33529254 PMCID: PMC7853499 DOI: 10.1371/journal.pone.0235879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 01/19/2021] [Indexed: 01/12/2023] Open
Abstract
Fibromyalgia is characterized by chronic pain and a striking discrepancy between objective signs of tissue damage and severity of pain. Function and structural alterations in brain areas involved in pain processing may explain this feature. Previous case-control studies in fibromyalgia focused on acute pain processing using experimentally-evoked pain paradigms. Yet, these studies do not allow conclusions about chronic, stimulus-independent pain. Resting-state cerebral blood flow (rsCBF) acquired by arterial spin labelling (ASL) may be a more accurate marker for chronic pain. The objective was to integrate four different functional and structural neuroimaging markers to evaluate the neural correlate of chronic, stimulus-independent pain using a resting-state paradigm. In line with the pathophysiological concept of enhanced central pain processing we hypothesized that rsCBF is increased in fibromyalgia in areas involved in processing of acute pain. We performed an age matched case-control study of 32 female fibromyalgia patients and 32 pain-free controls and calculated group differences in rsCBF, resting state functional connectivity, grey matter volume and cortical thickness using whole-brain and region of interest analyses. We adjusted all analyses for depression and anxiety. As centrally acting drugs are likely to interfere with neuroimaging markers, we performed a subgroup analysis limited to patients not taking such drugs. We found no differences between cases and controls in rsCBF of the thalamus, the basal ganglia, the insula, the somatosensory cortex, the prefrontal cortex, the anterior cingulum and supplementary motor area as brain areas previously identified to be involved in acute processing in fibromyalgia. The results remained robust across all neuroimaging markers and when limiting the study population to patients not taking centrally acting drugs and matched controls. In conclusion, we found no evidence for functional or structural alterations in brain areas involved in acute pain processing in fibromyalgia that could reflect neural correlates of chronic stimulus-independent pain.
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Affiliation(s)
- Monika Müller
- University Clinic of Anesthesiology and Pain Medicine, Inselspital, Bern, Switzerland
- Translational Research Center, University Hospital of Psychiatry and Psychotherapy, Bern, Switzerland
| | - Florian Wüthrich
- Translational Research Center, University Hospital of Psychiatry and Psychotherapy, Bern, Switzerland
| | - Andrea Federspiel
- Translational Research Center, University Hospital of Psychiatry and Psychotherapy, Bern, Switzerland
| | - Roland Wiest
- Department of Neuroradiology, University Clinic of Radiology, Inselspital, Bern, Switzerland
| | - Niklaus Egloff
- Department of Psychosomatic Medicine, University Clinic of Internal Medicine, Inselspital, Bern, Switzerland
| | - Stephan Reichenbach
- University Clinic of Rheumatology, Clinical Immunology and Allergology, Inselspital, Bern, Switzerland
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | | | - Peter Jüni
- Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Department of Medicine, University of Toronto, Toronto, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada
| | - Michele Curatolo
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, United States of America
| | - Sebastian Walther
- Translational Research Center, University Hospital of Psychiatry and Psychotherapy, Bern, Switzerland
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16
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Mills EP, Alshelh Z, Kosanovic D, Di Pietro F, Vickers ER, Macey PM, Henderson LA. Altered Brainstem Pain-Modulation Circuitry Connectivity During Spontaneous Pain Intensity Fluctuations. J Pain Res 2020; 13:2223-2235. [PMID: 32943915 PMCID: PMC7481287 DOI: 10.2147/jpr.s252594] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/07/2020] [Indexed: 11/23/2022] Open
Abstract
Background Chronic pain, particularly that following nerve injury, can occur in the absence of external stimuli. Although the ongoing pain is sometimes continuous, in many individuals the intensity of their pain fluctuates. Experimental animal studies have shown that the brainstem contains circuits that modulate nociceptive information at the primary afferent synapse and these circuits are involved in maintaining ongoing continuous neuropathic pain. However, it remains unknown if these circuits are involved in regulating fluctuations of ongoing neuropathic pain in humans. Methods We used functional magnetic resonance imaging to determine whether in 19 subjects with painful trigeminal neuropathy, brainstem pain-modulation circuitry function changes according to moment-to-moment fluctuations in spontaneous pain intensity as rated online over a 12-minute period. Results We found that when pain intensity was spontaneously high, connectivity strengths between regions of the brainstem endogenous pain-modulating circuitry-the midbrain periaqueductal gray, rostral ventromedial medulla (RVM), and the spinal trigeminal nucleus (SpV)-were high, and vice-versa (when pain was low, connectivity was low). Additionally, sliding-window connectivity analysis using 50-second windows revealed a significant positive relationship between ongoing pain intensity and RVM-SpV connectivity over the duration of the 12-minute scan. Conclusion These data reveal that moment-to-moment changes in brainstem pain-modulation circuitry functioning likely contribute to fluctuations in spontaneous pain intensity in individuals with chronic neuropathic pain.
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Affiliation(s)
- Emily P Mills
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Zeynab Alshelh
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Danny Kosanovic
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Flavia Di Pietro
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - E Russell Vickers
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
| | - Paul M Macey
- School of Nursing and Brain Research Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia
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17
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McIlwrath SL, Montera MA, Gott KM, Yang Y, Wilson CM, Selwyn R, Westlund KN. Manganese-enhanced MRI reveals changes within brain anxiety and aversion circuitry in rats with chronic neuropathic pain- and anxiety-like behaviors. Neuroimage 2020; 223:117343. [PMID: 32898676 PMCID: PMC8858643 DOI: 10.1016/j.neuroimage.2020.117343] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 08/11/2020] [Accepted: 08/31/2020] [Indexed: 01/31/2023] Open
Abstract
Chronic pain often predicts the onset of psychological distress. Symptoms including anxiety and depression after pain chronification reportedly are caused by brain remodeling/recruitment of the limbic and reward/aversion circuitries. Pain is the primary precipitating factor that has caused opioid overprescribing and continued overuse of opioids leading to the current opioid epidemic. Yet experimental pain therapies often fail in clinical trials. Better understanding of underlying pathologies contributing to pain chronification is needed to address these chronic pain related issues. In the present study, a chronic neuropathic pain model persisting 10 weeks was studied. The model develops both anxiety- and pain-related behavioral measures to mimic clinical pain. The manganese-enhanced magnetic resonance imaging (MEMRI) utilized improved MRI signal contrast in brain regions with higher neuronal activity in the rodent chronic constriction trigeminal nerve injury (CCI-ION) model. T1-weighted MEMRI signal intensity was increased compared to controls in supraspinal regions of the anxiety and aversion circuitry, including anterior cingulate gyrus (ACC), amygdala, habenula, caudate, ventrolateral and dorsomedial periaqueductal gray (PAG). Despite continuing mechanical hypersensitivity, MEMRI T1 signal intensity as the neuronal activity measure, was not significantly different in thalamus and decreased in somatosensory cortex (S1BF) of CCI-ION rats compared to naïve controls. This is consistent with decreased fMRI BOLD signal intensity in thalamus and cortex of patients with longstanding trigeminal neuropathic pain reportedly associated with gray matter volume decrease in these regions. Significant increase in MEMRI T2 signal intensity in thalamus of CCI-ION animals was indication of tissue water content, cell dysfunction and/or reactive astrogliosis. Decreased T2 signal intensity in S1BF cortex of rats with CCI-ION was similar to findings of reduced T2 signals in clinical patients with chronic orofacial pain indicating prolonged astrocyte activation. These findings support use of MEMRI and chronic rodent models for preclinical studies and therapeutic trials to reveal brain sites activated only after neuropathic pain has persisted in timeframes relevant to clinical pain and to observe treatment effects not possible in short-term models which do not have evidence of anxiety-like behaviors. Potential improvement is predicted in the success rate of preclinical drug trials in future studies with this model.
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Affiliation(s)
| | - Marena A Montera
- University of New Mexico Health Sciences Center, Albuquerque, NM USA
| | - Katherine M Gott
- University of New Mexico Health Sciences Center, Albuquerque, NM USA
| | - Yirong Yang
- University of New Mexico Health Sciences Center, Albuquerque, NM USA
| | - Colin M Wilson
- University of New Mexico Health Sciences Center, Albuquerque, NM USA
| | - Reed Selwyn
- University of New Mexico Health Sciences Center, Albuquerque, NM USA
| | - Karin N Westlund
- Research Services New Mexico VA HealthCare System Albuquerque NM 87108 USA; University of New Mexico Health Sciences Center, Albuquerque, NM USA
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18
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Mills EP, Akhter R, Di Pietro F, Murray GM, Peck CC, Macey PM, Henderson LA. Altered Brainstem Pain Modulating Circuitry Functional Connectivity in Chronic Painful Temporomandibular Disorder. THE JOURNAL OF PAIN 2020; 22:219-232. [PMID: 32896638 DOI: 10.1016/j.jpain.2020.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 08/12/2020] [Accepted: 08/22/2020] [Indexed: 11/29/2022]
Abstract
There is evidence from preclinical models of chronic pain and human psychophysical investigations to suggest that alterations in endogenous brainstem pain-modulation circuit functioning are critical for the initiation and/or maintenance of pain. Whilst preclinical models have begun to explore the functioning of this circuitry in chronic pain, little is known about such functioning in humans with chronic pain. The aim of this investigation was to determine whether individuals with chronic non-neuropathic pain, painful temporomandibular disorders (TMD), display alterations in brainstem pain-modulating circuits. Using resting-state functional magnetic resonance imaging, we performed static and dynamic functional connectivity (FC) analyses to assess ongoing circuit function in 16 TMD and 45 control subjects. We calculated static FC as the correlation of functional magnetic resonance imaging signals between regions over the entire scan and dynamic FC as the correlation of signals in short (50s) windows. Compared with controls, TMD subjects showed significantly greater (static) FC between the rostral ventromedial medulla and both the subnucleus reticularis dorsalis and the region that receives orofacial nociceptive afferents, the spinal trigeminal nucleus. No differences were found in other brainstem pain-modulating regions such as the midbrain periaqueductal gray matter and locus coeruleus. We also identified that TMD subjects experience greater variability in the dynamic functional connections between the rostral ventromedial medulla and both the subnucleus reticularis dorsalis and spinal trigeminal nucleus. These changes may underlie enhanced descending pain-facilitating actions over the region that receives nociceptive afferents, ultimately leading to enhanced nociceptive transmission to higher brain regions and thus contributing to the ongoing perception of pain. PERSPECTIVE: Psychophysical studies suggest that brainstem pain-modulation circuits contribute to the maintenance of chronic pain. We report that individuals with painful TMD display altered static and dynamic FC within the brainstem pain-modulation network. Modifying this circuitry may alter an individual's ongoing pain.
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Affiliation(s)
- Emily P Mills
- Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia
| | - Rahena Akhter
- Sydney Dental School, University of Sydney, Sydney, New South Wales, Australia
| | - Flavia Di Pietro
- Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia
| | - Greg M Murray
- Sydney Dental School, University of Sydney, Sydney, New South Wales, Australia
| | - Chris C Peck
- Sydney Dental School, University of Sydney, Sydney, New South Wales, Australia
| | - Paul M Macey
- UCLA School of Nursing and Brain Research Institute, University of California, Los Angeles, California
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia.
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19
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Wang Z, Huang S, Yu X, Li L, Yang M, Liang S, Liu W, Tao J. Altered thalamic neurotransmitters metabolism and functional connectivity during the development of chronic constriction injury induced neuropathic pain. Biol Res 2020; 53:36. [PMID: 32843088 PMCID: PMC7448455 DOI: 10.1186/s40659-020-00303-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/08/2020] [Indexed: 11/17/2022] Open
Abstract
Background To investigate the thalamic neurotransmitters and functional connections in the development of chronic constriction injury (CCI)-induced neuropathic pain. Methods The paw withdrawal threshold was measured by mechanical stimulation the right hind paw with the von frey hair in the rats of CCI-induced neuropathic pain. The N-acetylaspartate (NAA) and Glutamate (Glu) in thalamus were detected by magnetic resonance spectrum (MRS) process. The thalamic functional connectivity with other brain regions was scanned by functional magnetic resonance image (fMRI). Results The paw withdrawal threshold of the ipsilateral side showed a noticeable decline during the pathological process. Increased concentrations of Glu and decreased levels of NAA in the thalamus were significantly correlated with mechanical allodynia in the neuropathic pain states. The thalamic regional homogeneity (ReHo) decreased during the process of neuropathic pain. The functional connectivity among the thalamus with the insula and somatosensory cortex were significantly increased at different time points (7, 14, 21 days) after CCI surgery. Conclusion Our study suggests that dynamic changes in thalamic NAA and Glu levels contribute to the thalamic functional connection hyper-excitation during CCI-induced neuropathic pain. Enhanced thalamus-insula functional connection might have a significant effect on the occurrence of neuropathic pain.
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Affiliation(s)
- Zhifu Wang
- College of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Sheng Huang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Xiangmei Yu
- College of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Long Li
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Minguang Yang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Shengxiang Liang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Weilin Liu
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Jing Tao
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
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20
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Yin Y, He S, Xu J, You W, Li Q, Long J, Luo L, Kemp GJ, Sweeney JA, Li F, Chen S, Gong Q. The neuro-pathophysiology of temporomandibular disorders-related pain: a systematic review of structural and functional MRI studies. J Headache Pain 2020; 21:78. [PMID: 32560622 PMCID: PMC7304152 DOI: 10.1186/s10194-020-01131-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/25/2020] [Indexed: 02/08/2023] Open
Abstract
Chronic pain surrounding the temporomandibular joints and masticatory muscles is often the primary chief complaint of patients with temporomandibular disorders (TMD) seeking treatment. Yet, the neuro-pathophysiological basis underlying it remains to be clarified. Neuroimaging techniques have provided a deeper understanding of what happens to brain structure and function in TMD patients with chronic pain. Therefore, we performed a systematic review of magnetic resonance imaging (MRI) studies investigating structural and functional brain alterations in TMD patients to further unravel the neurobiological underpinnings of TMD-related pain. Online databases (PubMed, EMBASE, and Web of Science) were searched up to August 3, 2019, as complemented by a hand search in reference lists. A total of 622 papers were initially identified after duplicates removed and 25 studies met inclusion criteria for this review. Notably, the variations of MRI techniques used and study design among included studies preclude a meta-analysis and we discussed the findings qualitatively according to the specific neural system or network the brain regions were involved in. Brain changes were found in pathways responsible for abnormal pain perception, including the classic trigemino-thalamo-cortical system and the lateral and medial pain systems. Dysfunction and maladaptive changes were also identified in the default mode network, the top-down antinociceptive periaqueductal gray-raphe magnus pathway, as well as the motor system. TMD patients displayed altered brain activations in response to both innocuous and painful stimuli compared with healthy controls. Additionally, evidence indicates that splint therapy can alleviate TMD-related symptoms by inducing functional brain changes. In summary, MRI research provides important novel insights into the altered neural manifestations underlying chronic pain in TMD.
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Affiliation(s)
- Yuanyuan Yin
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Shushu He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Jingchen Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Wanfang You
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Qian Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Jingyi Long
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Lekai Luo
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Graham J Kemp
- Liverpool Magnetic Resonance Imaging Centre (LiMRIC) and Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - John A Sweeney
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Department of Psychiatry, University of Cincinnati, Cincinnati, OH, USA
| | - Fei Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China. .,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.
| | - Song Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.,Psychoradiology Research Unit of Chinese Academy of Medical Sciences, Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
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21
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Di Pietro F, Lee B, Henderson LA. Altered resting activity patterns and connectivity in individuals with complex regional pain syndrome. Hum Brain Mapp 2020; 41:3781-3793. [PMID: 32510695 PMCID: PMC7416050 DOI: 10.1002/hbm.25087] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 12/20/2022] Open
Abstract
Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder that typically occurs in the limbs, usually the upper limb. CRPS usually develops from a peripheral event but its maintenance relies on changes within the central nervous system. While functional abnormalities in the thalamus and primary somatosensory cortex (S1) of the brain are some of the most consistently reported brain findings in CRPS, the mechanisms are yet to be explored in full, not least of all how these two regions interact and how they might relate to clinical deficits, such as the commonly reported poor tactile acuity in this condition. This study recruited 15 upper‐limb CRPS subjects and 30 healthy controls and used functional magnetic resonance imaging (fMRI) to investigate infra‐slow oscillations (ISOs) in critical pain regions of the brain in CRPS. As hypothesised, we found CRPS was associated with increases in resting signal intensity ISOs (0.03–0.06 Hz) in the thalamus contralateral to the painful limb in CRPS subjects. Interestingly, there was no such difference between groups in S1, however CRPS subjects displayed stronger thalamo‐S1 functional connectivity than controls, and this was related to pain. As predicted, CRPS subjects displayed poor tactile acuity on the painful limb which, interestingly, was also related to thalamo‐S1 functional connectivity strength. Our findings provide novel evidence of altered patterns of resting activity and connectivity in CRPS which may underlie altered thalamocortical loop dynamics and the constant perception of pain.
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Affiliation(s)
- Flavia Di Pietro
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia.,School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, Australia
| | - Barbara Lee
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - Luke A Henderson
- Department of Anatomy and Histology, Brain and Mind Centre, University of Sydney, Sydney, Australia
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22
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Lin C, Yeung AWK. What do we learn from brain imaging?—A primer for the dentists who want to know more about the association between the brain and human stomatognathic functions. J Oral Rehabil 2020; 47:659-671. [DOI: 10.1111/joor.12935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/10/2019] [Accepted: 01/05/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Chia‐shu Lin
- Department of Dentistry School of Dentistry National Yang‐Ming University Taipei Taiwan
- Institute of Brain Science School of Medicine National Yang‐Ming University Taipei Taiwan
- Brain Research Center National Yang‐Ming University Taipei Taiwan
| | - Andy Wai Kan Yeung
- Oral and Maxillofacial Radiology Applied Oral Sciences and Community Dental Care Faculty of Dentistry The University of Hong Kong Hong Kong China
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23
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Doshi TL, Nixdorf DR, Campbell CM, Raja SN. Biomarkers in Temporomandibular Disorder and Trigeminal Neuralgia: A Conceptual Framework for Understanding Chronic Pain. CANADIAN JOURNAL OF PAIN-REVUE CANADIENNE DE LA DOULEUR 2020; 4:1-18. [PMID: 32923920 PMCID: PMC7486013 DOI: 10.1080/24740527.2019.1709163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this review, we will explore the use of biomarkers in chronic pain, using the examples of two prototypical facial pain conditions: trigeminal neuralgia and temporomandibular disorder. We will discuss the main categories of biomarkers and identify various genetic/genomic, molecular, neuroradiological, and psychophysical biomarkers in both facial pain conditions, using them to compare and contrast features of neuropathic, nonneuropathic, and mixed pain. By using two distinct model facial pain conditions to explore pain biomarkers, we aim to familiarize readers with different types of biomarkers currently being studied in chronic pain and explore how these biomarkers may be used to develop new precision medicine approaches to pain diagnosis, prognosis, and management.
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Affiliation(s)
- Tina L Doshi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Donald R Nixdorf
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN, USA
| | - Claudia M Campbell
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
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24
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Brainstem neuroimaging of nociception and pain circuitries. Pain Rep 2019; 4:e745. [PMID: 31579846 PMCID: PMC6727990 DOI: 10.1097/pr9.0000000000000745] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/22/2019] [Accepted: 03/24/2019] [Indexed: 01/09/2023] Open
Abstract
The brainstem is known to be an important brain area for nociception and pain processing, and both relaying and coordinating signaling between the cerebrum, cerebellum, and spinal cord. Although preclinical models of pain have characterized the many roles that brainstem nuclei play in nociceptive processing, the degree to which these circuitries extend to humans is not as well known. Unfortunately, the brainstem is also a very challenging region to evaluate in humans with neuroimaging. The challenges for human brainstem imaging arise from the location of this elongated brain structure, proximity to cardiorespiratory noise sources, and the size of its constituent nuclei. These challenges can require dedicated approaches to brainstem imaging, which should be adopted when study hypotheses are focused on brainstem processing of nociception or modulation of pain perception. In fact, our review will highlight many pain neuroimaging studies that have reported some brainstem involvement in nociceptive processing and chronic pain pathology. However, we note that with recent advances in neuroimaging leading to improved spatial and temporal resolution, more studies are needed that take advantage of data collection and analysis methods focused on the challenges of brainstem neuroimaging.
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25
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Youssef AM, Azqueta-Gavaldon M, Silva KE, Barakat N, Lopez N, Mahmud F, Lebel A, Sethna NF, Zurakowski D, Simons LE, Kraft E, Borsook D. Shifting brain circuits in pain chronicity. Hum Brain Mapp 2019; 40:4381-4396. [PMID: 31298464 DOI: 10.1002/hbm.24709] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/04/2019] [Accepted: 06/11/2019] [Indexed: 11/10/2022] Open
Abstract
The evaluation of brain changes to a specific pain condition in pediatric and adult patients allows for insights into potential mechanisms of pain chronicity and possibly long-term brain changes. Here we focused on the primary somatosensory system (SS) involved in pain processing, namely the ventroposterolateral thalamus (VPL) and the primary somatosensory cortex (SI). We evaluated, using MRI, three specific processes: (a) somatotopy of changes in the SS for different pain origins (viz., foot vs. arm); (b) differences in acute (ankle sprain versus complex regional pain syndrome-CRPS); and (c) differences of the effects of CRPS on SS in pediatric versus adult patients. In all cases, age- and sex-matched individuals were used as controls. Our results suggest a shift in concurrent gray matter density (GMD) and resting functional connectivity strengths (rFC) across pediatric and adult CRPS with (a) differential patterns of GMD (VPL) and rFC (SI) on SS in pediatric vs. adult patterns that are consistent with upper and lower limb somatotopical organization; and (b) widespread GMD alterations in pediatric CRPS from sensory, emotional and descending modulatory processes to more confined sensory-emotional changes in adult CRPS and rFC patterns from sensory-sensory alterations in pediatric populations to a sensory-emotional change in adult populations. These results support the idea that pediatric and adult CRPS are differentially represented and may reflect underlying differences in pain chronification across age groups that may contribute to the well-known differences between child and adult pain vulnerability and resilience.
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Affiliation(s)
- Andrew M Youssef
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Monica Azqueta-Gavaldon
- Department of Orthopedics, Physical Medicine and Rehabilitation, Medical Centre of University of Munich, Munich, Germany.,Interdisciplinary Pain Unit, Medical Centre of University of Munich, Munich, Germany
| | - Katie E Silva
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Nadia Barakat
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Natalia Lopez
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Farah Mahmud
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Alyssa Lebel
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Navil F Sethna
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - David Zurakowski
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Laura E Simons
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
| | - Eduard Kraft
- Department of Orthopedics, Physical Medicine and Rehabilitation, Medical Centre of University of Munich, Munich, Germany.,Interdisciplinary Pain Unit, Medical Centre of University of Munich, Munich, Germany
| | - David Borsook
- Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
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26
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Abstract
Arterial Spin Labeling (ASL) is a perfusion-based functional magnetic resonance imaging technique that uses water in arterial blood as a freely diffusible tracer to measure regional cerebral blood flow (rCBF) noninvasively. To date its application to the study of pain has been relatively limited. Yet, ASL possesses key features that make it uniquely positioned to study pain in certain paradigms. For instance, ASL is sensitive to very slowly fluctuating brain signals (in the order of minutes or longer). This characteristic makes ASL particularly suitable to the evaluation of brain mechanisms of tonic experimental, post-surgical and ongoing/or continuously varying pain in chronic or acute pain conditions (whereas BOLD fMRI is better suited to detect brain responses to short-lasting or phasic/evoked pain). Unlike positron emission tomography or other perfusion techniques, ASL allows the estimation of rCBF without requiring the administration of radioligands or contrast agents. Thus, ASL is well suited for within-subject longitudinal designs (e.g., to study evolution of pain states over time, or of treatment effects in clinical trials). ASL is also highly versatile, allowing for novel paradigms exploring a flexible array of pain states, plus it can be used to simultaneously estimate not only pain-related alterations in perfusion but also functional connectivity. In conclusion, ASL can be successfully applied in pain paradigms that would be either challenging or impossible to implement using other techniques. Particularly when used in concert with other neuroimaging techniques, ASL can be a powerful tool in the pain imager's toolbox.
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27
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Sperry MM, Kartha S, Winkelstein BA, Granquist EJ. Experimental Methods to Inform Diagnostic Approaches for Painful TMJ Osteoarthritis. J Dent Res 2019; 98:388-397. [PMID: 30819041 DOI: 10.1177/0022034519828731] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Temporomandibular joint (TMJ) osteoarthritis (OA) is a degenerative disease of the joint that can produce persistent orofacial pain as well as functional and structural changes to its bone, cartilage, and ligaments. Despite advances in the clinical utility and reliability of the Diagnostic Criteria for Temporomandibular Disorders, clinical tools inadequately predict which patients will develop chronic TMJ pain and degeneration, limiting clinical management. The challenges of managing and treating TMJ OA are due, in part, to a limited understanding of the mechanisms contributing to the development and maintenance of TMJ pain. OA is initiated by multiple factors, including injury, aging, abnormal joint mechanics, and atypical joint shape, which can produce microtrauma, remodeling of joint tissues, and synovial inflammation. TMJ microtrauma and remodeling can increase expression of cytokines, chemokines, and catabolic factors that damage synovial tissues and can activate free nerve endings in the joint. Although studies have separately investigated inflammation-driven orofacial pain, acute activity of the trigeminal nerve, or TMJ tissue degeneration and/or damage, the temporal mechanistic factors leading to chronic TMJ pain are undefined. Limited understanding of the interaction between degeneration, intra-articular chemical factors, and pain has further restricted the development of targeted, disease-modifying drugs to help patients avoid long-term pain and invasive procedures, like TMJ replacement. A range of animal models captures features of intra-articular inflammation, joint overloading, and tissue damage. Although those models traditionally measure peripheral sensitivity as a surrogate for pain, recent studies recognize the brain's role in integrating, modulating, and interpreting nociceptive inputs in the TMJ, particularly in light of psychosocial influences on TMJ pain. The articular and neural contributors to TMJ pain, imaging modalities with clinical potential to identify TMJ OA early, and future directions for clinical management of TMJ OA are reviewed in the context of evidence in the field.
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Affiliation(s)
- M M Sperry
- 1 Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - S Kartha
- 1 Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - B A Winkelstein
- 1 Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- 2 Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
| | - E J Granquist
- 3 Oral & Maxillofacial Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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28
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Sclocco R, Garcia RG, Kettner NW, Isenburg K, Fisher HP, Hubbard CS, Ay I, Polimeni JR, Goldstein J, Makris N, Toschi N, Barbieri R, Napadow V. The influence of respiration on brainstem and cardiovagal response to auricular vagus nerve stimulation: A multimodal ultrahigh-field (7T) fMRI study. Brain Stimul 2019; 12:911-921. [PMID: 30803865 DOI: 10.1016/j.brs.2019.02.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/02/2019] [Accepted: 02/06/2019] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Brainstem-focused mechanisms supporting transcutaneous auricular VNS (taVNS) effects are not well understood, particularly in humans. We employed ultrahigh field (7T) fMRI and evaluated the influence of respiratory phase for optimal targeting, applying our respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) technique. HYPOTHESIS We proposed that targeting of nucleus tractus solitarii (NTS) and cardiovagal modulation in response to taVNS stimuli would be enhanced when stimulation is delivered during a more receptive state, i.e. exhalation. METHODS Brainstem fMRI response to auricular taVNS (cymba conchae) was assessed for stimulation delivered during exhalation (eRAVANS) or inhalation (iRAVANS), while exhalation-gated stimulation over the greater auricular nerve (GANctrl, i.e. earlobe) was included as control. Furthermore, we evaluated cardiovagal response to stimulation by calculating instantaneous HF-HRV from cardiac data recorded during fMRI. RESULTS Our findings demonstrated that eRAVANS evoked fMRI signal increase in ipsilateral pontomedullary junction in a cluster including purported NTS. Brainstem response to GANctrl localized a partially-overlapping cluster, more ventrolateral, consistent with spinal trigeminal nucleus. A region-of-interest analysis also found eRAVANS activation in monoaminergic source nuclei including locus coeruleus (LC, noradrenergic) and both dorsal and median raphe (serotonergic) nuclei. Response to eRAVANS was significantly greater than iRAVANS for all nuclei, and greater than GANctrl in LC and raphe nuclei. Furthermore, eRAVANS, but not iRAVANS, enhanced cardiovagal modulation, confirming enhanced eRAVANS response on both central and peripheral neurophysiological levels. CONCLUSION 7T fMRI localized brainstem response to taVNS, linked such response with autonomic outflow, and demonstrated that taVNS applied during exhalation enhanced NTS targeting.
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Affiliation(s)
- Roberta Sclocco
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Radiology, Logan University, Chesterfield, MO, USA.
| | - Ronald G Garcia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Norman W Kettner
- Department of Radiology, Logan University, Chesterfield, MO, USA
| | - Kylie Isenburg
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Harrison P Fisher
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Catherine S Hubbard
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Ilknur Ay
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jonathan R Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jill Goldstein
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Department of Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nikos Makris
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicola Toschi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Riccardo Barbieri
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy; Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Vitaly Napadow
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; Department of Radiology, Logan University, Chesterfield, MO, USA
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29
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Grading facial expression is a sensitive means to detect grimace differences in orofacial pain in a rat model. Sci Rep 2018; 8:13894. [PMID: 30224708 PMCID: PMC6141616 DOI: 10.1038/s41598-018-32297-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/31/2018] [Indexed: 12/17/2022] Open
Abstract
Although pre-clinical models of pain are useful for defining relationships between biological mechanisms and pain, common methods testing peripheral sensitivity do not translate to the human pain experience. Facial grimace scales evaluate affective pain levels in rodent models by capturing and scoring spontaneous facial expression. But, the Rat Grimace Scale (RGS) has not assessed the common disorder of temporomandibular joint (TMJ) pain. A rat model of TMJ pain induced by jaw loading (1 hr/day for 7 days) was used to investigate the time course of RGS scores and compare them between different loading magnitudes with distinct peripheral sensitivity profiles (0N–no sensitivity, 2N–acute sensitivity, 3.5N–persistent sensitivity). In the 3.5N group, RGS is elevated over baseline during the loading period and one day after loading and is correlated with peripheral sensitivity (ρ = −0.48, p = 0.002). However, RGS is not elevated later when that group exhibits peripheral sensitivity and moderate TMJ condylar cartilage degeneration. Acutely, RGS is elevated in the 3.5N loading group over the other loading groups (p < 0.001). These findings suggest that RGS is an effective tool for detecting spontaneous TMJ pain and that spontaneous pain is detectable in rats that develop persistent TMJ sensitivity, but not in rats with acute resolving sensitivity.
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30
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Acute and Chronic Pain Processing in the Thalamocortical System of Humans and Animal Models. Neuroscience 2018; 387:58-71. [DOI: 10.1016/j.neuroscience.2017.09.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/24/2017] [Accepted: 09/24/2017] [Indexed: 02/07/2023]
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31
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Braunsteiner NE, Vickers ER, Toole BM, Braunsteiner J. Psychosocial factors and addiction in chronic orofacial neuropathic pain. AUST ENDOD J 2018. [DOI: 10.1111/aej.12254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Natasha E. Braunsteiner
- Olympus Health Group; Sydney New South Wales Australia
- University of Queensland Dental School; Brisbane Queensland Australia
| | - E. Russell Vickers
- Olympus Health Group; Sydney New South Wales Australia
- University of Queensland Dental School; Brisbane Queensland Australia
- University of Sydney Medical School; Sydney New South Wales Australia
- Clinical Stem Cells Pty Ltd; Sydney New South Wales Australia
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32
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Henderson LA. Trigeminal neuropathic pain: Evidence of central changes from human brain imaging investigations. AUST ENDOD J 2018. [DOI: 10.1111/aej.12250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luke A. Henderson
- Department of Anatomy and Histology; University of Sydney; Sydney New South Wales Australia
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Zhang J, Li X, Jin Z, Liang M, Ma X. Spontaneous brain activity and connectivity in female patients with temporomandibular joint synovitis pain: a pilot functional magnetic resonance imaging study. Oral Surg Oral Med Oral Pathol Oral Radiol 2018; 126:363-374. [PMID: 30037632 DOI: 10.1016/j.oooo.2018.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/16/2018] [Accepted: 04/06/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVE It has been proposed that mechanisms in the central nervous system contribute to the development and maintenance of pain in temporomandibular disorders. In this study, we tested whether spontaneous brain activity and functional connectivity (FC) were altered in patients with temporomandibular joint synovitis pain. STUDY DESIGN A prospective, cross-sectional design was adopted. Each of 8 patients and 10 healthy controls (HCs) underwent 2 sessions of functional magnetic resonance imaging: mouth closed and mouth open (painful for patients). Regional homogeneity (ReHo) was used to measure spontaneous brain activity in each participant. Brain areas with altered ReHo in patients compared with HCs were identified, and their FCs with the rest of the brain was examined and compared. RESULTS Compared with HCs, patients showed decreased pain-related ReHo in the right anterior insula (rAI). The rAI showed a weaker positive FC with the left middle cingulate cortex (MCC) and a weaker negative FC with the right precuneus in patients compared with HCs. Furthermore, the rAI-MCC FC showed a negative correlation with pain intensity in patients. CONCLUSIONS These results provide evidence supporting altered pain-related spontaneous brain activity and functional connectivity in the central nervous system in patients with temporomandibular joint synovitis pain.
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Affiliation(s)
- Juan Zhang
- Center for Temporomandibular Joint Disorder and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing, China; Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
| | - Xin Li
- Department of Prosthodontics, Tianjin Medical University School and Hospital of Stomatology, Tianjin, China
| | - Zhen Jin
- Department of Radiology, 306 Hospital of People's Liberation Army, Beijing, China
| | - Meng Liang
- School of Medical Imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin, China.
| | - Xuchen Ma
- Center for Temporomandibular Joint Disorder and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing, China.
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Alshelh Z, Di Pietro F, Mills EP, Vickers ER, Peck CC, Murray GM, Henderson LA. Altered regional brain T2 relaxation times in individuals with chronic orofacial neuropathic pain. NEUROIMAGE-CLINICAL 2018; 19:167-173. [PMID: 30035014 PMCID: PMC6051476 DOI: 10.1016/j.nicl.2018.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/10/2018] [Accepted: 04/12/2018] [Indexed: 01/12/2023]
Abstract
The neural mechanisms underlying the development and maintenance of chronic pain following nerve injury remain unclear. There is growing evidence that chronic neuropathic pain is associated with altered thalamic firing patterns, thalamocortical dysrhythmia and altered infra-slow oscillations in ascending pain pathways. Preclinical and post-mortem human studies have revealed that neuropathic pain is associated with prolonged astrocyte activation in the dorsal horn and we have suggested that this may result in altered gliotransmission, which results in altered resting neural rhythm in the ascending pain pathway. Evidence of astrocyte activation above the level of the dorsal horn in living humans is lacking and direct measurement of astrocyte activation in living humans is not possible, however, there is evidence that regional alterations in T2 relaxation times are indicative of astrogliosis. The aim of this study was to use T2 relaxometry to explore regional brain anatomy of the ascending pain pathway in individuals with chronic orofacial neuropathic pain. We found that in individuals with trigeminal neuropathic pain, decreases in T2 relaxation times occurred in the region of the spinal trigeminal nucleus and primary somatosensory cortex, as well as in higher order processing regions such as the dorsolateral prefrontal, cingulate and hippocampal/parahippocampal cortices. We speculate that these regional changes in T2 relaxation times reflect prolonged astrocyte activation, which results in altered brain rhythm and ultimately the constant perception of pain. Blocking prolonged astrocyte activation may be effective in preventing and even reversing the development of chronic pain following neural injury. Reduced T2 relaxation time in the ascending pain pathway in chronic orofacial pain. These reductions may be associated with astrogliosis. Increase astrocyte activity associated with chronic orofacial pain.
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Affiliation(s)
- Z Alshelh
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, 2006, Australia
| | - F Di Pietro
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, 2006, Australia
| | - E P Mills
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, 2006, Australia
| | - E R Vickers
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, 2006, Australia
| | - C C Peck
- Faculty of Dentistry, University of Sydney, 2006, Australia
| | - G M Murray
- Faculty of Dentistry, University of Sydney, 2006, Australia
| | - L A Henderson
- Department of Anatomy and Histology, Sydney Medical School, University of Sydney, 2006, Australia.
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Sperry MM, Ita ME, Kartha S, Zhang S, Yu YH, Winkelstein B. The Interface of Mechanics and Nociception in Joint Pathophysiology: Insights From the Facet and Temporomandibular Joints. J Biomech Eng 2017; 139:2597611. [PMID: 28056123 DOI: 10.1115/1.4035647] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Indexed: 12/16/2022]
Abstract
Chronic joint pain is a widespread problem that frequently occurs with aging and trauma. Pain occurs most often in synovial joints, the body's load bearing joints. The mechanical and molecular mechanisms contributing to synovial joint pain are reviewed using two examples, the cervical spinal facet joints and the temporomandibular joint (TMJ). Although much work has focused on the macroscale mechanics of joints in health and disease, the combined influence of tissue mechanics, molecular processes, and nociception in joint pain has only recently become a focus. Trauma and repeated loading can induce structural and biochemical changes in joints, altering their microenvironment and modifying the biomechanics of their constitutive tissues, which themselves are innervated. Peripheral pain sensors can become activated in response to changes in the joint microenvironment and relay pain signals to the spinal cord and brain where pain is processed and perceived. In some cases, pain circuitry is permanently changed, which may be a potential mechanism for sustained joint pain. However, it is most likely that alterations in both the joint microenvironment and the central nervous system (CNS) contribute to chronic pain. As such, the challenge of treating joint pain and degeneration is temporally and spatially complicated. This review summarizes anatomy, physiology, and pathophysiology of these joints and the sensory pain relays. Pain pathways are postulated to be sensitized by many factors, including degeneration and biochemical priming, with effects on thresholds for mechanical injury and/or dysfunction. Initiators of joint pain are discussed in the context of clinical challenges including the diagnosis and treatment of pain.
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Affiliation(s)
- Megan M Sperry
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Meagan E Ita
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Sonia Kartha
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Sijia Zhang
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Ya-Hsin Yu
- Department of Endodontics, School of Dental Medicine, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Beth Winkelstein
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
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Tsai YH, Yuan R, Patel D, Chandrasekaran S, Weng HH, Yang JT, Lin CP, Biswal BB. Altered structure and functional connection in patients with classical trigeminal neuralgia. Hum Brain Mapp 2017; 39:609-621. [PMID: 29105886 DOI: 10.1002/hbm.23696] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/10/2017] [Accepted: 06/13/2017] [Indexed: 12/26/2022] Open
Abstract
Classical trigeminal neuralgia (TN) is a specific type of neuropathic orofacial pain of which the plasticity of brain structure and connectivity have remained largely unknown. A total of 62 TN patients were included and referred to MRI scans. Voxel-based morphometry was used to analyze the change of gray matter volume. Resting-state functional imaging was used to analyze the connectivity between brain regions. The results showed gray matter volume reduction in components of the prefrontal cortex, precentral gyrus, cerebellar tonsil, thalamus, hypothalamus, and nucleus accumbens among right TN patient and in the inferior frontal gyrus, precentral gyrus, cerebellum, thalamus, ventral striatum, and putamen among left TN patients. The connections between the right superior frontal gyrus and right middle frontal gyrus were lower in right TN patients. The connection between the left precentral gyrus and the left superior frontal gyrus was lower while the connection between bilateral thalamus was higher in left TN patients. The changes of volume in bilateral thalamus of right TN patients and left ventral striatum of left TN patients, and the connectivity between bilateral thalamus of left TN patients were moderately correlated with pain duration. These findings suggest that brain regions such as the thalamus may not only be involved in processing of pain stimuli but also be important for the development of TN. The left hemisphere may be dominant in processing and modulation of TN pain signal. Chronification of TN induces volume changes in brain regions which are associated with emotional or cognitive modulation of pain. Hum Brain Mapp 39:609-621, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yuan-Hsiung Tsai
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital at Chiayi, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Rui Yuan
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey
| | - Dharni Patel
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey
| | - Subhashini Chandrasekaran
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey
| | - Hsu-Huei Weng
- Department of Diagnostic Radiology, Chang Gung Memorial Hospital at Chiayi, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Jen-Tsung Yang
- Department of Neurosurgery, Chang Gung Memorial Hospital at Chiayi, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming University, Taipei, Taiwan
| | - Bharat B Biswal
- Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey
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Alshelh Z, Marciszewski KK, Akhter R, Di Pietro F, Mills EP, Vickers ER, Peck CC, Murray GM, Henderson LA. Disruption of default mode network dynamics in acute and chronic pain states. NEUROIMAGE-CLINICAL 2017; 17:222-231. [PMID: 29159039 PMCID: PMC5683191 DOI: 10.1016/j.nicl.2017.10.019] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/08/2017] [Accepted: 10/18/2017] [Indexed: 12/21/2022]
Abstract
It has been proposed that pain competes with other attention-demanding stimuli for cognitive resources, and many chronic pain patients display significant attention and mental flexibility deficits. These alterations may result from disruptions in the functioning of the default mode network (DMN) which plays a critical role in attention, memory, prospection and self-processing, and recent investigations have found alterations in DMN function in multiple chronic pain conditions. Whilst it has been proposed that these DMN alterations are a characteristic of pain that is chronic in nature, we recently reported altered oscillatory activity in the DMN during an acute, 5 minute noxious stimulus in healthy control subjects. We therefore hypothesize that altered DMN activity patterns will not be restricted to those in chronic pain but instead will also occur in healthy individuals during tonic noxious stimuli. We used functional magnetic resonance imaging to measure resting state infra-slow oscillatory activity and functional connectivity in patients with chronic orofacial pain at rest and in healthy controls during a 20-minute tonic pain stimulus. We found decreases in oscillatory activity in key regions of the DMN in patients with chronic pain, as well as in healthy controls during tonic pain in addition to changes in functional connectivity between the posterior cingulate cortex and areas of the DMN in both groups. The results show that similar alterations in DMN function occur in healthy individuals during acute noxious stimuli as well as in individuals with chronic pain. These DMN changes may reflect the presence of pain per se and may underlie alterations in attentional processes that occur in the presence of pain. Default mode network dynamics were measured in chronic and acute pain. Altered infra-slow activity and connectivity occurred in chronic and acute pain. Default mode network changes characterize pain per se.
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Affiliation(s)
- Z Alshelh
- Department of Anatomy and Histology, University of Sydney, 2006, Australia
| | - K K Marciszewski
- Department of Anatomy and Histology, University of Sydney, 2006, Australia
| | - R Akhter
- Faculty of Dentistry, University of Sydney, 2006, Australia
| | - F Di Pietro
- Department of Anatomy and Histology, University of Sydney, 2006, Australia
| | - E P Mills
- Department of Anatomy and Histology, University of Sydney, 2006, Australia
| | - E R Vickers
- Department of Anatomy and Histology, University of Sydney, 2006, Australia
| | - C C Peck
- Faculty of Dentistry, University of Sydney, 2006, Australia
| | - G M Murray
- Faculty of Dentistry, University of Sydney, 2006, Australia
| | - L A Henderson
- Department of Anatomy and Histology, University of Sydney, 2006, Australia.
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Seminowicz DA, Moayedi M. The Dorsolateral Prefrontal Cortex in Acute and Chronic Pain. THE JOURNAL OF PAIN 2017; 18:1027-1035. [PMID: 28400293 PMCID: PMC5581265 DOI: 10.1016/j.jpain.2017.03.008] [Citation(s) in RCA: 250] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/15/2017] [Accepted: 03/20/2017] [Indexed: 02/06/2023]
Abstract
The dorsolateral prefrontal cortex (DLPFC) is a functionally and structurally heterogeneous region and a key node of several brain networks, implicated in cognitive, affective, and sensory processing. As such, the DLPFC is commonly activated in experimental pain studies, and shows abnormally increased function in chronic pain populations. Furthermore, several studies have shown that some chronic pains are associated with decreased left DLPFC gray matter and that successful interventions can reverse this structural abnormality. In addition, studies have indicated that noninvasive stimulation of the left DLPFC effectively treats some chronic pains. In this article, we review the neuroimaging literature regarding the role of the DLPFC and its potential as a therapeutic target for chronic pain conditions, including studies showing the involvement of the DLPFC in encoding and modulating acute pain and studies demonstrating the reversal of DLPFC functional and structural abnormalities after successful interventions for chronic pain. We also review studies of noninvasive brain stimulation of the DLPFC showing acute pain modulation and some effectiveness as a treatment for certain chronic pain conditions. We further discuss the network architecture of the DLPFC, and postulate mechanisms by which DLPFC stimulation alleviates chronic pain. Future work testing these mechanisms will allow for more effective therapies. PERSPECTIVE The structure and function of the DLPFC is abnormal in some chronic pain conditions. Upon successful resolution of pain, these abnormalities are reversed. Understanding the underlying mechanisms and the role of this region can lead to the development of an effective therapeutic target for some chronic pain conditions.
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Affiliation(s)
- David A Seminowicz
- Department of Neural and Pain Sciences, University of Maryland, School of Dentistry, Baltimore, Maryland; Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, Maryland.
| | - Massieh Moayedi
- Faculty of Dentistry, and University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, Ontario, Canada
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39
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Henderson LA, Keay KA. Imaging Acute and Chronic Pain in the Human Brainstem and Spinal Cord. Neuroscientist 2017; 24:84-96. [PMID: 28447501 DOI: 10.1177/1073858417703911] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
While acute pain serves as a protective mechanism designed to warn an individual of potential or actual damaging stimuli, chronic pain provides no benefit and is now considered a disease in its own right. Since the advent of human brain imaging techniques, many investigations that have explored the central representation of acute and chronic pain have focused on changes in higher order brain regions. In contrast, far fewer have explored brainstem and spinal cord function, mainly due to significant technical difficulties. In this review, we present some of the recent human brain imaging studies that have specifically explored brainstem and spinal cord function during acute noxious stimuli and in individuals with chronic pain. We focus particularly on investigations that explore changes in areas that receive nociceptor afferents and compare humans and experimental animal data in an attempt to describe both microscopic and macroscopic changes associated with acute and chronic pain.
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Affiliation(s)
- Luke A Henderson
- 1 Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia
| | - Kevin A Keay
- 1 Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia
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40
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Sclocco R, Beissner F, Bianciardi M, Polimeni JR, Napadow V. Challenges and opportunities for brainstem neuroimaging with ultrahigh field MRI. Neuroimage 2017; 168:412-426. [PMID: 28232189 DOI: 10.1016/j.neuroimage.2017.02.052] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/30/2017] [Accepted: 02/19/2017] [Indexed: 12/19/2022] Open
Abstract
The human brainstem plays a central role in connecting the cerebrum, the cerebellum and the spinal cord to one another, hosting relay nuclei for afferent and efferent signaling, and providing source nuclei for several neuromodulatory systems that impact central nervous system function. While the investigation of the brainstem with functional or structural magnetic resonance imaging has been hampered for years due to this brain structure's physiological and anatomical characteristics, the field has seen significant advances in recent years thanks to the broader adoption of ultrahigh-field (UHF) MRI scanning. In the present review, we focus on the advantages offered by UHF in the context of brainstem imaging, as well as the challenges posed by the investigation of this complex brain structure in terms of data acquisition and analysis. We also illustrate how UHF MRI can shed new light on the neuroanatomy and neurophysiology underlying different brainstem-based circuitries, such as the central autonomic network and neurotransmitter/neuromodulator systems, discuss existing and foreseeable clinical applications to better understand diseases such as chronic pain and Parkinson's disease, and explore promising future directions for further improvements in brainstem imaging using UHF MRI techniques.
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Affiliation(s)
- Roberta Sclocco
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, CNY 149-2301, 13th St. Charlestown, Boston, MA 02129, USA; Department of Radiology, Logan University, Chesterfield, MO, USA.
| | - Florian Beissner
- Somatosensory and Autonomic Therapy Research, Institute for Neuroradiology, Hannover Medical School, Hannover, Germany
| | - Marta Bianciardi
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, CNY 149-2301, 13th St. Charlestown, Boston, MA 02129, USA
| | - Jonathan R Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, CNY 149-2301, 13th St. Charlestown, Boston, MA 02129, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Vitaly Napadow
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, CNY 149-2301, 13th St. Charlestown, Boston, MA 02129, USA; Department of Radiology, Logan University, Chesterfield, MO, USA
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Avivi-Arber L, Seltzer Z, Friedel M, Lerch JP, Moayedi M, Davis KD, Sessle BJ. Widespread Volumetric Brain Changes following Tooth Loss in Female Mice. Front Neuroanat 2017; 10:121. [PMID: 28119577 PMCID: PMC5220047 DOI: 10.3389/fnana.2016.00121] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/01/2016] [Indexed: 12/19/2022] Open
Abstract
Tooth loss is associated with altered sensory, motor, cognitive and emotional functions. These changes vary highly in the population and are accompanied by structural and functional changes in brain regions mediating these functions. It is unclear to what extent this variability in behavior and function is caused by genetic and/or environmental determinants and which brain regions undergo structural plasticity that mediates these changes. Thus, the overall goal of our research program is to identify genetic variants that control structural and functional plasticity following tooth loss. As a step toward this goal, here our aim was to determine whether structural magnetic resonance imaging (sMRI) is sensitive to detect quantifiable volumetric differences in the brains of mice of different genetic background receiving tooth extraction or sham operation. We used 67 adult female mice of 7 strains, comprising the A/J (A) and C57BL/6J (B) strains and a randomly selected sample of 5 of the 23 AXB-BXA strains (AXB1, AXB4, AXB24, BXA14, BXA24) that were produced from the A and B parental mice by recombinations and inbreeding. This panel of 25 inbred strains of genetically diverse inbred strains of mice is used for mapping chromosomal intervals throughout the genome that harbor candidate genes controlling the phenotypic variance of any trait under study. Under general anesthesia, 39 mice received extraction of 3 right maxillary molar teeth and 28 mice received sham operation. On post-extraction day 21, post-mortem whole-brain high-resolution sMRI was used to quantify the volume of 160 brain regions. Compared to sham operation, tooth extraction was associated with a significantly reduced regional and voxel-wise volumes of cortical brain regions involved in processing somatosensory, motor, cognitive and emotional functions, and increased volumes in subcortical sensorimotor and temporal limbic forebrain regions including the amygdala. Additionally, comparison of the 10 BXA14 and 21 BXA24 mice revealed significant volumetric differences between the two strains in several brain regions. These findings highlight the utility of high-resolution sMRI for studying tooth loss-induced structural brain plasticity in mice, and provide a foundation for further phenotyping structural brain changes following tooth loss in the full AXB-BXA panel to facilitate mapping genes that control brain plasticity following orofacial injury.
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Affiliation(s)
- Limor Avivi-Arber
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
| | - Ze'ev Seltzer
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
- Department of Anesthesiology, University Health NetworkToronto, ON, Canada
- Central Institute of Mental Health, University of HeidelbergMannheim, Germany
| | - Miriam Friedel
- Mouse Imaging Centre, Hospital for Sick ChildrenToronto, ON, Canada
| | - Jason P. Lerch
- Mouse Imaging Centre, Hospital for Sick ChildrenToronto, ON, Canada
- Medical Biophysics, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - Massieh Moayedi
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
| | - Karen D. Davis
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Department of Surgery, University of TorontoToronto, ON, Canada
- Institute of Medical Science, University of TorontoToronto, ON, Canada
- Division of Brain, Imaging and Behaviour - Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health NetworkToronto, ON, Canada
| | - Barry J. Sessle
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
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Walitt B, Ceko M, Gracely JL, Gracely RH. Neuroimaging of Central Sensitivity Syndromes: Key Insights from the Scientific Literature. Curr Rheumatol Rev 2016; 12:55-87. [PMID: 26717948 DOI: 10.2174/1573397112666151231111104] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/24/2015] [Accepted: 12/29/2015] [Indexed: 12/14/2022]
Abstract
Central sensitivity syndromes are characterized by distressing symptoms, such as pain and fatigue, in the absence of clinically obvious pathology. The scientific underpinnings of these disorders are not currently known. Modern neuroimaging techniques promise new insights into mechanisms mediating these postulated syndromes. We review the results of neuroimaging applied to five central sensitivity syndromes: fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular joint disorder, and vulvodynia syndrome. Neuroimaging studies of basal metabolism, anatomic constitution, molecular constituents, evoked neural activity, and treatment effect are compared across all of these syndromes. Evoked sensory paradigms reveal sensory augmentation to both painful and nonpainful stimulation. This is a transformative observation for these syndromes, which were historically considered to be completely of hysterical or feigned in origin. However, whether sensory augmentation represents the cause of these syndromes, a predisposing factor, an endophenotype, or an epiphenomenon cannot be discerned from the current literature. Further, the result from cross-sectional neuroimaging studies of basal activity, anatomy, and molecular constituency are extremely heterogeneous within and between the syndromes. A defining neuroimaging "signature" cannot be discerned for any of the particular syndromes or for an over-arching central sensitization mechanism common to all of the syndromes. Several issues confound initial attempts to meaningfully measure treatment effects in these syndromes. At this time, the existence of "central sensitivity syndromes" is based more soundly on clinical and epidemiological evidence. A coherent picture of a "central sensitization" mechanism that bridges across all of these syndromes does not emerge from the existing scientific evidence.
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Affiliation(s)
- Brian Walitt
- National Center for Complementary and Integrative Health, National Institutes of Health, 10 Center Drive, Bethesda, MD 20814, USA.
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Parker RS, Lewis GN, Rice DA, McNair PJ. Is Motor Cortical Excitability Altered in People with Chronic Pain? A Systematic Review and Meta-Analysis. Brain Stimul 2016; 9:488-500. [DOI: 10.1016/j.brs.2016.03.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/02/2016] [Accepted: 03/30/2016] [Indexed: 01/18/2023] Open
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Basal Ganglia Perfusion in Fibromyalgia is Related to Pain Disability and Disease Impact. Clin J Pain 2016; 32:495-505. [DOI: 10.1097/ajp.0000000000000295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Abstract
The neural mechanisms underlying the development and maintenance of chronic neuropathic pain remain unclear. Evidence from human investigations suggests that neuropathic pain is associated with altered thalamic burst firing and thalamocortical dysrhythmia. Additionally, experimental animal investigations show that neuropathic pain is associated with altered infra-slow (<0.1 Hz) frequency oscillations within the dorsal horn and somatosensory thalamus. The aim of this investigation was to determine whether, in humans, neuropathic pain was also associated with altered infra-slow oscillations within the ascending "pain" pathway. Using resting-state functional magnetic resonance imaging, we found that individuals with orofacial neuropathic pain have increased infra-slow oscillatory activity throughout the ascending pain pathway, including within the spinal trigeminal nucleus, somatosensory thalamus, thalamic reticular nucleus, and primary somatosensory cortex. Furthermore, these infra-slow oscillations were temporally coupled across these multiple sites and occurred at frequencies similar to calcium waves in activated astrocytes. The region encompassing the spinal trigeminal nucleus also displayed increased regional homogeneity, consistent with a local spread of neural activity by astrocyte activation. In contrast, no increase in oscillatory behavior within the ascending pain pathway occurred during acute noxious stimuli in healthy individuals. These data reveal increased oscillatory activity within the ascending pain pathway that likely underpins increased thalamocortical oscillatory activity, a self-sustaining thalamocortical dysrhythmia, and the constant perception of pain. Significance statement: Chronic neuropathic pain is associated with altered thalamic firing and thalamocortical dysrhythmia. The mechanisms responsible for these changes remain unknown. In this study, we report in individuals with neuropathic pain increased oscillatory neural activity within the ascending pain pathway with evidence that these changes result from altered neural-astrocyte coupling. We propose a series of neural and glial events after nerve injury that result in the generation of altered thalamocortical activity and a persistent neuropathic pain state. Defining the underlying mechanisms responsible for neuropathic pain is critical if we are to develop more effective treatment regimens.
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Youssef AM, Macefield VG, Henderson LA. Cortical influences on brainstem circuitry responsible for conditioned pain modulation in humans. Hum Brain Mapp 2016; 37:2630-44. [PMID: 27104478 DOI: 10.1002/hbm.23199] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/25/2016] [Accepted: 03/18/2016] [Indexed: 11/07/2022] Open
Abstract
Conditioned pain modulation (CPM) is a powerful endogenous analgesic mechanism which can completely inhibit incoming nociceptor signals at the primary synapse. The circuitry responsible for CPM lies within the brainstem and involves the subnucleus reticularis dorsalis (SRD). While the brainstem is critical for CPM, the cortex can significantly modulate its expression, likely via the brainstem circuitry critical for CPM. Since higher cortical regions such as the anterior, mid-cingulate, and dorsolateral prefrontal cortices are activated by noxious stimuli and show reduced activations during other analgesic responses, we hypothesized that these regions would display reduced responses during CPM analgesia. Furthermore, we hypothesized that functional connectivity strength between these cortical regions and the SRD would be stronger in those that express CPM analgesia compared with those that do not. We used functional magnetic resonance imaging to determine sites recruited during CPM expression and their influence on the SRD. A lack of CPM analgesia was associated with greater signal intensity increases during each test stimulus in the presence of the conditioning stimulus compared to test stimuli alone in the mid-cingulate and dorsolateral prefrontal cortices and increased functional connectivity with the SRD. In contrast, those subjects exhibiting CPM analgesia showed no change in the magnitude of signal intensity increases in these cortical regions or strength of functional connectivity with the SRD. These data suggest that during multiple or widespread painful stimuli, engagement of the prefrontal and cingulate cortices prevents the generation of CPM analgesia, raising the possibility altered responsiveness in these cortical regions underlie the reduced CPM observed in individuals with chronic pain. Hum Brain Mapp 37:2630-2644, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Andrew M Youssef
- Department of Anatomy and Histology, University of Sydney, Sydney, 2006, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia
- Neuroscience Research Australia, Sydney, Australia
| | - Luke A Henderson
- Department of Anatomy and Histology, University of Sydney, Sydney, 2006, Australia
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Henderson LA, Di Pietro F. How do neuroanatomical changes in individuals with chronic pain result in the constant perception of pain? Pain Manag 2016; 6:147-59. [PMID: 26997246 DOI: 10.2217/pmt.15.67] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Since the advent of anatomical brain imaging analysis techniques, numerous reports have shown altered regional brain anatomy in individuals with various chronic pain conditions. While early reports of increased regional brain volumes in taxi drivers and pianists were simply interpreted as responses to excessive use, the mechanisms responsible for anatomical changes associated with chronic pain are not so straightforward. The main aim of this paper is to explore the potential underlying cellular changes responsible for change in gross brain anatomy in individuals with chronic pain, in particular pain following nervous system damage. Determining the basis of these changes may provide a platform for development of targeted, personalized and ultimately more effective treatment regimens.
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Affiliation(s)
- Luke A Henderson
- Department of Anatomy & Histology, F13, University of Sydney, Sydney, Australia
| | - Flavia Di Pietro
- Department of Anatomy & Histology, F13, University of Sydney, Sydney, Australia
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Lim M, Kim JS, Kim DJ, Chung CK. Increased Low- and High-Frequency Oscillatory Activity in the Prefrontal Cortex of Fibromyalgia Patients. Front Hum Neurosci 2016; 10:111. [PMID: 27014041 PMCID: PMC4789463 DOI: 10.3389/fnhum.2016.00111] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/29/2016] [Indexed: 11/30/2022] Open
Abstract
Recent human neuroimaging studies have suggested that fibromyalgia (FM), a chronic widespread pain disorder, exhibits altered thalamic structure and function. Since the thalamus has extensive reciprocal connection with the cortex, structural and functional thalamic alterations in FM might be linked to aberrant thalamocortical oscillation. This study investigated the presence of abnormal brain rhythmicity in low- and high-frequency bands during resting state in patients with FM and their relationship to clinical pain symptom. Spontaneous magnetoencephalography (MEG) activity was recorded in 18 females with FM and 18 age- and sex-matched healthy control (HC) subjects. The most remarkable finding was that FM patients had general increases in theta, beta and gamma power along with a slowing of the dominant alpha peak. Increased spectral powers in the theta-band were primarily localized to the left dorsolateral prefrontal (DLPFC) and orbitofrontal cortex (OFC). Beta and gamma over-activation were localized to insular, primary motor and primary and secondary somatosensory (S2) cortices, as well as the DLPFC and OFC. Furthermore, enhanced high-frequency oscillatory activities in the DLPFC and OFC were associated with higher affective pain scores in patients with FM. Our results demonstrate that FM patients feature enhanced low- and high-frequency oscillatory activity in the brain areas related to cognitive and emotional modulation of pain. Increased low- and high-frequency activity of the prefrontal cortex may contribute to persistent perception of pain in FM. Therapeutic intervention based on manipulating neural oscillation to restore normal thalamocortical rhythmicity may be beneficial to pain relief in FM.
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Affiliation(s)
- Manyoel Lim
- Neuroscience Research Institute, Seoul National University College of Medicine Seoul, South Korea
| | - June Sic Kim
- Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences Seoul, South Korea
| | - Dajung J Kim
- Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences Seoul, South Korea
| | - Chun Kee Chung
- Neuroscience Research Institute, Seoul National University College of MedicineSeoul, South Korea; Department of Brain and Cognitive Sciences, Seoul National University College of Natural SciencesSeoul, South Korea; Department of Neurosurgery, Seoul National University HospitalSeoul, South Korea
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Pathophysiological implication of CaV3.1 T-type Ca2+ channels in trigeminal neuropathic pain. Proc Natl Acad Sci U S A 2016; 113:2270-5. [PMID: 26858455 DOI: 10.1073/pnas.1600418113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A crucial pathophysiological issue concerning central neuropathic pain is the modification of sensory processing by abnormally increased low-frequency brain rhythms. Here we explore the molecular mechanisms responsible for such abnormal rhythmicity and its relation to neuropathic pain syndrome. Toward this aim, we investigated the behavioral and electrophysiological consequences of trigeminal neuropathic pain following infraorbital nerve ligations in CaV3.1 T-type Ca(2+) channel knockout and wild-type mice. CaV3.1 knockout mice had decreased mechanical hypersensitivity and reduced low-frequency rhythms in the primary somatosensory cortex and related thalamic nuclei than wild-type mice. Lateral inhibition of gamma rhythm in primary somatosensory cortex layer 4, reflecting intact sensory contrast, was present in knockout mice but severely impaired in wild-type mice. Moreover, cross-frequency coupling between low-frequency and gamma rhythms, which may serve in sensory processing, was pronounced in wild-type mice but not in CaV3.1 knockout mice. Our results suggest that the presence of CaV3.1 channels is a key element in the pathophysiology of trigeminal neuropathic pain.
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Moana-Filho EJ, Bereiter DA, Nixdorf DR. Amplified Brain Processing of Dentoalveolar Pressure Stimulus in Persistent Dentoalveolar Pain Disorder Patients. J Oral Facial Pain Headache 2016; 29:349-62. [PMID: 26485382 DOI: 10.11607/ofph.1463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS (1) To determine the brain regions activated by dentoalveolar pressure stimulation in persistent dentoalveolar pain disorder (PDAP) patients, and (2) to compare these activation patterns to those seen in pain-free control subjects. METHODS A total of 13 PDAP patients and 13 matched controls completed the study. Clinical pain characteristics and psychosocial data were collected. Dentoalveolar mechanical pain thresholds were determined with a custom-made device over the painful area for patients and were used as the stimulation level during functional magnetic resonance imaging (fMRI) data acquisition. Control subjects received two stimulation levels over matched locations during fMRI scanning: one determined (as above) that evoked equally subjective pain ratings matching those of patients (subjective-pain match) and another nonpainful stimulation level matching the average stimulus intensity provided to patients (stimulus-intensity match). Clinical and psychosocial data were analyzed using independent samples t tests, Mann-Whitney U test, and Spearman rank-order correlation coefficient. fMRI data were analyzed using validated neuroimaging software and tested using a general linear model. RESULTS PDAP patients had greater anxiety (P<.0001) and depression scores (P=.001), more jaw function impairment (P<.0001), and greater social impact (P<.0001) than controls. No significant differences were found for brain activation spatial extent (PDAP X Controls subjective pain: P=.48; PDAP X Controls stimulus intensity: P=.12). Brain activations were significantly increased for PDAP patients compared to control subjects when matched to stimulus intensity in several regions related to the sensory-discriminative and cognitive components of pain perception, including the primary and secondary somatosensory cortices, inferior parietal lobule, insula, premotor cortex, prefrontal cortex, and thalamus. When matched to subjective pain ratings, increased brain activations were still present for PDAP patients compared to controls, although to a lesser extent. CONCLUSION The present results suggest that dentoalveolar pressure is processed differently in the brain of PDAP patients, and the increased activation in several brain areas is consistent with amplified pain processing.
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