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Bucci R, Koutris M, Palla S, Sepúlveda Rebaudo GF, Lobbezoo F, Michelotti A. Occlusal tactile acuity in temporomandibular disorder pain patients: A case-control study. J Oral Rehabil 2020; 47:923-929. [PMID: 32433776 DOI: 10.1111/joor.12996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/18/2020] [Accepted: 05/11/2020] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To compare the smallest thickness that can be perceived between occluding teeth (occlusal tactile acuity, OTA) of temporomandibular disorder pain (TMD-P) patients with that of control (CTR) individuals. METHODS Twenty TMD-P patients (17 women and 3 men, mean age: 31.3 ± 10.4 years) diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol and 20 age- and gender-matched controls (17 women and 3 men, mean age: 31.4 ± 10.5 years) were enrolled. The OTA was tested with 10 different thicknesses: 9 aluminium foils (8 µm-72 µm with a constant increment of 8 µm) and 1 sham test (without foil), each thickness being tested 10 times in random order (100 tests in total). The participants were instructed to close their mouth once and to report whether they felt the foil between their molar teeth. A between-group comparison (TMD-P vs CTR) was performed for each testing thickness (analysis of variance for repeated measurements, with Bonferroni multiple correction) (P < .005). RESULTS Significantly increased OTA was observed in the TMD-P group for the thicknesses between 8 µm and 40 µm, while no significant differences were found for the sham test and for the larger thicknesses tested (from 48 µm to 72 µm). CONCLUSIONS TMD-pain subjects presented an increased OTA as compared to controls.
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Affiliation(s)
- Rosaria Bucci
- University of Naples Federico II, Naples, Italy.,University of Salerno, Salerno, Italy
| | - Michail Koutris
- Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
| | | | | | - Frank Lobbezoo
- Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
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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: 10] [Impact Index Per Article: 2.5] [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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Harfeldt K, Alexander L, Lam J, Månsson S, Westergren H, Svensson P, Sundgren PC, Alstergren P. Spectroscopic differences in posterior insula in patients with chronic temporomandibular pain. Scand J Pain 2019; 18:351-361. [PMID: 29794260 DOI: 10.1515/sjpain-2017-0159] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/06/2018] [Indexed: 11/15/2022]
Abstract
Background and aims Chronic pain including temporomandibular disorder (TMD) pain involves a complex interplay between peripheral and central sensitization, endogenous modulatory pathways, cortical processing and integration and numerous psychological, behavioral and social factors. The aim of this study was to compare spectroscopic patterns of N-Acetyl-aspartate (NAA), total creatine (tCr), choline (Cho), myo-inositol (MI), glutamate (Glu), and the combination of Glu and glutamine in the posterior insula in patients with chronic generalized or regional chronic TMD pain (gTMD and rTMD, respectively) compared to healthy individuals (HI) in relation to clinical findings of TMD pain. Methods Thirty-six female patients with chronic rTMD or gTMD with at least 3 months duration were included in the study. Ten healthy women were included as controls. All participants completed a questionnaire that comprised assessment of degrees of depression, anxiety, stress, catastrophizing, pain intensity, disability and locations. A clinical Diagnostic Criteria for Temporomandibular Disorders examination that comprised assessment of pain locations, headache, mouth opening capacity, pain on mandibular movement, pain on palpation and temporomandibular joint noises was performed. Pressure-pain threshold (PPT) over the masseter muscle and temporal summation to pressure stimuli were assessed with an algometer. Within a week all participants underwent non-contrast enhanced MRI on a 3T MR scanner assessing T1-w and T2-w fluid attenuation inversion recovery. A single-voxel 1H-MRS examination using point-resolved spectroscopy was performed. The metabolite concentrations of NAA, tCr, Cho, MI, Glu and Glx were analyzed with the LC model. Metabolite levels were calculated as absolute concentrations, normalized to the water signal. Metabolite concentrations were used for statistical analysis from the LC model if the Cramér-Rao bounds were less than 20%. In addition, the ratios NAA/tCr, Cho/tCr, Glu/tCr and MI/tCr were calculated. Results The results showed significantly higher tCr levels within the posterior insula in patients with rTMD or gTMD pain than in HI (p=0.029). Cho was negatively correlated to maximum mouth opening capacity with or without pain (rs=-0.42, n=28, p=0.031 and rs=-0.48, n=28, p=0.034, respectively) as well as pressure-pain threshold on the hand (rs=-0.41, n=28, p=0.031). Glu was positively correlated to temporal summation to painful mechanical stimuli (rs=0.42, n=26, p=0.034). Conclusions The present study found that increased concentrations of Cho and Glu in the posterior insular cortex is related to clinical characteristics of chronic TMD pain, including generalized pain. These findings provide new evidence about the critical involvement of the posterior insular cortex and the neurobiology underlying TMD pain in both regional and generalized manifestations. Implications The findings in this study have indirect implications for the diagnosis and management of TMD patients. That said, the findings provide new evidence about the critical involvement of the posterior insular cortex and the neurobiology underlying TMD pain in both regional and generalized manifestations. It is also a further step towards understanding and accepting chronic pain as a disorder in itself.
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Affiliation(s)
- Kristin Harfeldt
- Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Malmö, Sweden
| | - Louise Alexander
- Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Malmö, Sweden
| | - Julia Lam
- Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Malmö, Sweden
| | - Sven Månsson
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Hans Westergren
- Department of Pain Rehabilitation, Skåne University Hospital, Lund, Sweden.,Department of Health Sciences, Lund University, Lund, Sweden
| | - Peter Svensson
- Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark.,Orofacial Pain and Jaw Function, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - Pia C Sundgren
- Center for Imaging and function, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Institution for Clinical Sciences, Lund University, Lund, Sweden
| | - Per Alstergren
- Orofacial Pain and Jaw Function, Faculty of Odontology, Malmö University, Malmö, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Malmö, Sweden.,Department of Pain Rehabilitation, Skåne University Hospital, Lund, Sweden.,Department of Health Sciences, Lund University, Lund, Sweden.,Orofacial Pain Unit, Faculty of Odontology, Malmö University, Malmö, Sweden
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He S, Li F, Gu T, Ma H, Li X, Zou S, Huang X, Lui S, Gong Q, Chen S. Reduced corticostriatal functional connectivity in temporomandibular disorders. Hum Brain Mapp 2018; 39:2563-2572. [PMID: 29504182 PMCID: PMC6866295 DOI: 10.1002/hbm.24023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 12/22/2017] [Accepted: 02/19/2018] [Indexed: 02/05/2023] Open
Abstract
Although temporomandibular disorders (TMD) have been associated with abnormal gray matter volumes in cortical areas and in the striatum, the corticostriatal functional connectivity (FC) of patients with TMD has not been studied. Here, we studied 30 patients with TMD and 20 healthy controls that underwent clinical evaluations, including Helkimo indices, pain assessments, and resting-state functional magnetic resonance imaging scans. The FCs of the striatal regions with the other brain areas were examined with a seed-based approach. As seeds, we used the dorsal caudate, ventral caudate/nucleus accumbens, dorsal caudal putamen, and ventral rostral putamen regions. Voxel-wise comparisons with controls revealed that the patients with TMD exhibited reduced FCs in the ventral corticostriatal circuitry, between the ventral striatum and ventral frontal cortices, including the anterior cingulate cortex and anterior insula; in the dorsal corticostriatal circuitry, between the dorsal striatum and the dorsal cortices, including the precentral gyrus and supramarginal gyrus; and also within the striatum. Additionally, we explored correlations between the reduced corticostriatal FCs and clinical measurements. These results directly supported the hypothesis that TMD is associated with reduced FCs in brain corticostriatal networks and that these reduced FCs may underlie the deficits in motor control, pain processing, and cognition in TMD. Our findings may contribute to the understanding of the etiologies and pathologies of TMD.
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Affiliation(s)
- Shushu He
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
| | - Fei Li
- Huaxi MR Research Center (HMRRC), Department of RadiologyWest China Hospital of Sichuan UniversityChengduSichuanChina
| | - Tian Gu
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
| | - Huayu Ma
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
| | - Xinyi Li
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
| | - Shujuan Zou
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
| | - Xiaoqi Huang
- Huaxi MR Research Center (HMRRC), Department of RadiologyWest China Hospital of Sichuan UniversityChengduSichuanChina
| | - Su Lui
- Huaxi MR Research Center (HMRRC), Department of RadiologyWest China Hospital of Sichuan UniversityChengduSichuanChina
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of RadiologyWest China Hospital of Sichuan UniversityChengduSichuanChina
| | - Song Chen
- State Key Laboratory of Oral Disease, Department of OrthodonticsWest China School of Stomatology, Sichuan UniversityChengduSichuanChina
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Van Damme S, Vanden Bulcke C, Van Den Berghe L, Poppe L, Crombez G. Do patients with chronic unilateral orofacial pain due to a temporomandibular disorder show increased attending to somatosensory input at the painful side of the jaw? PeerJ 2018; 6:e4310. [PMID: 29379693 PMCID: PMC5786881 DOI: 10.7717/peerj.4310] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/10/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Patients with chronic orofacial pain due to temporomandibular disorders (TMD) display alterations in somatosensory processing at the jaw, such as amplified perception of tactile stimuli, but the underlying mechanisms remain unclear. This study investigated one possible explanation, namely hypervigilance, and tested if TMD patients with unilateral pain showed increased attending to somatosensory input at the painful side of the jaw. METHODS TMD patients with chronic unilateral orofacial pain (n = 20) and matched healthy volunteers (n = 20) performed a temporal order judgment (TOJ) task indicated which one of two tactile stimuli, presented on each side of the jaw, they had perceived first. TOJ methodology allows examining spatial bias in somatosensory processing speed. Furthermore, after each block of trials, the participants rated the perceived intensity of tactile stimuli separately for both sides of the jaw. Finally, questionnaires assessing pain catastrophizing, fear-avoidance beliefs, and pain vigilance, were completed. RESULTS TMD patients tended to perceive tactile stimuli at the painful jaw side as occurring earlier in time than stimuli at the non-painful side but this effect did not reach conventional levels of significance (p = .07). In the control group, tactile stimuli were perceived as occurring simultaneously. Secondary analyses indicated that the magnitude of spatial bias in the TMD group is positively associated with the extent of fear-avoidance beliefs. Overall, intensity ratings of tactile stimuli were significantly higher in the TMD group than in the control group, but there was no significant difference between the painful and non-painful jaw side in the TMD patients. DISCUSSION The hypothesis that TMD patients with chronic unilateral orofacial pain preferentially attend to somatosensory information at the painful side of the jaw was not statistically supported, although lack of power could not be ruled out as a reason for this. The findings are discussed within recent theories of pain-related attention.
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Affiliation(s)
- Stefaan Van Damme
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | | | | | - Louise Poppe
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Department of Movement and Sport Sciences, Ghent University, Ghent, Belgium
| | - Geert Crombez
- Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Center for Pain Research, University of Bath, Bath, United Kingdom
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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: 43] [Impact Index Per Article: 5.4] [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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James LM, Engdahl BE, Leuthold AC, Georgopoulos AP. Brain Correlates of Human Leukocyte Antigen (HLA) Protection in Gulf War Illness (GWI). EBioMedicine 2016; 13:72-79. [PMID: 27765642 PMCID: PMC5264269 DOI: 10.1016/j.ebiom.2016.10.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND We recently reported that six alleles from class II genes of the Human Leukocyte Antigen (HLA) confer protection from Gulf War Illness (GWI) (Georgopoulos et al., 2015). The most significant effect is exerted on Neurological-Cognitive-Mood (NCM), Pain, and Fatigue symptoms, such that higher number of copies of the protective alleles are associated with lower symptom severity. Here we tested the hypothesis that this effect is exerted by modulating the strength of neural synchronicity. METHODS Eighty-one Gulf War veterans (65 with GWI and 16 healthy controls) underwent a magnetoencephalography (MEG) scan to assess the strength of brain synchronicity by computing zero-lag crosscorrelations (and their Fisher z transforms) between prewhitened MEG time series. A high-resolution HLA genotyping determined the number of copies, k, of the 6 protective alleles above in each participant. We tested the hypothesis above by regressing NCM, Pain and Fatigue symptom severity against the interaction term, k×z (HLA-related effect), while including z (non-HLA-related effect), gender and age as covariates. The k×z and z terms assessed HLA- and non-HLA-related effects, respectively, of neural synchronicity on symptom severity. The distributions of these effects in sensor space were visualized using statistical heatmaps. FINDINGS We found significant, graded HLA- and non-HLA-related effects: (a) NCM>Pain>Fatigue for HLA-related effects, (b) NCM>Fatigue>Pain for non-HLA-related effects, and (c) HLA-related>non-HLA-related effects for all symptoms. These effects had widespread but distinct distributions in sensor space that allowed the orderly separation of the 6 terms (3 symptom domains×2 HLA factors) in a multidimensional plot, where one dimension separated the symptoms and the other the HLA relation. INTERPRETATION These findings demonstrate the presence of substantial, widespread, distinct and orderly HLA- and non-HLA-related neural influences on NCM, Pain and Fatigue symptom severity in GWI. FUNDING U.S. Department of Veterans Affairs and University of Minnesota.
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Affiliation(s)
- Lisa M James
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN 55455, USA; Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Brian E Engdahl
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN 55455, USA; Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Arthur C Leuthold
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Apostolos P Georgopoulos
- Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA; Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN 55455, USA; Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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8
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He SS, Li F, Gu T, Liu Y, Zou SJ, Huang XQ, Lui S, Gong QY, Chen S. Altered neural activation pattern during teeth clenching in temporomandibular disorders. Oral Dis 2016; 22:406-14. [PMID: 26913995 DOI: 10.1111/odi.12465] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 01/28/2016] [Accepted: 02/11/2016] [Indexed: 02/05/2023]
Affiliation(s)
- SS He
- Department of Orthodontics; State Key Laboratory of Oral Disease; West China School of Stomatology; Sichuan University; Chengdu Sichuan China
| | - F Li
- Department of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital of Sichuan University; Chengdu Sichuan China
| | - T Gu
- Department of Orthodontics; State Key Laboratory of Oral Disease; West China School of Stomatology; Sichuan University; Chengdu Sichuan China
| | - Y Liu
- Department of Orthodontics; State Key Laboratory of Oral Disease; West China School of Stomatology; Sichuan University; Chengdu Sichuan China
| | - SJ Zou
- Department of Orthodontics; State Key Laboratory of Oral Disease; West China School of Stomatology; Sichuan University; Chengdu Sichuan China
| | - XQ Huang
- Department of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital of Sichuan University; Chengdu Sichuan China
| | - S Lui
- Department of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital of Sichuan University; Chengdu Sichuan China
| | - QY Gong
- Department of Radiology; Huaxi MR Research Center (HMRRC); West China Hospital of Sichuan University; Chengdu Sichuan China
| | - S Chen
- Department of Orthodontics; State Key Laboratory of Oral Disease; West China School of Stomatology; Sichuan University; Chengdu Sichuan China
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Venkatesan L, Barlow SM, Popescu M, Popescu A. Integrated approach for studying adaptation mechanisms in the human somatosensory cortical network. Exp Brain Res 2014; 232:3545-54. [PMID: 25059913 DOI: 10.1007/s00221-014-4043-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 07/11/2014] [Indexed: 11/25/2022]
Abstract
Magnetoencephalography and independent component analysis (ICA) was utilized to study and characterize neural adaptation in the somatosensory cortical network. Repetitive punctate tactile stimuli were applied unilaterally to the dominant hand and face using a custom-built pneumatic stimulator called the TAC-Cell. ICA-based source estimation from the evoked neuromagnetic responses indicated cortical activity in the contralateral primary somatosensory cortex (SI) for face stimulation, while hand stimulation resulted in robust contralateral SI and posterior parietal cortex (PPC) activation. Activity was also observed in the secondary somatosensory cortical area (SII) with reduced amplitude and higher variability across subjects. There was a significant difference in adaptation rate between SI and higher-order somatosensory cortices for hand stimulation. Adaptation was significantly dependent on stimulus frequency and pulse index within the stimulus train for both hand and face stimulation. The peak latency of the activity was significantly dependent on stimulation site (hand vs. face) and cortical area (SI vs. PPC). The difference in the peak latency of activity in SI and PPC is presumed to reflect a hierarchical serial-processing mechanism in the somatosensory cortex.
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Affiliation(s)
- Lalit Venkatesan
- Communication Neuroscience Laboratories, University of Nebraska, 141 Barkley Memorial Center, Lincoln, NE, 68583, USA,
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KIM SE, CHANG L. Overlap between functional GI disorders and other functional syndromes: what are the underlying mechanisms? Neurogastroenterol Motil 2012; 24:895-913. [PMID: 22863120 PMCID: PMC3812246 DOI: 10.1111/j.1365-2982.2012.01993.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Irritable bowel syndrome and other gastrointestinal (GI) and non-GI disorders such as functional dyspepsia, fibromyalgia, temporomandibular joint disorder, interstitial cystitis/painful bladder syndrome, and chronic fatigue syndrome are known as functional pain syndromes. They commonly coexist within the same individual. The pathophysiologic mechanisms of these disorders are not well understood, but it has been hypothesized that they share a common pathogenesis. PURPOSE The objective of this review is to discuss the proposed pathophysiologic mechanisms, which have been similarly studied in these conditions. These mechanisms include enhanced pain perception, altered regional brain activation, infectious etiologies, dysregulations in immune and neuroendocrine function, and genetic susceptibility. Studies suggest that these functional disorders are multifactorial, but factors which increase the vulnerability of developing these conditions are shared.
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Affiliation(s)
- S. E. KIM
- Oppenheimer Family Center of Neurobiology of Stress, Los Angeles, CA, USA
,Department of Medicine, Greater Los Angeles Veterans Administration Medical Center, Los Angeles, CA, USA
| | - L. CHANG
- Oppenheimer Family Center of Neurobiology of Stress, Los Angeles, CA, USA
,Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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