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Ma L, Yue L, Liu S, Xu S, Tong J, Sun X, Su L, Cui S, Liu FY, Wan Y, Yi M. A distinct neuronal ensemble of prelimbic cortex mediates spontaneous pain in rats with peripheral inflammation. Nat Commun 2024; 15:7922. [PMID: 39256428 PMCID: PMC11387830 DOI: 10.1038/s41467-024-52243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 08/30/2024] [Indexed: 09/12/2024] Open
Abstract
The absence of a comprehensive understanding of the neural basis of spontaneous pain limits the development of therapeutic strategies targeting this primary complaint of patients with chronic pain. Here we report a distinct neuronal ensemble within the prelimbic cortex which processes signals related to spontaneous pain in rats with chronic inflammatory pain. This neuronal ensemble specifically encodes spontaneous pain-related behaviors, independently of other locomotive and evoked behaviors. Activation of this neuronal ensemble elicits marked spontaneous pain-like behaviors and enhances nociceptive responses, whereas prolonged silencing of its activities alleviates spontaneous pain and promotes overall recovery from inflammatory pain. Notably, afferents from the primary somatosensory cortex and infralimbic cortex bidirectionally modulate the activities of the spontaneous pain-responsive prelimbic cortex neuronal ensemble and pain behaviors. These findings reveal the cortical basis of spontaneous pain at the neuronal level, highlighting a distinct neuronal ensemble within the prelimbic cortex and its associated pain-regulatory brain networks.
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Affiliation(s)
- Longyu Ma
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Lupeng Yue
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Science, Beijing, China
| | - Shuting Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Shi Xu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Jifu Tong
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Xiaoyan Sun
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Li Su
- Center of Medical and Health Analysis, Peking University, Beijing, China
| | - Shuang Cui
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Feng-Yu Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education / National Health Commission, Peking University, Beijing, China.
- Beijing Life Science Academy, Beijing, China.
| | - Ming Yi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education / National Health Commission, Peking University, Beijing, China.
- Medical Innovation Center (Taizhou) of Peking University, Taizhou, China.
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2
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Rueff EM. Visual discomfort and contact lens wear: A review. Cont Lens Anterior Eye 2023; 46:101872. [PMID: 37277259 DOI: 10.1016/j.clae.2023.101872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/22/2023] [Accepted: 05/30/2023] [Indexed: 06/07/2023]
Abstract
The purpose of this manuscript is to describe how vision influences contact lens discomfort and review the evidence supporting the hypothesis that contact lens discomfort can be caused by vision and vision-related disorders. Contact lens discomfort is a misunderstood and difficult to manage clinical condition. Most treatments and strategies aimed at alleviating discomfort focus on optimizing the contact lens fit and its relationship with the ocular surface, but these strategies commonly fail at relieving discomfort symptoms. Many vision and vision-related disorders share symptoms with those reported by uncomfortable contact lens wearers. This paper will review evidence and literature that describes how these vision and vision-related disorders may influence comfort in contact lens wearers. Acknowledging how vision influences contact lens discomfort will improve future research intended to better understand the condition, allow for more effective clinical management, and reduce rates of discontinuation.
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Affiliation(s)
- Erin M Rueff
- The Southern California College of Optometry at Marshall B Ketchum University, 2575 Yorba Linda Blvd, Fullerton, CA 92831, USA.
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3
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Ma L, Liu S, Yi M, Wan Y. Spontaneous pain as a challenge of research and management in chronic pain. MEDICAL REVIEW (BERLIN, GERMANY) 2022; 2:308-319. [PMID: 37724190 PMCID: PMC10388751 DOI: 10.1515/mr-2022-0007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/31/2022] [Indexed: 09/20/2023]
Abstract
Spontaneous pain occurring without apparent external stimuli, is a significant complaint of individuals with chronic pain whose mechanisms, somewhat surprisingly, remain poorly understood. Over the past decades, neuroimaging studies start to reveal brain activities accompanying spontaneous pain. Meanwhile, a variety of animal models and behavioral tests have been established, including non-reflexive tests and free-choice tests, which have been shown to be effective in assessing spontaneous pain. For the spontaneous pain mechanisms, multiple lines of research mainly focus on three aspects: (1) sensitization of peripheral nociceptor receptors and ion channels, (2) spontaneous neuronal firing and abnormal activity patterns at the dorsal root ganglion and spinal cord level, (3) functional and structural alterations in the brain, particularly the limbic system and the medial pain pathway. Despite accumulating evidence revealing distinct neuronal mechanisms from evoked pain, we are still far from full understanding of spontaneous pain, leaving a big gap between bench and bedside for chronic pain treatment. A better understanding of the neural processes in chronic pain, with specific linkage as to which anatomical structures and molecules related to spontaneous pain perception and comorbidities, will greatly improve our ability to develop novel therapeutics.
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Affiliation(s)
- Longyu Ma
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Shuting Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Ming Yi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
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4
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Black SR, King JB, Mahan MA, Anderson J, Butson CR. Functional Hyperconnectivity and Task-Based Activity Changes Associated With Neuropathic Pain After Spinal Cord Injury: A Pilot Study. Front Neurol 2021; 12:613630. [PMID: 34177753 PMCID: PMC8222514 DOI: 10.3389/fneur.2021.613630] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 05/07/2021] [Indexed: 01/05/2023] Open
Abstract
Neuropathic pain (NP) is a devastating chronic pain condition affecting roughly 80% of the spinal cord injury (SCI) patient population. Current treatment options are largely ineffective and neurophysiological mechanisms of NP are not well-understood. Recent studies in neuroimaging have suggested that NP patients have differential patterns of functional activity that are dependent upon the neurological condition causing NP. We conducted an exploratory pilot study to examine functional activation and connectivity in SCI patients with chronic NP compared to SCI patients without NP. We developed a novel somatosensory attention task to identify short term fluctuations in neural activity related to NP vs. non-painful somatosensation using functional magnetic resonance imaging (fMRI). We also collected high-resolution resting state fMRI to identify connectivity-based correlations over time between the two groups. We observed increased activation during focus on NP in brain regions associated with somatosensory integration and representational knowledge in pain subjects when compared with controls. Similarly, NP subjects showed increased connectivity at rest in many of the same areas of the brain, with positive correlations between somatomotor networks, the dorsal attention network, and regions associated with pain and specific areas of painful and non-painful sensation within our cohort. Although this pilot analysis did not identify statistically significant differences between groups after correction for multiple comparisons, the observed correlations between NP and functional activation and connectivity align with a priori hypotheses regarding pain, and provide a well-controlled preliminary basis for future research in this severely understudied patient population. Altogether, this study presents a novel task, identifies regions of increased task-based activation associated with NP after SCI in the insula, prefrontal, and medial inferior parietal cortices, and identifies similar regions of increased functional connectivity associated with NP after SCI in sensorimotor, cingulate, prefrontal, and inferior medial parietal cortices. This, along with our complementary results from a structurally based analysis, provide multi-modal evidence for regions of the brain specific to the SCI cohort as novel areas for further study and potential therapeutic targeting to improve outcomes for NP patients.
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Affiliation(s)
- Shana R Black
- Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States
| | - Jace B King
- Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States
| | - Mark A Mahan
- Neurosurgery, University of Utah, Salt Lake City, UT, United States
| | - Jeffrey Anderson
- Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, United States
| | - Christopher R Butson
- Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States.,Neurosurgery, University of Utah, Salt Lake City, UT, United States.,Neurology, University of Utah, Salt Lake City, UT, United States.,Psychiatry, University of Utah, Salt Lake City, UT, United States
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5
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Xiao Z, Martinez E, Kulkarni PM, Zhang Q, Hou Q, Rosenberg D, Talay R, Shalot L, Zhou H, Wang J, Chen ZS. Cortical Pain Processing in the Rat Anterior Cingulate Cortex and Primary Somatosensory Cortex. Front Cell Neurosci 2019; 13:165. [PMID: 31105532 PMCID: PMC6492531 DOI: 10.3389/fncel.2019.00165] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 04/08/2019] [Indexed: 01/08/2023] Open
Abstract
Pain is a complex multidimensional experience encompassing sensory-discriminative, affective-motivational and cognitive-emotional components mediated by different neural mechanisms. Investigations of neurophysiological signals from simultaneous recordings of two or more cortical circuits may reveal important circuit mechanisms on cortical pain processing. The anterior cingulate cortex (ACC) and primary somatosensory cortex (S1) represent two most important cortical circuits related to sensory and affective processing of pain. Here, we recorded in vivo extracellular activity of the ACC and S1 simultaneously from male adult Sprague-Dale rats (n = 5), while repetitive noxious laser stimulations were delivered to animalÕs hindpaw during pain experiments. We identified spontaneous pain-like events based on stereotyped pain behaviors in rats. We further conducted systematic analyses of spike and local field potential (LFP) recordings from both ACC and S1 during evoked and spontaneous pain episodes. From LFP recordings, we found stronger phase-amplitude coupling (theta phase vs. gamma amplitude) in the S1 than the ACC (n = 10 sessions), in both evoked (p = 0.058) and spontaneous pain-like behaviors (p = 0.017, paired signed rank test). In addition, pain-modulated ACC and S1 neuronal firing correlated with the amplitude of stimulus-induced event-related potentials (ERPs) during evoked pain episodes. We further designed statistical and machine learning methods to detect pain signals by integrating ACC and S1 ensemble spikes and LFPs. Together, these results reveal differential coding roles between the ACC and S1 in cortical pain processing, as well as point to distinct neural mechanisms between evoked and putative spontaneous pain at both LFP and cellular levels.
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Affiliation(s)
- Zhengdong Xiao
- Department of Instrument Science and Technology, Zhejiang University, Hangzhou, China.,Department of Psychiatry, New York University School of Medicine, New York, NY, United States
| | - Erik Martinez
- Department of Psychiatry, New York University School of Medicine, New York, NY, United States.,Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States
| | - Prathamesh M Kulkarni
- Department of Psychiatry, New York University School of Medicine, New York, NY, United States
| | - Qiaosheng Zhang
- Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States
| | - Qianning Hou
- Department of Psychiatry, New York University School of Medicine, New York, NY, United States.,Department of Biophysics, University of Science and Technology of China, Hefei, China
| | - David Rosenberg
- New York University School of Medicine, New York, NY, United States
| | - Robert Talay
- Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States
| | - Leor Shalot
- Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States
| | - Haocheng Zhou
- Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States
| | - Jing Wang
- Department of Anesthesiology, Perioperative Care and Pain Medicine, New York University School of Medicine, New York, NY, United States.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, United States
| | - Zhe Sage Chen
- Department of Psychiatry, New York University School of Medicine, New York, NY, United States.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, United States.,Neuroscience Institute, New York University School of Medicine, New York, NY, United States
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6
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Abstract
OBJECTIVES Many patients with painful chronic pancreatitis (CP) have insufficient effect of treatment, and the prevalence of adverse effects is high. Consequently, alternatives to conventional management are needed. We aimed to study the effect of acupuncture in painful CP. METHODS This was a prospective, single-blinded, randomized crossover trial. Fifteen patients with CP were assigned to a session of acupuncture followed by sham stimulation or vice versa. Patients rated clinical pain scores daily on a 0 to 10 visual analogue scale (VAS) and completed the Patient Global Impression of Change. For mechanistic linkage, resting state electroencephalograms were recorded and quantified by spectral power analysis to explore effects on central pain processing. RESULTS Acupuncture, compared with sham stimulation, caused more pain relief (2.0 ± 1.5 VAS vs 0.7 ± 0.8 VAS; P = 0.009). The effect, however, was short, and after 1-week follow-up, there was no difference in clinical pain scores between groups (P = 1.0) or the rating of Patient Global Impression of Change (P = 0.8). Electroencephalogram spectral power distributions between sham and acupuncture were comparable between groups (all P > 0.6). CONCLUSIONS The study presents proof-of-concept for the analgesic effect of acupuncture in pancreatic pain. Although the effect was short lasting, the framework may be used to conceptualize future trials of acupuncture in visceral pain.
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7
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Alomar S, Bakhaidar M. Neuroimaging of neuropathic pain: review of current status and future directions. Neurosurg Rev 2016; 41:771-777. [DOI: 10.1007/s10143-016-0807-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/24/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
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8
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Tanasescu R, Cottam WJ, Condon L, Tench CR, Auer DP. Functional reorganisation in chronic pain and neural correlates of pain sensitisation: A coordinate based meta-analysis of 266 cutaneous pain fMRI studies. Neurosci Biobehav Rev 2016; 68:120-133. [PMID: 27168346 PMCID: PMC5554296 DOI: 10.1016/j.neubiorev.2016.04.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 12/19/2022]
Abstract
Maladaptive mechanisms of pain processing in chronic pain conditions (CP) are poorly understood. We used coordinate based meta-analysis of 266 fMRI pain studies to study functional brain reorganisation in CP and experimental models of hyperalgesia. The pattern of nociceptive brain activation was similar in CP, hyperalgesia and normalgesia in controls. However, elevated likelihood of activation was detected in the left putamen, left frontal gyrus and right insula in CP comparing stimuli of the most painful vs. other site. Meta-analysis of contrast maps showed no difference between CP, controls, mood conditions. In contrast, experimental hyperalgesia induced stronger activation in the bilateral insula, left cingulate and right frontal gyrus. Activation likelihood maps support a shared neural pain signature of cutaneous nociception in CP and controls. We also present a double dissociation between neural correlates of transient and persistent pain sensitisation with general increased activation intensity but unchanged pattern in experimental hyperalgesia and, by contrast, focally increased activation likelihood, but unchanged intensity, in CP when stimulated at the most painful body part.
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Affiliation(s)
- Radu Tanasescu
- Clinical Neurology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK; Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK
| | - William J Cottam
- Radiological Sciences, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK; Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK
| | - Laura Condon
- Radiological Sciences, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK; Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK
| | - Christopher R Tench
- Clinical Neurology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Dorothee P Auer
- Radiological Sciences, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK; Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK.
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9
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Juel J, Liguori S, Liguori A, Valeriani M, Graversen C, Olesen SS, Drewes AM. A New Method for Sham-Controlled Acupuncture in Experimental Visceral Pain - a Randomized, Single-Blinded Study. Pain Pract 2015; 16:669-79. [DOI: 10.1111/papr.12309] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 03/02/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Jacob Juel
- Mech-Sense; Department of Gastroenterology and Hepatology; Aalborg University Hospital; Aalborg Denmark
| | | | - Aldo Liguori
- Istituto Paracelso; Rome Italy
- Department of Anatomic, Histologic; Forensic Medicine and Locomotor System Sciences; Faculty of Pharmacy and Medicine; Sapienza University; Rome Italy
| | - Massimiliano Valeriani
- Department of Neurology; Paediatric Hospital Bambino Gesù; Rome Italy
- Center for Sensory-Motor Interaction; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg Denmark
| | - Carina Graversen
- Mech-Sense; Department of Gastroenterology and Hepatology; Aalborg University Hospital; Aalborg Denmark
| | - Søren S. Olesen
- Mech-Sense; Department of Gastroenterology and Hepatology; Aalborg University Hospital; Aalborg Denmark
| | - Asbjørn M. Drewes
- Mech-Sense; Department of Gastroenterology and Hepatology; Aalborg University Hospital; Aalborg Denmark
- Center for Sensory-Motor Interaction; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg Denmark
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10
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Papuga MO, Burke JR, Dougherty PE. The reliability of a novel magnetic resonance compatible electro-pneumatic device for delivering a painful pressure stimulus over the lumbar spine. Somatosens Mot Res 2014; 32:51-60. [DOI: 10.3109/08990220.2014.960559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Central pain processing in chronic chemotherapy-induced peripheral neuropathy: a functional magnetic resonance imaging study. PLoS One 2014; 9:e96474. [PMID: 24821182 PMCID: PMC4018287 DOI: 10.1371/journal.pone.0096474] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/08/2014] [Indexed: 12/01/2022] Open
Abstract
Life expectancy in multiple myeloma has significantly increased. However, a high incidence of chemotherapy induced peripheral neuropathy (CIPN) can negatively influence quality of life during this period. This study applied functional magnetic resonance imaging (fMRI) to compare areas associated with central pain processing in patients with multiple myeloma who had chemotherapy induced peripheral neuropathy (MM-CIPN) with those from healthy volunteers (HV). Twenty-four participants (n = 12 MM-CIPN, n = 12 HV) underwent Blood Oxygen Level-Dependent (BOLD) fMRI at 3T whilst noxious heat-pain stimuli were applied to the foot and then thigh. Patients with MM-CIPN demonstrated greater activation during painful stimulation in the precuneus compared to HV (p = 0.014, FWE-corrected). Patients with MM-CIPN exhibited hypo-activation of the right superior frontal gyrus compared to HV (p = 0.031, FWE-corrected). Significant positive correlation existed between the total neuropathy score (reduced version) and activation in the frontal operculum (close to insular cortex) during foot stimulation in patients with MM-CIPN (p = 0.03, FWE-corrected; adjusted R2 = 0.87). Painful stimuli delivered to MM-CIPN patients evoke differential activation of distinct cortical regions, reflecting a unique pattern of central pain processing compared with healthy volunteers. This characteristic activation pattern associated with pain furthers the understanding of the pathophysiology of painful chemotherapy induced peripheral neuropathy. Functional MRI provides a tool for monitoring cerebral changes during anti-cancer and analgesic treatment.
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12
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Erpelding N, Borsook D. Capturing brain metrics of neuropathic pain using nuclear magnetic resonance. Pain Manag 2013; 3:395-409. [PMID: 24654873 DOI: 10.2217/pmt.13.42] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
SUMMARY Neuropathic pain is typically caused by a lesion or dysfunction in the nervous system that results in both negative (i.e., reduced sensitivity) and positive symptoms (i.e., paraesthesia, spontaneous ongoing pain with shooting, electric shock-like sensations and abnormal responses to evoked pain). Intriguingly, chronic pain disorders manifest profound alterations in brain structure and function, and thus, modern nuclear magnetic resonance (NMR) techniques have allowed us to begin to dissect the complexities of how neuropathic pain affects the brain. NMR approaches can be used as an independent measure to improve our understanding of key changes in brain structure, function and chemistry in chronic neuropathic pain. Accordingly, NMR techniques provide neurobiological metrics that allow us to understand the neurobiological basis of chronic neuropathic pain. Additionally, although at an early stage, NMR methods can also be useful to define clinical metrics to predict chronification of neuropathic pain and responses to drugs. This article provides a review of NMR techniques and their capacity to study spontaneous pain and evoked pain, as well as structural, functional and neurochemical alterations that have repeatedly been associated with chronic neuropathic pain. Finally, the importance for quantifying disease state and treatment efficacy in neuropathic pain using NMR techniques is discussed.
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Affiliation(s)
- Nathalie Erpelding
- P.A.I.N. Group, Boston Children's Hospital, 9 Hope Avenue, Waltham, MA 02453, USA
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13
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Höke A, Simpson DM, Freeman R. Challenges in developing novel therapies for peripheral neuropathies: a summary of The Foundation for Peripheral Neuropathy Scientific Symposium 2012. J Peripher Nerv Syst 2013; 18:1-6. [PMID: 23521637 DOI: 10.1111/jns5.12000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Roy Freeman
- Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center; Boston MA USA
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14
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Kornelsen J, Sboto-Frankenstein U, McIver T, Gervai P, Wacnik P, Berrington N, Tomanek B. Default mode network functional connectivity altered in failed back surgery syndrome. THE JOURNAL OF PAIN 2013; 14:483-91. [PMID: 23498869 DOI: 10.1016/j.jpain.2012.12.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 12/13/2012] [Accepted: 12/27/2012] [Indexed: 10/27/2022]
Abstract
UNLABELLED The purpose of this study was to identify alterations in the default mode network of failed back surgery syndrome patients as compared to healthy subjects. Resting state functional magnetic resonance imaging was conducted at 3 Tesla and data were analyzed with an independent component analysis. Results indicate an overall reduced functional connectivity of the default mode network and recruitment of additional pain modulation brain regions, including dorsolateral prefrontal cortex, insula, and additional sensory motor integration brain regions, including precentral and postcentral gyri, for failed back surgery syndrome patients. PERSPECTIVE This article presents alterations in the default mode network of chronic low back pain patients with failed back surgery syndrome as compared to healthy participants.
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Affiliation(s)
- Jennifer Kornelsen
- Magnetic Resonance Technology, Institute for Biodiagnostics, National Research Council Canada, Winnipeg, Canada.
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15
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Park JY, Ahn RS. Hypothalamic-pituitary-adrenal axis function in patients with complex regional pain syndrome type 1. Psychoneuroendocrinology 2012; 37:1557-68. [PMID: 22445364 DOI: 10.1016/j.psyneuen.2012.02.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 01/24/2012] [Accepted: 02/28/2012] [Indexed: 01/09/2023]
Abstract
An exaggerated inflammatory process is considered an important pathophysiological feature of complex regional pain syndrome type 1 (CRPS-1). The hypothalamic-pituitary-adrenal (HPA) axis serves as a negative feedback mechanism for inflammatory processes. The present study examined the HPA axis function in patients with CRPS-1 by a determination of cortisol concentrations in saliva. Three sets of saliva samples were sequentially collected from 24 patients with CRPS-1 during medication (on-Med), 72 h after stopping medication (off-Med) and 8h after the oral administration of 1mg dexamethasone. One set of saliva samples was collected from healthy controls. The cortisol awakening response (CAR) and diurnal cortisol decline (DCD) were used as indices for HPA axis function. Cortisol levels during the post-awakening period in patients were increased following withdrawal of medications. The CAR during the off-Med condition was disappeared after administration of dexamethasone. Among the examined CRPS-related numerical variables, the frequency of spontaneous pain attacks showed relationships with the indices of HPA axis function. After classifying the patients into two subgroups, we observed that the CAR and DCD in patient who had a relatively high frequency of spontaneous pain attacks (subgroup 5 ≤) were lower and less steep than those in patient who had a relatively low frequency of spontaneous pain attacks (subgroup 0-4) for the on- and off-Med conditions. The CAR and DCD in subgroup 5 ≤ during their off-Med condition were comparable to those in controls. These results suggest that the increase in frequency of spontaneous pain attacks is associated with a reduced CAR and flattened DCD in patients CRPS-1.
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Affiliation(s)
- Jai Y Park
- Department of Anesthesiology and Pain Medicine, The Armed Forces Capital Hospital, Seoul, Republic of Korea
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16
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Graversen C, Olesen SS, Olesen AE, Steimle K, Farina D, Wilder-Smith OHG, Bouwense SAW, van Goor H, Drewes AM. The analgesic effect of pregabalin in patients with chronic pain is reflected by changes in pharmaco-EEG spectral indices. Br J Clin Pharmacol 2012; 73:363-72. [PMID: 21950372 DOI: 10.1111/j.1365-2125.2011.04104.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIM To identify electroencephalographic (EEG) biomarkers for the analgesic effect of pregabalin in patients with chronic visceral pain. METHODS This was a double-blind, placebo-controlled study in 31 patients suffering from visceral pain due to chronic pancreatitis. Patients received increasing doses of pregabalin (75mg-300mg twice a day) or matching placebo during 3 weeks of treatment. Pain scores were documented in a diary based on a visual analogue scale. In addition, brief pain inventory-short form (BPI) and quality of life questionnaires were collected prior to and after the study period. Multi-channel resting EEG was recorded before treatment onset and at the end of the study. Changes in EEG spectral indices were extracted, and individual changes were classified by a support vector machine (SVM) to discriminate the pregabalin and placebo responses. Changes in individual spectral indices and pain scores were correlated. RESULTS Pregabalin increased normalized intensity in low spectral indices, most prominent in the theta band (3.5-7.5Hz), difference of -3.18, 95% CI -3.57, -2.80; P= 0.03. No changes in spectral indices were seen for placebo. The maximum difference between pregabalin and placebo treated patients was seen in the parietal region, with a classification accuracy of 85.7% (P= 0.009). Individual changes in EEG indices were correlated with changes in pain diary (P= 0.04) and BPI pain composite scores (P= 0.02). CONCLUSIONS Changes in spectral indices caused by slowing of brain oscillations were identified as a biomarker for the central analgesic effect of pregabalin. The developed methodology may provide perspectives to assess individual responses to treatment in personalized medicine.
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Affiliation(s)
- Carina Graversen
- Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Aarhus University Hospital, Aalborg, Denmark
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Tseng MT, Chiang MC, Chao CC, Tseng WYI, Hsieh ST. fMRI evidence of degeneration-induced neuropathic pain in diabetes: enhanced limbic and striatal activations. Hum Brain Mapp 2012; 34:2733-46. [PMID: 22522975 DOI: 10.1002/hbm.22105] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 01/30/2012] [Accepted: 03/19/2012] [Indexed: 12/13/2022] Open
Abstract
Persistent neuropathic pain due to peripheral nerve degeneration in diabetes is a stressful symptom; however, the underlying neural substrates remain elusive. This study attempted to explore neuroanatomical substrates of thermal hyperalgesia and burning pain in a diabetic cohort due to pathologically proven cutaneous nerve degeneration (the painful group). By applying noxious 44°C heat stimuli to the right foot to provoke neuropathic pain symptoms, brain activation patterns were compared with those of healthy control subjects and patients with a similar degree of cutaneous nerve degeneration but without pain (the painless group). Psychophysical results showed enhanced affective pain ratings in the painful group. After eliminating the influence of different pain intensity ratings on cerebral responses, the painful group displayed augmented responses in the limbic and striatal structures, including the perigenual anterior cingulate cortex (ACC), superior frontal gyrus, medial thalamus, anterior insular cortex, lentiform nucleus (LN), and premotor area. Among these regions, blood oxygen level-dependent (BOLD) signals in the ACC and LN were correlated with pain ratings to thermal stimulations in the painful group. Furthermore, activation maps of a simple regression analysis as well as a region of interest analysis revealed that responses in these limbic and striatal circuits paralleled the duration of neuropathic pain. However, in the painless group, BOLD signals in the primary somatosensory cortex and ACC were reduced. These results suggest that enhanced limbic and striatal activations underlie maladaptive responses after cutaneous nerve degeneration, which contributed to the development and maintenance of burning pain and thermal hyperalgesia in diabetes.
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Affiliation(s)
- Ming-Tsung Tseng
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan; Section of Neurology, Department of Internal Medicine, Far Eastern Memorial Hospital, Taipei, Taiwan
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Borsook D, Becerra L. How close are we in utilizing functional neuroimaging in routine clinical diagnosis of neuropathic pain? Curr Pain Headache Rep 2012; 15:223-9. [PMID: 21369853 DOI: 10.1007/s11916-011-0187-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
As with many disorders affecting the central nervous system, treatment of chronic pain is fraught with difficulties related to specific diagnosis and measures of treatment efficacy. Given the recent advances that brain-imaging techniques have contributed to our understanding of how chronic pain affects multiple aspects of brain function (including sensory, emotional, cognitive, and modulatory), opportunities to use these approaches in the clinic are clearly a focus of research laboratories around the world. The routine application of brain imaging as a clinical marker of disease state or therapeutic (drug) efficacy would significantly enhance the clinical process by providing objective measures for clinicians and patients.
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Affiliation(s)
- David Borsook
- Center for Pain and the Brain, c/o Brain Imaging Center, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
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19
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The corneal pain system. Part I: the missing piece of the dry eye puzzle. Ocul Surf 2012; 10:2-14. [PMID: 22330055 DOI: 10.1016/j.jtos.2012.01.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 12/09/2011] [Accepted: 12/12/2011] [Indexed: 01/23/2023]
Abstract
The traditional model of dry eye disease based on tear deficiency has presented us with many unanswered questions. Recent studies support the notion that dry eye-like symptoms represent non-specific corneal pain and provide new insights into the mechanisms that sustain the integrity of the optical tear layer. Thus, this enigmatic disease can be viewed with a new perspective, which involves the dysfunctional corneal pain system as a central pathogenetic feature of a series of disorders collectively known today as dry eye.
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Masri R, Keller A. Chronic pain following spinal cord injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 760:74-88. [PMID: 23281514 PMCID: PMC3560294 DOI: 10.1007/978-1-4614-4090-1_5] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Most patients with insults to the spinal cord or central nervous system suffer from excruciating, unrelenting, chronic pain that is largely resistant to treatment. This condition affects a large percentage of spinal cord injury patients, and numerous patients with multiple sclerosis, stroke and other conditions. Despite the recent advances in basic science and clinical research the pathophysiological mechanisms of pain following spinal cord injury remain unknown. Here we describe a novel mechanism of loss of inhibition within the thalamus that may predispose for the development of this chronic pain and discuss a potential treatment that may restore inhibition and ameliorate pain.
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Affiliation(s)
- Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, Baltimore College of Dental Surgery, University of Maryland Baltimore, Baltimore, Maryland, USA.
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21
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22
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Hainline B. Neuropathic Pain. Pain Manag 2011. [DOI: 10.1016/b978-1-4377-0721-2.00023-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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23
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Abstract
Emerging research in neuroscience is bridging the gap between mind and body. Thought is brain based and influences brain function. The continuum and bidirectionality of mind and body, thought and brain, emotions and physiology forms the basis of understanding neuropathic pain, a neuropsychiatric condition with myriad clinical manifestations.
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Schwenkreis P, Scherens A, Rönnau AK, Höffken O, Tegenthoff M, Maier C. Cortical disinhibition occurs in chronic neuropathic, but not in chronic nociceptive pain. BMC Neurosci 2010; 11:73. [PMID: 20540759 PMCID: PMC2898830 DOI: 10.1186/1471-2202-11-73] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 06/11/2010] [Indexed: 11/10/2022] Open
Abstract
Background The aim of this study was to examine the relationship between chronic neuropathic pain after incomplete peripheral nerve lesion, chronic nociceptive pain due to osteoarthritis, and the excitability of the motor cortex assessed by transcranial magnetic stimulation (TMS). Hence in 26 patients with neuropathic pain resulting from an isolated incomplete lesion of the median or ulnar nerve (neuralgia), 20 patients with painful osteoarthritis of the hand, and 14 healthy control subjects, the excitability of the motor cortex was tested using paired-pulse TMS to assess intracortical inhibition and facilitation. These excitability parameters were compared between groups, and the relationship between excitability parameters and clinical parameters was examined. Results We found a significant reduction of intracortical inhibition in the hemisphere contralateral to the lesioned nerve in the neuralgia patients. Intracortical inhibition in the ipsilateral hemisphere of neuralgia patients and in both hemispheres of osteoarthritis patients did not significantly differ from the control group. Disinhibition was significantly more pronounced in neuralgia patients with moderate/severe pain intensity than in patients with mild pain intensity, whereas the relative compound motor action potential as a parameter of nerve injury severity did not correlate with the amount of disinhibition. Conclusions Our results suggest a close relationship between motor cortex inhibition and chronic neuropathic pain in the neuralgia patients, which is independent from nerve injury severity. The lack of cortical disinhibition in patients with painful osteoarthritis points at differences in the pathophysiological processes of different chronic pain conditions with respect to the involvement of different brain circuitry.
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Affiliation(s)
- Peter Schwenkreis
- Department of Neurology, Ruhr-University Bochum, BG-Universitätsklinikum Bergmannsheil, Bochum, Germany.
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Abstract
Pain is a complex subjective phenomenon that so far cannot be objectively quantified by any standardized procedure. This fact renders it also difficult to measure the efficacy of analgesic drugs. In recent years the application of functional magnetic resonance imaging (fMRI) has significantly increased our current knowledge about the brain physiological correlates of pain in humans. The technique is non-invasive and detects the increased blood flow into neuronally active brain regions based on the so-called BOLD (blood oxygenation level dependent) effect of T2-weighted MRI. This paper gives an overview of the application of pharmacological fMRI (phfMRI) as an approach to evaluate the efficacy of analgesics. In contrast to EEG- and MEG-based methods phfMRI allows more flexibility in the design of experimental paradigms and stimulus protocols to account for the diversity of clinical pain types (inflammatory pain, tactile allodynia etc.) or their dependence upon psychological circumstances (anxiety, depression, stress) in which pain occurs. However, in order to specifically refer results from phfMRI to the neuronal processes underlying pain, future research needs to increase the understanding of the mechanisms underlying the neurovascular coupling reaction represented by the BOLD technique. The same applies for the influence of cerebrovascular diseases on the BOLD response.
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26
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Ritter C, Bingel U. Neuroimaging the genomics of pain processing--a perspective. Neuroscience 2009; 164:141-55. [PMID: 19467296 DOI: 10.1016/j.neuroscience.2009.05.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/11/2009] [Accepted: 05/18/2009] [Indexed: 11/19/2022]
Abstract
The significant inter-individual variability in pain behavior and its contributing factors remains a pervasive clinical challenge and has generated intense scientific investigations in this field. Recent studies indicate that our genes considerably influence nociceptive information processes, how our nociceptive system copes with peripheral injury, and the individual response to analgesic treatments. Neuroimaging studies of pain are beginning to link such genetic influences with physiological processes in the human brain. This review presents the pioneering endeavors of the hybrid approach of neuroimaging pain genes in humans and identifies potential future directions.
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Affiliation(s)
- C Ritter
- Department of Neurology, Christian-Albrechts-University Kiel, Germany
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Masri R, Quiton RL, Lucas JM, Murray PD, Thompson SM, Keller A. Zona incerta: a role in central pain. J Neurophysiol 2009; 102:181-91. [PMID: 19403748 DOI: 10.1152/jn.00152.2009] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Central pain syndrome (CPS) is a debilitating condition that affects a large number of patients with a primary lesion or dysfunction in the CNS. Despite its discovery over a century ago, the pathophysiological processes underlying the development and maintenance of CPS are poorly understood. We recently demonstrated that activity in the posterior thalamus (PO) is tightly regulated by inhibitory inputs from zona incerta (ZI). Here we test the hypothesis that CPS is associated with abnormal inhibitory regulation of PO by ZI. We recorded single units from ZI and PO in animals with CPS resulting from spinal cord lesions. Consistent with our hypothesis, the spontaneous firing rate and somatosensory evoked responses of ZI neurons were lower in lesioned animals compared with sham-operated controls. In PO, neurons recorded from lesioned rats exhibited significantly higher spontaneous firing rates and greater responses to noxious and innocuous stimuli applied to the hindpaw and to the face. These changes were not associated with increased afferent drive from the spinal trigeminal nucleus or changes in the ventroposterior thalamus. Thus CPS can result from suppressed inputs from the inhibitory nucleus zona incerta to the posterior thalamus.
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Affiliation(s)
- Radi Masri
- Department of Anatomy, University of Maryland School of Medicine, 20 Penn St., Baltimore, MD 21201, USA
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Chizh BA, Priestley T, Rowbotham M, Schaffler K. Predicting therapeutic efficacy — Experimental pain in human subjects. ACTA ACUST UNITED AC 2009; 60:243-54. [DOI: 10.1016/j.brainresrev.2008.12.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2008] [Indexed: 02/05/2023]
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Abstract
Pain is a highly complex and subjective experience that is not linearly related to the nociceptive input. What is clear from anecdotal reports over the centuries and more recently from animal and human experimentation is that nociceptive information processing and consequent pain perception is subject to significant pro- and anti-nociceptive modulations. These modulations can be initiated reflexively or by contextual manipulations of the pain experience including cognitive and emotional factors. This provides a necessary survival function since it allows the pain experience to be altered according to the situation rather than having pain always dominate. The so-called descending pain modulatory network involving predominantly medial and frontal cortical areas, in combination with specific subcortical and brain stem nuclei appears to be one key system for the endogenous modulation of pain. Furthermore, recent findings from functional and anatomical neuroimaging support the notion that an altered interaction of pro- and anti-nociceptive mechanisms may contribute to the development or maintenance of chronic pain states. Research on the involved circuitry and implemented mechanisms is a major focus of contemporary neuroscientific research in the field of pain and should provide new insights to prevent and treat chronic pain states.
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Affiliation(s)
- Ulrike Bingel
- Department of Neurology, NeuroImage Nord, University Medical Center Hamburg-Eppendorf, Germany; and
- Department of Clinical Neurology, Oxford Centre for Functional MRI on the Brain, Nuffield Department of Anaesthetics, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom,
| | - Irene Tracey
- Department of Clinical Neurology, Oxford Centre for Functional MRI on the Brain, Nuffield Department of Anaesthetics, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom,
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