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Mehsein Z, Kobaïter-Maarrawi S, Samaha H, El Shami M, Albeaini S, Maarrawi J. Right posterior insular epidural stimulation in rats with neuropathic pain induces a frequency-dependent and opioid system-mediated reduction of pain and its comorbid anxiety and depression. Prog Neuropsychopharmacol Biol Psychiatry 2024; 128:110845. [PMID: 37619765 DOI: 10.1016/j.pnpbp.2023.110845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/29/2023] [Accepted: 08/19/2023] [Indexed: 08/26/2023]
Abstract
Neuropathic pain (NP) is a sensory, emotional, and persistent disturbing experience caused by a lesion or disease of the somatosensory system which can lead when chronic to comorbidities such as anxiety and depression. Available treatments (pharmacotherapy, neurostimulation) have partial and unpredictable response; therefore, it seems necessary to find a new therapeutical approach that could alleviate most related symptoms and improve patients 'emotional state'. Posterior Insula seems to be a potential target of neurostimulation for pain relief. However, its effects on pain-related anxiety and depression remain unknown. Using rats with spared nerve injury (SNI), this study aims to elucidate the correlation between NP and anxio-depressive disorders, evaluate potential analgesic, anxiolytic, and antidepressant effects of right posterior insula stimulation (IS) using low (LF-IS, 50 Hz) or high (HF-IS, 150 Hz) frequency and assess endogenous opioid involvement in these effects. Results showed positive correlation between NP, anxiety, and depression. LF-IS reversed anhedonia and despair-like behavior through pain alleviation, whereas HF-IS only reduced anhedonia, all effects involving endogenous opioids. These findings support the link between NP and anxio-depressive disorders. Moreover, IS appears to have analgesic, anxiolytic and antidepressant effects mediated by the endogenous opioid system, making it a promising target for neurostimulation.
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Affiliation(s)
- Zeinab Mehsein
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Sandra Kobaïter-Maarrawi
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon.
| | - Hady Samaha
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Mohamad El Shami
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Sylvana Albeaini
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Joseph Maarrawi
- Laboratory of Research in Neuroscience (LAREN), Pôle Technologie Santé (PTS), Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon; Department of Neurosurgery - Hôtel-Dieu de France Hospital, Beirut, Lebanon
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2
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Peng K, Karunakaran KD, Green S, Borsook D. Machines, mathematics, and modules: the potential to provide real-time metrics for pain under anesthesia. NEUROPHOTONICS 2024; 11:010701. [PMID: 38389718 PMCID: PMC10883389 DOI: 10.1117/1.nph.11.1.010701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/08/2024] [Accepted: 01/16/2024] [Indexed: 02/24/2024]
Abstract
The brain-based assessments under anesthesia have provided the ability to evaluate pain/nociception during surgery and the potential to prevent long-term evolution of chronic pain. Prior studies have shown that the functional near-infrared spectroscopy (fNIRS)-measured changes in cortical regions such as the primary somatosensory and the polar frontal cortices show consistent response to evoked and ongoing pain in awake, sedated, and anesthetized patients. We take this basic approach and integrate it into a potential framework that could provide real-time measures of pain/nociception during the peri-surgical period. This application could have significant implications for providing analgesia during surgery, a practice that currently lacks quantitative evidence to guide patient tailored pain management. Through a simple readout of "pain" or "no pain," the proposed system could diminish or eliminate levels of intraoperative, early post-operative, and potentially, the transition to chronic post-surgical pain. The system, when validated, could also be applied to measures of analgesic efficacy in the clinic.
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Affiliation(s)
- Ke Peng
- University of Manitoba, Department of Electrical and Computer Engineering, Price Faculty of Engineering, Winnipeg, Manitoba, Canada
| | - Keerthana Deepti Karunakaran
- Massachusetts General Hospital, Harvard Medical School, Department of Psychiatry, Boston, Massachusetts, United States
| | - Stephen Green
- Massachusetts Institute of Technology, Department of Mechanical Engineering, Boston, Massachusetts, United States
| | - David Borsook
- Massachusetts General Hospital, Harvard Medical School, Department of Psychiatry, Boston, Massachusetts, United States
- Massachusetts General Hospital, Harvard Medical School, Department of Radiology, Boston, Massachusetts, United States
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3
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Ou M, Chen J, Yang S, Xiao L, Xiong D, Wu S. Rodent models of postherpetic neuralgia: How far have we reached? Front Immunol 2023; 14:1026269. [PMID: 37020565 PMCID: PMC10067614 DOI: 10.3389/fimmu.2023.1026269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 02/22/2023] [Indexed: 04/07/2023] Open
Abstract
Background Induced by varicella zoster virus (VZV), postherpetic neuralgia (PHN) is one of the common complications of herpes zoster (HZ) with refractory pain. Animal models play pivotal roles in disclosing the pain mechanisms and developing effective treatments. However, only a few rodent models focus on the VZV-associated pain and PHN. Objective To summarize the establishment and characteristics of popular PHN rodent models, thus offer bases for the selection and improvement of PHN models. Design In this review, we retrospect two promising PHN rodent models, VZV-induced PHN model and HSV1-induced PHN model in terms of pain-related evaluations, their contributions to PHN pathogenesis and pharmacology. Results Significant difference of two PHN models is the probability of virus proliferation; 2) Most commonly used pain evaluation of PHN model is mechanical allodynia, but pain-induced anxiety and other behaviours are worth noting; 3) From current PHN models, pain mechanisms involve changes in virus gene and host gene expression, neuroimmune-glia interactions and ion channels; 4) antiviral drugs and classical analgesics serve more on the acute stage of herpetic pain. Conclusions Different PHN models assessed by various pain evaluations combine to fulfil more comprehensive understanding of PHN.
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Affiliation(s)
- Mingxi Ou
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Jiamin Chen
- Teaching and Research Group of Biology, Vanke Bilingual School (VBS), Shenzhen, China
| | - Shaomin Yang
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Lizu Xiao
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Donglin Xiong
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Songbin Wu
- Department of Pain Medicine and Shenzhen Municipal Key Laboratory for Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
- *Correspondence: Songbin Wu,
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4
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van Zeeland Y, Schoemaker N. Pain Recognition in Ferrets. Vet Clin North Am Exot Anim Pract 2023; 26:229-243. [PMID: 36402483 DOI: 10.1016/j.cvex.2022.07.011] [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] [Indexed: 06/16/2023]
Abstract
Recognition and accurate assessment of the severity of pain can be challenging in ferrets as they are unable to verbally communicate, and often hide their pain. Pain assessment relies on the assessment of behavioral, physiologic, and other clinical parameters that serve as indirect indicators of pain. Assessment of physiologic and clinical parameters requires handling, which results in changes in these parameters. Behavioral parameters can be assessed less invasively by observing the patient. Due to their nonspecificity, correct interpretation may be challenging. Just as in other species, a grimace scale seems to be the most helpful tool in recognizing pain in ferrets.
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Affiliation(s)
- Yvonne van Zeeland
- Division of Zoological Medicine, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, Utrecht 3584 CM, the Netherlands
| | - Nico Schoemaker
- Division of Zoological Medicine, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, Utrecht 3584 CM, the Netherlands.
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FDG PET Imaging of the Pain Matrix in Neuropathic Pain Model Rats. Biomedicines 2022; 11:biomedicines11010063. [PMID: 36672571 PMCID: PMC9855331 DOI: 10.3390/biomedicines11010063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/03/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Pain is an unpleasant subjective experience that is usually modified by complex multidimensional neuropsychological processes. Increasing numbers of neuroimaging studies in humans have characterized the hierarchical brain areas forming a pain matrix, which is involved in the different dimensions of pain components. Although mechanistic investigations have been performed extensively in rodents, the homologous brain regions involved in the multidimensional pain components have not been fully understood in the rodent brain. Herein, we successfully identified several brain regions activated in response to mechanical allodynia in neuropathic pain rat models using an alternative neuroimaging method based on 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG PET) scanning. Regions such as the medial prefrontal cortex, primary somatosensory cortex hindlimb region, and the centrolateral thalamic nucleus were identified. Moreover, brain activity in these regions was positively correlated with mechanical allodynia-related behavioral changes. These results suggest that FDG PET imaging in neuropathic pain model rats enables the evaluation of regional brain activity encoding the multidimensional pain aspect. It could thus be a fascinating tool to bridge the gap between preclinical and clinical investigations.
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Zhang Z, Gewandter JS, Geha P. Brain Imaging Biomarkers for Chronic Pain. Front Neurol 2022; 12:734821. [PMID: 35046881 PMCID: PMC8763372 DOI: 10.3389/fneur.2021.734821] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/08/2021] [Indexed: 12/14/2022] Open
Abstract
The prevalence of chronic pain has reached epidemic levels. In addition to personal suffering chronic pain is associated with psychiatric and medical co-morbidities, notably substance misuse, and a huge a societal cost amounting to hundreds of billions of dollars annually in medical cost, lost wages, and productivity. Chronic pain does not have a cure or quantitative diagnostic or prognostic tools. In this manuscript we provide evidence that this situation is about to change. We first start by summarizing our current understanding of the role of the brain in the pathogenesis of chronic pain. We particularly focus on the concept of learning in the emergence of chronic pain, and the implication of the limbic brain circuitry and dopaminergic signaling, which underly emotional learning and decision making, in this process. Next, we summarize data from our labs and from other groups on the latest brain imaging findings in different chronic pain conditions focusing on results with significant potential for translation into clinical applications. The gaps in the study of chronic pain and brain imaging are highlighted in throughout the overview. Finally, we conclude by discussing the costs and benefits of using brain biomarkers of chronic pain and compare to other potential markers.
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Affiliation(s)
- Zhengwu Zhang
- Department of Statistics and Operations Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jennifer S Gewandter
- Anesthesiology and Perioperative Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States
| | - Paul Geha
- Department of Psychiatry, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States.,Department of Neurology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, United States.,Del Monte Neuroscience Institute, University of Rochester, Rochester, NY, United States
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7
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Green S, Karunakaran KD, Labadie R, Kussman B, Mizrahi-Arnaud A, Morad AG, Berry D, Zurakowski D, Micheli L, Peng K, Borsook D. fNIRS brain measures of ongoing nociception during surgical incisions under anesthesia. NEUROPHOTONICS 2022; 9:015002. [PMID: 35111876 PMCID: PMC8794294 DOI: 10.1117/1.nph.9.1.015002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Significance: Functional near-infrared spectroscopy (fNIRS) has evaluated pain in awake and anesthetized states. Aim: We evaluated fNIRS signals under general anesthesia in patients undergoing knee surgery for anterior cruciate ligament repair. Approach: Patients were split into groups: those with regional nerve block (NB) and those without (non-NB). Continuous fNIRS measures came from three regions: the primary somatosensory cortex (S1), known to be involved in evaluation of nociception, the lateral prefrontal cortex (BA9), and the polar frontal cortex (BA10), both involved in higher cortical functions (such as cognition and emotion). Results: Our results show three significant differences in fNIRS signals to incision procedures between groups: (1) NB compared with non-NB was associated with a greater net positive hemodynamic response to pain procedures in S1; (2) dynamic correlation between the prefrontal cortex (PreFC) and S1 within 1 min of painful procedures are anticorrelated in NB while positively correlated in non-NB; and (3) hemodynamic measures of activation were similar at two separate time points during surgery (i.e., first and last incisions) in PreFC and S1 but showed significant differences in their overlap. Comparing pain levels immediately after surgery and during discharge from postoperative care revealed no significant differences in the pain levels between NB and non-NB. Conclusion: Our data suggest multiple pain events that occur during surgery using devised algorithms could potentially give a measure of "pain load." This may allow for evaluation of central sensitization (i.e., a heightened state of the nervous system where noxious and non-noxious stimuli is perceived as painful) to postoperative pain levels and the resulting analgesic consumption. This evaluation could potentially predict postsurgical chronic neuropathic pain.
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Affiliation(s)
- Stephen Green
- Boston Children’s Hospital, Harvard Medical School, The Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Keerthana Deepti Karunakaran
- Boston Children’s Hospital, Harvard Medical School, The Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Robert Labadie
- Boston Children’s Hospital, Harvard Medical School, The Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Barry Kussman
- Boston Children’s Hospital, Harvard Medical School, Division of Cardiac Anesthesia, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Arielle Mizrahi-Arnaud
- Boston Children’s Hospital, Harvard Medical School, Division of Perioperative Anesthesia, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Andrea Gomez Morad
- Boston Children’s Hospital, Harvard Medical School, Division of Perioperative Anesthesia, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Delany Berry
- Boston Children’s Hospital, Harvard Medical School, The Center for Pain and the Brain, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - David Zurakowski
- Boston Children’s Hospital, Harvard Medical School, Division of Biostatistics, Department of Anesthesiology, Critical Care and Pain Medicine, Boston, Massachusetts, United States
| | - Lyle Micheli
- Boston Children’s Hospital, Harvard Medical School, Sports Medicine Division, Department of Orthopedic Surgery, Boston, Massachusetts, United States
| | - Ke Peng
- Université de Montréal, Département en Neuroscience, Centre de Recherche du CHUM, Montréal, Quebec, Canada
| | - David Borsook
- Massachusetts General Hospital, Harvard Medical School, Departments of Psychiatry and Radiology, Boston, Massachusetts, United States
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8
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Saber M, Schwabe D, Park HJ, Tessmer J, Khan Z, Ding Y, Robinson M, Hogan QH, Pawela CP. Tonic, Burst, and Burst-Cycle Spinal Cord Stimulation Lead to Differential Brain Activation Patterns as Detected by Functional Magnetic Resonance Imaging. Neuromodulation 2022; 25:53-63. [PMID: 35041588 DOI: 10.1111/ner.13460] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 04/05/2021] [Accepted: 04/26/2021] [Indexed: 01/17/2023]
Abstract
OBJECTIVE The objective of this preclinical study was to examine the responses of the brain to noxious stimulation in the presence and absence of different modes of spinal cord stimulation (SCS) using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI). MATERIALS AND METHODS Sprague-Dawley rats were randomized to groups based on the mode of SCS delivered which included tonic stimulation (n = 27), burst stimulation (n = 30), and burst-cycle stimulation (n = 29). The control (sham) group (n = 28) received no SCS. The SCS electrode was inserted between T10 and T12 spinal levels prior to fMRI session. The experimental protocol for fMRI acquisition consisted of an initial noxious stimulation phase, a treatment phase wherein the SCS was turned on concurrently with noxious stimulation, and a residual effect phase wherein the noxious stimulation alone was turned on. The responses were statistically analyzed through paired t-test and the results were presented as z-scores for the quantitative analysis of the fMRI data. RESULTS The treatment with different SCS modes attenuated the BOLD brain responses to noxious hindlimb stimulation. The tonic, burst, and burst-cycle SCS treatment attenuated BOLD responses in the caudate putamen (CPu), insula (In), and secondary somatosensory cortex (S2). There was little to no corresponding change in sham control in these three regions. The burst and burst-cycle SCS demonstrated greater attenuation of BOLD signals in CPu, In, and S2 compared to tonic stimulation. CONCLUSION The high-resolution fMRI study using a rat model demonstrated the potential of different SCS modes to act on several pain-matrix-related regions of the brain in response to noxious stimulation. The burst and burst-cycle SCS exhibited greater brain activity reduction in response to noxious hindlimb stimulation in the caudate putamen, insula, and secondary somatosensory cortex compared to tonic stimulation.
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Affiliation(s)
- Mohammad Saber
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - David Schwabe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - John Tessmer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Zan Khan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Yujie Ding
- University of Kentucky College of Medicine, Lexington, KY, USA
| | - Maraika Robinson
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
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9
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Lang VA, Lundh T, Ortiz-Catalan M. Mathematical and computational models for pain: a systematic review. PAIN MEDICINE 2021; 22:2806-2817. [PMID: 34051102 PMCID: PMC8665994 DOI: 10.1093/pm/pnab177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE There is no single prevailing theory of pain that explains its origin, qualities, and alleviation. Although many studies have investigated various molecular targets for pain management, few have attempted to examine the etiology or working mechanisms of pain through mathematical or computational model development. In this systematic review, we identified and classified mathematical and computational models for characterizing pain. METHODS The databases queried were Science Direct and PubMed, yielding 560 articles published prior to January 1st, 2020. After screening for inclusion of mathematical or computational models of pain, 31 articles were deemed relevant. RESULTS Most of the reviewed articles utilized classification algorithms to categorize pain and no-pain conditions. We found the literature heavily focused on the application of existing models or machine learning algorithms to identify the presence or absence of pain, rather than to explore features of pain that may be used for diagnostics and treatment. CONCLUSIONS Although understudied, the development of mathematical models may augment the current understanding of pain by providing directions for testable hypotheses of its underlying mechanisms. Additional focus is needed on developing models that seek to understand the underlying mechanisms of pain, as this could potentially lead to major breakthroughs in its treatment.
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Affiliation(s)
- Victoria Ashley Lang
- Center for Bionics and Pain Research, Sweden.,Department of Electrical Engineering, Chalmers University of Technology, Sweden
| | - Torbjörn Lundh
- Center for Bionics and Pain Research, Sweden.,Department of Mathematical Sciences, Chalmers University of Technology, Sweden.,Department of Mathematical Sciences, University of Gothenburg, Sweden
| | - Max Ortiz-Catalan
- Center for Bionics and Pain Research, Sweden.,Department of Electrical Engineering, Chalmers University of Technology, Sweden.,Operational Area 3, Sahlgrenska University Hospital, Sweden.,Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden
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10
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Abstract
Human and animal imaging studies demonstrated that chronic pain profoundly alters the structure and the functionality of several brain regions. In this article, we conducted a longitudinal and multimodal study to assess how chronic pain affects the brain. Using the spared nerve injury model which promotes both long-lasting mechanical and thermal allodynia/hyperalgesia but also pain-associated comorbidities, we showed that neuropathic pain deeply modified the intrinsic organization of the brain functional network 1 and 2 months after injury. We found that both functional metrics and connectivity of the part A of the retrosplenial granular cortex (RSgA) were significantly correlated with the development of neuropathic pain behaviours. In addition, we found that the functional RSgA connectivity to the subiculum and the prelimbic system are significantly increased in spared nerve injury animals and correlated with peripheral pain thresholds. These brain regions were previously linked to the development of comorbidities associated with neuropathic pain. Using a voxel-based morphometry approach, we showed that neuropathic pain induced a significant increase of the gray matter concentration within the RSgA, associated with a significant activation of both astrocytes and microglial cells. Together, functional and morphological imaging metrics of the RSgA could be used as a predictive biomarker of neuropathic pain.
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Abstract
The poor translational record of pain research has suggested to some observers that species differences in pain biology might be to blame. In this review, I consider the evidence for species similarity and differences in the pain research literature. Impressive feats of translation have been demonstrated in relation to certain genetic effects, social modulation of pain and pain memory. The degree to which pain biology in rodents predicts pain biology in humans has important implications both for evolutionary accounts of pain, but also the success of analgesic drug development going forward. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
- Jeffrey S Mogil
- Departments of Psychology and Anesthesia, McGill University, Montreal, Quebec, Canada H3A 1B1
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12
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Neuroimaging of pain in animal models: a review of recent literature. Pain Rep 2019; 4:e732. [PMID: 31579844 PMCID: PMC6728006 DOI: 10.1097/pr9.0000000000000732] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/06/2019] [Accepted: 02/12/2019] [Indexed: 01/19/2023] Open
Abstract
Neuroimaging of pain in animals allows us to better understand mechanisms of pain processing and modulation. In this review, we discuss recently published brain imaging studies in rats, mice, and monkeys, including functional magnetic resonance imaging (MRI), manganese-enhanced MRI, positron emission tomography, and electroencephalography. We provide an overview of innovations and limitations in neuroimaging techniques, as well as results of functional brain imaging studies of pain from January 1, 2016, to October 10, 2018. We then discuss how future investigations can address some bias and gaps in the field. Despite the limitations of neuroimaging techniques, the 28 studies reinforced that transition from acute to chronic pain entails considerable changes in brain function. Brain activations in acute pain were in areas more related to the sensory aspect of noxious stimulation, including primary somatosensory cortex, insula, cingulate cortex, thalamus, retrosplenial cortex, and periaqueductal gray. Pharmacological and nonpharmacological treatments modulated these brain regions in several pain models. On the other hand, in chronic pain models, brain activity was observed in regions commonly associated with emotion and motivation, including prefrontal cortex, anterior cingulate cortex, hippocampus, amygdala, basal ganglia, and nucleus accumbens. Neuroimaging of pain in animals holds great promise for advancing our knowledge of brain function and allowing us to expand human subject research. Additional research is needed to address effects of anesthesia, analysis approaches, sex bias and omission, and potential effects of development and aging.
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13
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Longitudinal resting-state functional magnetic resonance imaging in a mouse model of metastatic bone cancer reveals distinct functional reorganizations along a developing chronic pain state. Pain 2019; 159:719-727. [PMID: 29319607 DOI: 10.1097/j.pain.0000000000001148] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Functional neuroimaging has emerged as attractive option for characterizing pain states complementing behavioral readouts or clinical assessment. In particular, resting-state functional magnetic resonance imaging (rs-fMRI) enables monitoring of functional adaptations across the brain, for example, in response to chronic nociceptive input. We have used rs-fMRI in a mouse model of chronic pain from breast cancer-derived tibial bone metastases to identify pain-induced alterations in functional connectivity. Combined assessment of behavioral readouts allowed for defining a trajectory as model function for extracting pain-specific functional connectivity changes from the fMRI data reflective of a chronic pain state. Cingulate and prefrontal cortices as well as the ventral striatum were identified as predominantly affected regions, in line with findings from clinical and preclinical studies. Inhibition of the peripheral bone remodeling processes by antiosteolytic therapy led to a reduction of pain-induced network alterations, emphasizing the specificity of the functional readouts for a developing chronic pain state.
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14
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Abstract
Pain has a strong emotional component and is defined by its unpleasantness. Chronic pain represents a complex disorder with anxio-depressive symptoms and cognitive deficits. Underlying mechanisms are still not well understood but an important role for interactions between prefrontal cortical areas and subcortical limbic structures has emerged. Evidence from preclinical studies in the rodent brain suggests that neuroplastic changes in prefrontal (anterior cingulate, prelimbic and infralimbic) cortical and subcortical (amygdala and nucleus accumbens) brain areas and their interactions (corticolimbic circuitry) contribute to the complexity and persistence of pain and may be predetermining factors as has been proposed in recent human neuroimaging studies.
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Affiliation(s)
- Jeremy M Thompson
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, United States
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, United States; Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
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15
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Boll S, Almeida de Minas A, Raftogianni A, Herpertz S, Grinevich V. Oxytocin and Pain Perception: From Animal Models to Human Research. Neuroscience 2018; 387:149-161. [DOI: 10.1016/j.neuroscience.2017.09.041] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/14/2017] [Accepted: 09/24/2017] [Indexed: 11/24/2022]
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16
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Mouse fMRI under ketamine and xylazine anesthesia: Robust contralateral somatosensory cortex activation in response to forepaw stimulation. Neuroimage 2018; 177:30-44. [DOI: 10.1016/j.neuroimage.2018.04.062] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/24/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
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17
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Abstract
The mechanisms by which noxious stimuli produce the sensation of pain in animals are complex. Noxious stimuli are transduced at the periphery and transmitted to the CNS, where this information is subject to considerable modulation. Finally, the information is projected to the brain where it is perceived as pain. Additionally, plasticity can develop in the pain pathway and hyperalgesia and allodynia may develop through sensitisation both peripherally and centrally. A large number of different ion channels, receptors, and cell types are involved in pain perception, and it is hoped that through a better understanding of these, new and refined treatments for pain will result.
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Affiliation(s)
- A Bell
- School of Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK.
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18
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Somatosensory BOLD fMRI reveals close link between salient blood pressure changes and the murine neuromatrix. Neuroimage 2018; 172:562-574. [DOI: 10.1016/j.neuroimage.2018.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 12/11/2022] Open
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19
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Upadhyay J, Geber C, Hargreaves R, Birklein F, Borsook D. A critical evaluation of validity and utility of translational imaging in pain and analgesia: Utilizing functional imaging to enhance the process. Neurosci Biobehav Rev 2018; 84:407-423. [PMID: 28807753 PMCID: PMC5729102 DOI: 10.1016/j.neubiorev.2017.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/22/2017] [Accepted: 08/04/2017] [Indexed: 02/07/2023]
Abstract
Assessing clinical pain and metrics related to function or quality of life predominantly relies on patient reported subjective measures. These outcome measures are generally not applicable to the preclinical setting where early signs pointing to analgesic value of a therapy are sought, thus introducing difficulties in animal to human translation in pain research. Evaluating brain function in patients and respective animal model(s) has the potential to characterize mechanisms associated with pain or pain-related phenotypes and thereby provide a means of laboratory to clinic translation. This review summarizes the progress made towards understanding of brain function in clinical and preclinical pain states elucidated using an imaging approach as well as the current level of validity of translational pain imaging. We hypothesize that neuroimaging can describe the central representation of pain or pain phenotypes and yields a basis for the development and selection of clinically relevant animal assays. This approach may increase the probability of finding meaningful new analgesics that can help satisfy the significant unmet medical needs of patients.
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Affiliation(s)
| | - Christian Geber
- Department of Neurology, University Medical Centre Mainz, Mainz, Germany; DRK Schmerz-Zentrum Mainz, Mainz, Germany
| | - Richard Hargreaves
- Center for Pain and the Brain, United States; Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston Harvard Medical School, Boston, MA 02115, United States
| | - Frank Birklein
- Department of Neurology, University Medical Centre Mainz, Mainz, Germany
| | - David Borsook
- Center for Pain and the Brain, United States; Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston Harvard Medical School, Boston, MA 02115, United States.
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20
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Bajic D, Craig MM, Mongerson CRL, Borsook D, Becerra L. Identifying Rodent Resting-State Brain Networks with Independent Component Analysis. Front Neurosci 2017; 11:685. [PMID: 29311770 PMCID: PMC5733053 DOI: 10.3389/fnins.2017.00685] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/22/2017] [Indexed: 01/08/2023] Open
Abstract
Rodent models have opened the door to a better understanding of the neurobiology of brain disorders and increased our ability to evaluate novel treatments. Resting-state functional magnetic resonance imaging (rs-fMRI) allows for in vivo exploration of large-scale brain networks with high spatial resolution. Its application in rodents affords researchers a powerful translational tool to directly assess/explore the effects of various pharmacological, lesion, and/or disease states on known neural circuits within highly controlled settings. Integration of animal and human research at the molecular-, systems-, and behavioral-levels using diverse neuroimaging techniques empowers more robust interrogations of abnormal/ pathological processes, critical for evolving our understanding of neuroscience. We present a comprehensive protocol to evaluate resting-state brain networks using Independent Component Analysis (ICA) in rodent model. Specifically, we begin with a brief review of the physiological basis for rs-fMRI technique and overview of rs-fMRI studies in rodents to date, following which we provide a robust step-by-step approach for rs-fMRI investigation including data collection, computational preprocessing, and brain network analysis. Pipelines are interwoven with underlying theory behind each step and summarized methodological considerations, such as alternative methods available and current consensus in the literature for optimal results. The presented protocol is designed in such a way that investigators without previous knowledge in the field can implement the analysis and obtain viable results that reliably detect significant differences in functional connectivity between experimental groups. Our goal is to empower researchers to implement rs-fMRI in their respective fields by incorporating technical considerations to date into a workable methodological framework.
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Affiliation(s)
- Dusica Bajic
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Michael M Craig
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
| | - Chandler R L Mongerson
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
| | - David Borsook
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Lino Becerra
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
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21
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Abstract
Neuroimaging studies of patients with chronic pain have shown that neurotransmitter abnormalities, including increases in glutamate and decreases in GABA, could be responsible for the cortical hyperactivity and hyperalgesia/allodynia observed in some pain conditions. These finding are particularly evident in the insula, a brain region known to play a role in both the sensory-discriminative and the affective-motivational aspects of pain processing. However, clinical studies are not entirely able to determine the directionality of these findings, nor whether they are causal or epiphenomenon. Thus, a set of animal studies was performed to determine whether alterations in glutamate and GABA are the result of injury, the cause of augmented pain processing, or both. Compared with controls, the excitatory neurotransmitters glutamate and aspartate are significantly higher in the rat insula after chronic constriction injury of the sciatic nerve (CCI). The CCI also produced significant increases in allodynia (mechanical and cold), thermal hyperalgesia, and nociceptive aversiveness. Unilateral microinjection of ionotropic glutamate receptor antagonists restored these nociceptive behaviors to preinjury values. Increasing endogenous levels of GABA or enhancing signaling at inhibitory glycinergic receptors had similar effects as the glutamate receptor antagonists. In naive rats, increasing endogenous levels of glutamate, decreasing endogenous levels of GABA, or blocking strychnine-sensitive glycine receptors in the insula significantly increased thermal hyperalgesia and mechanical allodynia. These data support the hypothesis that an altered balance of excitatory and inhibitory neurotransmitters in brain regions such as the insula occurs in chronic pain states and leads to augmented central pain processing and increased pain sensitivity.
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22
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Frölich MA, Banks C, Ness TJ. The Effect of Sedation on Cortical Activation: A Randomized Study Comparing the Effects of Sedation With Midazolam, Propofol, and Dexmedetomidine on Auditory Processing. Anesth Analg 2017; 124:1603-1610. [PMID: 28333707 DOI: 10.1213/ane.0000000000002021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Every day, millions of people undergo surgical procedures facilitated by anesthesia. Yet, there is no clinically accepted measure to predict the effects of sedation or anesthesia on the central nervous system. Auditory brain activation may provide an objective and quantifiable method to measure of the effects of sedation on neuronal processing. METHODS This is a randomized clinical trial. Forty-eight healthy volunteers were randomly assigned to receive 1 of 3 sedative drugs (midazolam [n = 11], propofol [n = 12], or dexmedetomidine [n = 12]) at a concentration adjusted to achieve mild sedation by self-rating, or to a no-drug control group (n = 13). Participants underwent functional magnetic resonance imaging while listening to music in a 5-minute block design experiment. We tested the hypothesis that mild sedation changes the magnitude or extent of cortical activation of an auditory stimulus. RESULTS We observed a significant reduction in auditory activation in both the dexmedetomidine (P = .001) and midazolam (P = .029) but not the propofol group (P = .619) when compared with saline control. CONCLUSIONS Our findings indicate that, compared with saline control, there is a significant reduction of brain activation in the auditory cortex in response to midazolam and dexmedetomidine but not propofol when given at mildly sedative doses. This method serves as a novel approach to quantify the effects of sedative agents in an objective fashion.
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Affiliation(s)
- Michael A Frölich
- From the *Department of Anesthesiology, University of Alabama at Birmingham (UAB), Birmingham, Alabama; and †Emory Health Care System, Atlanta, Georgia
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23
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Devonshire IM, Burston JJ, Xu L, Lillywhite A, Prior MJ, Watson DJG, Greenspon CM, Iwabuchi SJ, Auer DP, Chapman V. Manganese-enhanced magnetic resonance imaging depicts brain activity in models of acute and chronic pain: A new window to study experimental spontaneous pain? Neuroimage 2017. [PMID: 28633971 PMCID: PMC5607296 DOI: 10.1016/j.neuroimage.2017.06.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Application of functional imaging techniques to animal models is vital to understand pain mechanisms, but is often confounded by the need to limit movement artefacts with anaesthesia, and a focus on evoked responses rather than clinically relevant spontaneous pain and related hyperalgesia. The aim of the present study was to investigate the potential of manganese-enhanced magnetic resonance imaging (MEMRI) to measure neural responses during on-going pain that underpins hyperalgesia in pre-clinical models of nociception. As a proof of concept that MEMRI is sensitive to the neural activity of spontaneous, intermittent behaviour, we studied a separate positive control group undergoing a voluntary running wheel experiment. In the pain models, pain behaviour (weight bearing asymmetry and hindpaw withdrawal thresholds (PWTs)) was measured at baseline and following either intra-articular injection of nerve growth factor (NGF, 10µg/50µl; acute pain model, n=4 rats per group), or the chondrocyte toxin monosodium iodoacetate (MIA, 1mg/50µl; chronic model, n=8 rats per group), or control injection. Separate groups of rats underwent a voluntary wheel running protocol (n=8 rats per group). Rats were administered with paramagnetic ion Mn2+ as soluble MnCl2 over seven days (subcutaneous osmotic pump) to allow cumulative activity-dependent neural accumulation in the models of pain, or over a period of running. T1-weighted MR imaging at 7T was performed under isoflurane anaesthesia using a receive-only rat head coil in combination with a 72mm volume coil for excitation. The pain models resulted in weight bearing asymmetry (NGF: 20.0 ± 5.2%, MIA: 15 ± 3%), and a reduction in PWT in the MIA model (8.3 ± 1.5g) on the final day of assessment before undergoing MR imaging. Voxel-wise and region-based analysis of MEMRI data did not identify group differences in T1 signal. However, MnCl2 accumulation in the VTA, right Ce amygdala, and left cingulate was negatively correlated with pain responses (greater differences in weight bearing), similarly MnCl2 accumulation was reduced in the VTA in line with hyperalgesia (lower PWTs), which suggests reduced regional activation as a result of the intensity and duration of pain experienced during the 7 days of MnCl2 exposure. Motor cortex T1-weighted signal increase was associated with the distance ran in the wheel running study, while no between group difference was seen. Our data suggest that on-going pain related signal changes identified using MEMRI offers a new window to study the neural underpinnings of spontaneous pain in rats.
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Affiliation(s)
- I M Devonshire
- Arthritis Research UK Pain Centre, University of Nottingham, UK; School of Life Sciences, University of Nottingham, UK
| | - J J Burston
- Arthritis Research UK Pain Centre, University of Nottingham, UK; School of Life Sciences, University of Nottingham, UK
| | - L Xu
- Arthritis Research UK Pain Centre, University of Nottingham, UK; School of Life Sciences, University of Nottingham, UK
| | - A Lillywhite
- Arthritis Research UK Pain Centre, University of Nottingham, UK; School of Life Sciences, University of Nottingham, UK
| | - M J Prior
- Medical Imaging Unit, School of Medicine, University of Nottingham, UK
| | - D J G Watson
- School of Life Sciences, University of Nottingham, UK
| | - C M Greenspon
- School of Life Sciences, University of Nottingham, UK
| | - S J Iwabuchi
- Medical Imaging Unit, School of Medicine, University of Nottingham, UK; Neuroradiology, Nottingham University Hospitals Trust, Nottingham NG7 2UH, UK
| | - D P Auer
- Arthritis Research UK Pain Centre, University of Nottingham, UK; Medical Imaging Unit, School of Medicine, University of Nottingham, UK; Neuroradiology, Nottingham University Hospitals Trust, Nottingham NG7 2UH, UK
| | - V Chapman
- Arthritis Research UK Pain Centre, University of Nottingham, UK; School of Life Sciences, University of Nottingham, UK.
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24
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Lin YT, Liu HL, Day YJ, Chang CC, Hsu PH, Chen JC. Activation of NPFFR2 leads to hyperalgesia through the spinal inflammatory mediator CGRP in mice. Exp Neurol 2017; 291:62-73. [DOI: 10.1016/j.expneurol.2017.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/25/2017] [Accepted: 02/01/2017] [Indexed: 01/22/2023]
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25
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Verriotis M, Chang P, Fitzgerald M, Fabrizi L. The development of the nociceptive brain. Neuroscience 2016; 338:207-219. [DOI: 10.1016/j.neuroscience.2016.07.026] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 06/28/2016] [Accepted: 07/16/2016] [Indexed: 12/20/2022]
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26
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Pawela CP, Kramer JM, Hogan QH. Dorsal root ganglion stimulation attenuates the BOLD signal response to noxious sensory input in specific brain regions: Insights into a possible mechanism for analgesia. Neuroimage 2016; 147:10-18. [PMID: 27876655 DOI: 10.1016/j.neuroimage.2016.11.046] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/26/2016] [Accepted: 11/17/2016] [Indexed: 12/26/2022] Open
Abstract
Targeted dorsal root ganglion (DRG) electrical stimulation (i.e. ganglionic field stimulation - GFS) is an emerging therapeutic approach to alleviate chronic pain. Here we describe blood oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to noxious hind-limb stimulation in a rat model that replicates clinical GFS using an electrode implanted adjacent to the DRG. Acute noxious sensory stimulation in the absence of GFS caused robust BOLD fMRI response in brain regions previously associated with sensory and pain-related response, such as primary/secondary somatosensory cortex, retrosplenial granular cortex, thalamus, caudate putamen, nucleus accumbens, globus pallidus, and amygdala. These regions differentially demonstrated either positive or negative correlation to the acute noxious stimulation paradigm, in agreement with previous rat fMRI studies. Therapeutic-level GFS significantly attenuated the global BOLD response to noxious stimulation in these regions. This BOLD signal attenuation persisted for 20minutes after the GFS was discontinued. Control experiments in sham-operated animals showed that the attenuation was not due to the effect of repetitive noxious stimulation. Additional control experiments also revealed minimal BOLD fMRI response to GFS at therapeutic intensity when presented in a standard block-design paradigm. High intensity GFS produced a BOLD signal map similar to acute noxious stimulation when presented in a block-design. These findings are the first to identify the specific brain region responses to neuromodulation at the DRG level and suggest possible mechanisms for GFS-induced treatment of chronic pain.
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Affiliation(s)
- Christopher P Pawela
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | | | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
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27
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Kussman BD, Aasted CM, Yücel MA, Steele SC, Alexander ME, Boas DA, Borsook D, Becerra L. Capturing Pain in the Cortex during General Anesthesia: Near Infrared Spectroscopy Measures in Patients Undergoing Catheter Ablation of Arrhythmias. PLoS One 2016; 11:e0158975. [PMID: 27415436 PMCID: PMC4944937 DOI: 10.1371/journal.pone.0158975] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/25/2016] [Indexed: 12/20/2022] Open
Abstract
The predictability of pain makes surgery an ideal model for the study of pain and the development of strategies for analgesia and reduction of perioperative pain. As functional near-infrared spectroscopy reproduces the known functional magnetic resonance imaging activations in response to a painful stimulus, we evaluated the feasibility of functional near-infrared spectroscopy to measure cortical responses to noxious stimulation during general anesthesia. A multichannel continuous wave near-infrared imager was used to measure somatosensory and frontal cortical activation in patients undergoing catheter ablation of arrhythmias under general anesthesia. Anesthetic technique was standardized and intraoperative NIRS signals recorded continuously with markers placed in the data set for the timing and duration of each cardiac ablation event. Frontal cortical signals only were suitable for analysis in five of eight patients studied (mean age 14 ± 1 years, weight 66.7 ± 17.6 kg, 2 males). Thirty ablative lesions were recorded for the five patients. Radiofrequency or cryoablation was temporally associated with a hemodynamic response function in the frontal cortex characterized by a significant decrease in oxyhemoglobin concentration (paired t-test, p<0.05) with the nadir occurring in the period 4 to 6 seconds after application of the ablative lesion. Cortical signals produced by catheter ablation of arrhythmias in patients under general anesthesia mirrored those seen with noxious stimulation in awake, healthy volunteers, during sedation for colonoscopy, and functional Magnetic Resonance Imaging activations in response to pain. This study demonstrates the feasibility and potential utility of functional near-infrared spectroscopy as an objective measure of cortical activation under general anesthesia.
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Affiliation(s)
- Barry D. Kussman
- Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Christopher M. Aasted
- Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Meryem A. Yücel
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarah C. Steele
- Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mark E. Alexander
- Department of Cardiology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - David A. Boas
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - David Borsook
- Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lino Becerra
- Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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28
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Abaei M, Sagar DR, Stockley EG, Spicer CH, Prior M, Chapman V, Auer DP. Neural correlates of hyperalgesia in the monosodium iodoacetate model of osteoarthritis pain. Mol Pain 2016; 12:12/0/1744806916642445. [PMID: 27068285 PMCID: PMC4956384 DOI: 10.1177/1744806916642445] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/07/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The mechanisms driving osteoarthritic pain remain poorly understood, but there is increasing evidence for a role of the central nervous system in the chronification of pain. We used functional magnetic resonance imaging to investigate the influence of a model of unilateral knee osteoarthritis on nociceptive processing. RESULTS Four to five weeks post intra-articular injection of monosodium iodoacetate (MIA, 1 mg) into the left knee, Sprague Dawley rats were anesthetized for functional magnetic resonance imaging studies to characterize the neural response to a noxious stimulus (intra-articular capsaicin injection). In a two-arm cross-over design, 5 µM/50 µl capsaicin was injected into either the left knee (n = 8, CAPS-MIA) or right control knee (n = 8, CAPS-CON), preceded by contralateral vehicle (SAL) injection. To assess neural correlates of mechanical hyperalgesia, hindpaws were stimulated with von Frey hairs (8 g: MIA; 15 g: control knee, based on behavioral withdrawal responses). The CAPS-MIA group exhibited significant activation of the periaqueductal gray, unilateral thalamus and bilateral mensencephalon, superior-colliculus, and hippocampus, with no significant activation in the other groups/conditions. Capsaicin injection increased functional connectivity in the mid-brain network and mediodorsal thalamic nucleus, hippocampus, and globus pallidus, which was significantly stronger in CAPS-MIA compared to CAPS-CON groups. Mechanical stimulation of the hyperalgesic (ipsilateral to MIA knee) and normalgesic (contralateral) hindpaws evoked qualitatively different brain activation with more widespread brainstem and anterior cingulate (ACC) activation when stimulating the hyperalgesic paw, and clearer frontal sensory activation from the normalgesic paw. CONCLUSIONS We provide evidence for modulation of nociceptive processing in a chronic knee osteoarthritis pain model with stronger brain activation and alteration of brain networks induced by the pro-nociceptive stimulus. We also report a shift to a medial pain activation pattern following stimulation of the hyperalgesic hindpaw. Taken together, our data support altered neural pain processing as a result of peripheral and central pain sensitization in this model.
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Affiliation(s)
- Maryam Abaei
- Radiological Sciences, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Devi R Sagar
- Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Elizabeth G Stockley
- Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Clare H Spicer
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Malcolm Prior
- Medical Imaging Unit, School of Medicine, University of Nottingham, Nottingham, UK
| | - Victoria Chapman
- Arthritis Research UK Pain Centre, University of Nottingham, Nottingham, UK School of Life Sciences, 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 Medical Imaging Unit, School of Medicine, University of Nottingham, Nottingham, UK
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29
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Reimann HM, Hentschel J, Marek J, Huelnhagen T, Todiras M, Kox S, Waiczies S, Hodge R, Bader M, Pohlmann A, Niendorf T. Normothermic Mouse Functional MRI of Acute Focal Thermostimulation for Probing Nociception. Sci Rep 2016; 6:17230. [PMID: 26821826 PMCID: PMC4731789 DOI: 10.1038/srep17230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 10/27/2015] [Indexed: 11/30/2022] Open
Abstract
Combining mouse genomics and functional magnetic resonance imaging (fMRI) provides a promising tool to unravel the molecular mechanisms of chronic pain. Probing murine nociception via the blood oxygenation level-dependent (BOLD) effect is still challenging due to methodological constraints. Here we report on the reproducible application of acute noxious heat stimuli to examine the feasibility and limitations of functional brain mapping for central pain processing in mice. Recent technical and procedural advances were applied for enhanced BOLD signal detection and a tight control of physiological parameters. The latter includes the development of a novel mouse cradle designed to maintain whole-body normothermia in anesthetized mice during fMRI in a way that reflects the thermal status of awake, resting mice. Applying mild noxious heat stimuli to wildtype mice resulted in highly significant BOLD patterns in anatomical brain structures forming the pain matrix, which comprise temporal signal intensity changes of up to 6% magnitude. We also observed sub-threshold correlation patterns in large areas of the brain, as well as alterations in mean arterial blood pressure (MABP) in response to the applied stimulus.
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Affiliation(s)
- Henning Matthias Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jan Hentschel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jaroslav Marek
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Mihail Todiras
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Stefanie Kox
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Russ Hodge
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Michael Bader
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany.,Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Berlin, Germany
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30
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Niendorf T, Pohlmann A, Reimann HM, Waiczies H, Peper E, Huelnhagen T, Seeliger E, Schreiber A, Kettritz R, Strobel K, Ku MC, Waiczies S. Advancing Cardiovascular, Neurovascular, and Renal Magnetic Resonance Imaging in Small Rodents Using Cryogenic Radiofrequency Coil Technology. Front Pharmacol 2015; 6:255. [PMID: 26617515 PMCID: PMC4642111 DOI: 10.3389/fphar.2015.00255] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/19/2015] [Indexed: 12/11/2022] Open
Abstract
Research in pathologies of the brain, heart and kidney have gained immensely from the plethora of studies that have helped shape new methods in magnetic resonance (MR) for characterizing preclinical disease models. Methodical probing into preclinical animal models by MR is invaluable since it allows a careful interpretation and extrapolation of data derived from these models to human disease. In this review we will focus on the applications of cryogenic radiofrequency (RF) coils in small animal MR as a means of boosting image quality (e.g., by supporting MR microscopy) and making data acquisition more efficient (e.g., by reducing measuring time); both being important constituents for thorough investigational studies on animal models of disease. This review attempts to make the (bio)medical imaging, molecular medicine, and pharmaceutical communities aware of this productive ferment and its outstanding significance for anatomical and functional MR in small rodents. The goal is to inspire a more intense interdisciplinary collaboration across the fields to further advance and progress non-invasive MR methods that ultimately support thorough (patho)physiological characterization of animal disease models. In this review, current and potential future applications for the RF coil technology in cardiovascular, neurovascular, and renal disease will be discussed.
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Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
- German Centre for Cardiovascular ResearchBerlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
| | - Henning M. Reimann
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
| | | | - Eva Peper
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
| | - Erdmann Seeliger
- Center for Cardiovascular Research, Institute of Physiology, Charité—Universitätsmedizin BerlinBerlin, Germany
| | - Adrian Schreiber
- Clinic for Nephrology and Intensive Care Medicine, Charité Medical Faculty and Experimental and Clinical Research CenterBerlin, Germany
| | - Ralph Kettritz
- Clinic for Nephrology and Intensive Care Medicine, Charité Medical Faculty and Experimental and Clinical Research CenterBerlin, Germany
| | | | - Min-Chi Ku
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlin, Germany
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Jonckers E, Shah D, Hamaide J, Verhoye M, Van der Linden A. The power of using functional fMRI on small rodents to study brain pharmacology and disease. Front Pharmacol 2015; 6:231. [PMID: 26539115 PMCID: PMC4612660 DOI: 10.3389/fphar.2015.00231] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/28/2015] [Indexed: 12/23/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest. In addition, fMRI techniques allow one to dissect how specific modifications (e.g., treatment, lesion etc.) modulate the functioning of specific brain areas (st-fMRI, phMRI) and how functional connectivity (rsfMRI) between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with several methodological considerations.
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Affiliation(s)
- Elisabeth Jonckers
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp Antwerp, Belgium
| | - Disha Shah
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp Antwerp, Belgium
| | - Julie Hamaide
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp Antwerp, Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp Antwerp, Belgium
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Guillot M, Chartrand G, Chav R, Rousseau J, Beaudoin JF, Martel-Pelletier J, Pelletier JP, Lecomte R, de Guise JA, Troncy E. [18F]-fluorodeoxyglucose positron emission tomography of the cat brain: A feasibility study to investigate osteoarthritis-associated pain. Vet J 2015; 204:299-303. [DOI: 10.1016/j.tvjl.2015.03.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/03/2015] [Accepted: 03/22/2015] [Indexed: 11/28/2022]
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Borsook D, Hargreaves R, Bountra C, Porreca F. Lost but making progress--Where will new analgesic drugs come from? Sci Transl Med 2015; 6:249sr3. [PMID: 25122640 DOI: 10.1126/scitranslmed.3008320] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is a critical need for effective new pharmacotherapies for pain. The paucity of new drugs successfully reaching the clinic calls for a reassessment of current analgesic drug discovery approaches. Many points early in the discovery process present significant hurdles, making it critical to exploit advances in pain neurobiology to increase the probability of success. In this review, we highlight approaches that are being pursued vigorously by the pain community for drug discovery, including innovative preclinical pain models, insights from genetics, mechanistic phenotyping of pain patients, development of biomarkers, and emerging insights into chronic pain as a disorder of both the periphery and the brain. Collaborative efforts between pharmaceutical, academic, and public entities to advance research in these areas promise to de-risk potential targets, stimulate investment, and speed evaluation and development of better pain therapies.
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Affiliation(s)
- David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Richard Hargreaves
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Chas Bountra
- Department of Clinical Medicine, University of Oxford, Oxford OX1 2JD, UK
| | - Frank Porreca
- Center for Pain and the Brain and Department of Pharmacology, University of Arizona, Tucson, AZ 85724, USA.
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Yee JR, Kenkel W, Caccaviello JC, Gamber K, Simmons P, Nedelman M, Kulkarni P, Ferris CF. Identifying the integrated neural networks involved in capsaicin-induced pain using fMRI in awake TRPV1 knockout and wild-type rats. Front Syst Neurosci 2015; 9:15. [PMID: 25745388 PMCID: PMC4333803 DOI: 10.3389/fnsys.2015.00015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/31/2015] [Indexed: 12/18/2022] Open
Abstract
In the present study, we used functional MRI in awake rats to investigate the pain response that accompanies intradermal injection of capsaicin into the hindpaw. To this end, we used BOLD imaging together with a 3D segmented, annotated rat atlas and computational analysis to identify the integrated neural circuits involved in capsaicin-induced pain. The specificity of the pain response to capsaicin was tested in a transgenic model that contains a biallelic deletion of the gene encoding for the transient receptor potential cation channel subfamily V member 1 (TRPV1). Capsaicin is an exogenous ligand for the TRPV1 receptor, and in wild-type rats, activated the putative pain neural circuit. In addition, capsaicin-treated wild-type rats exhibited activation in brain regions comprising the Papez circuit and habenular system, systems that play important roles in the integration of emotional information, and learning and memory of aversive information, respectively. As expected, capsaicin administration to TRPV1-KO rats failed to elicit the robust BOLD activation pattern observed in wild-type controls. However, the intradermal injection of formalin elicited a significant activation of the putative pain pathway as represented by such areas as the anterior cingulate, somatosensory cortex, parabrachial nucleus, and periaqueductal gray. Notably, comparison of neural responses to capsaicin in wild-type vs. knock-out rats uncovered evidence that capsaicin may function in an antinociceptive capacity independent of TRPV1 signaling. Our data suggest that neuroimaging of pain in awake, conscious animals has the potential to inform the neurobiological basis of full and integrated perceptions of pain.
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Affiliation(s)
- Jason R Yee
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - William Kenkel
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - John C Caccaviello
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | | | | | | | - Praveen Kulkarni
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - Craig F Ferris
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
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Hubbard CS, Khan SA, Xu S, Cha M, Masri R, Seminowicz DA. Behavioral, metabolic and functional brain changes in a rat model of chronic neuropathic pain: a longitudinal MRI study. Neuroimage 2014; 107:333-344. [PMID: 25524649 DOI: 10.1016/j.neuroimage.2014.12.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/31/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023] Open
Abstract
Peripheral neuropathy often manifests clinically with symptoms of mechanical and cold allodynia. However, the neuroplastic changes associated with peripheral neuropathic pain and the onset and progression of allodynic symptoms remain unclear. Here, we used a chronic neuropathic pain model (spared nerve injury; SNI) to examine functional and metabolic brain changes associated with the development and maintenance of mechanical and cold hypersensitivity, the latter which we assessed both behaviorally and during a novel acetone application paradigm using functional MRI (fMRI). Female Sprague-Dawley rats underwent SNI (n=7) or sham (n=5) surgery to the left hindpaw. Rats were anesthetized and scanned using a 7 T MRI scanner 1 week prior to (pre-injury) and 4 (early/subchronic) and 20 weeks (late/chronic) post-injury. Functional scans were acquired during acetone application to the left hindpaw. (1)H magnetic resonance spectroscopy was also performed to assess SNI-induced metabolic changes in the anterior cingulate cortex (ACC) pre- and 4 weeks post-injury. Mechanical and cold sensitivity, as well as anxiety-like behaviors, were assessed 2 weeks pre-injury, and 2, 5, 9, 14, and 19 weeks post-injury. Stimulus-evoked brain responses (acetone application to the left hindpaw) were analyzed across the pre- and post-injury time points. In response to acetone application during fMRI, SNI rats showed widespread and functionally diverse changes within pain-related brain regions including somatosensory and cingulate cortices and subcortically within the thalamus and the periaqueductal gray. These functional brain changes temporally coincided with early and sustained increases in both mechanical and cold sensitivity. SNI rats also showed increased glutamate within the ACC that correlated with behavioral measures of cold hypersensitivity. Together, our findings suggest that extensive functional reorganization within pain-related brain regions may underlie the development and chronification of allodynic-like behaviors.
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Affiliation(s)
- Catherine S Hubbard
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA
| | - Shariq A Khan
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Myeounghoon Cha
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, USA
| | - Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David A Seminowicz
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Balla DZ, Schwarz S, Wiesner HM, Hennige AM, Pohmann R. Monitoring the stress-level of rats with different types of anesthesia: a tail-artery cannulation protocol. J Pharmacol Toxicol Methods 2014; 70:35-9. [PMID: 24632523 DOI: 10.1016/j.vascn.2014.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 02/04/2014] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Functional MRI in rats under anesthesia can largely minimize motion artifacts and attenuate the stress of the animal. However, two issues remain to be clarified and improved. First, fMRI results obtained with different types of anesthesia during surgical preparation and imaging show a large variability, which could be caused by the variable stress level of the rodents. Second, the most common surgical procedure used for anesthesia, blood gas analysis and mean arterial blood-pressure (MABP) monitoring is the femoral vein and artery catheterization that makes longitudinal studies difficult. METHODS In order to examine the variability of the stress level with three different anesthesia protocols using isoflurane (Iso), medetomidine-ketamine (MK) or propofol-remifentanil (PR), we measured the plasma corticosterone (CORT) concentration with (125)I-radioimmunoassay in blood samples collected prior to, immediately after and 60min after surgery. Tail-artery and vein catheterization was adapted for long-term monitoring of MABP with periodic blood sampling and is proposed as a less invasive and technically simple alternative to femoral vessel catheterization in fMRI preparation protocols. RESULTS We show that the CORT concentration depends on the anesthesia protocol with both alternatives providing more efficient stress reduction than the protocol using Iso. However, only the protocol using PR achieved a significant hormone reduction during surgery. Stress was not reliably manifested in changes in heart-rate and breathing-rate. Anesthesia and strain related changes in these two physiological parameters may be assigned to the pharmacological effects of the premedication and anesthetic agents. The results indicate also that MABP can be monitored over a long period of time (e.g. functional imaging session) through an arterial access point in the rat tail after cannulation with the proposed procedure. DISCUSSION AND CONCLUSION Animals can experience stress during fMRI preparation protocols without obvious signs in commonly monitored physiological parameters. Our results challenge the efficiency of surgical protocols using Iso as mono-anesthetic agent, even when extended with topical analgesia. It was demonstrated that the CORT-based stress-level measurement through tail-artery cannulation can be used for developing anesthesia protocols (i.e. the presented PR protocol) when setting up future fMRI studies. The proposed surgical method for the tail is expected to facilitate longitudinal fMRI studies with permanent arterial access.
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Affiliation(s)
- Dávid Z Balla
- High-Field MR Center, Max-Planck-Institute for Biological Cybernetics, Spemannstr. 41, 72076 Tübingen, Germany.
| | - Saskia Schwarz
- High-Field MR Center, Max-Planck-Institute for Biological Cybernetics, Spemannstr. 41, 72076 Tübingen, Germany
| | - Hannes M Wiesner
- High-Field MR Center, Max-Planck-Institute for Biological Cybernetics, Spemannstr. 41, 72076 Tübingen, Germany
| | - Anita M Hennige
- Department of Internal Medicine, Eberhard Karls University, Otfried-Müller-Str. 10, 72076 Tübingen, Germany
| | - Rolf Pohmann
- High-Field MR Center, Max-Planck-Institute for Biological Cybernetics, Spemannstr. 41, 72076 Tübingen, Germany
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Abstract
Abstract:As Colin Allen has argued, discussions between science and ethics about the mentality and moral status of nonhuman animals often stall on account of the fact that the properties that ethics presents as evidence of animal mentality and moral status, namely consciousness and sentience, are not observable “scientifically respectable” properties. In order to further discussion between science and ethics, it seems, therefore, that we need to identify properties that would satisfy both domains.In this article I examine the mentality and moral status of nonhuman animals from the perspective of neuroethics. By adopting this perspective, we can see how advances in neuroimaging regarding (1) research into the neurobiology of pain, (2) “brain reading,” and (3) the minimally conscious state may enable us to identify properties that help bridge the gap between science and ethics, and hence help further the debate about the mentality and moral status of nonhuman animals.
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Thompson SJ, Millecamps M, Aliaga A, Seminowicz DA, Low LA, Bedell BJ, Stone LS, Schweinhardt P, Bushnell MC. Metabolic brain activity suggestive of persistent pain in a rat model of neuropathic pain. Neuroimage 2014; 91:344-52. [PMID: 24462776 DOI: 10.1016/j.neuroimage.2014.01.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/07/2013] [Accepted: 01/13/2014] [Indexed: 10/25/2022] Open
Abstract
Persistent pain is a central characteristic of neuropathic pain conditions in humans. Knowing whether rodent models of neuropathic pain produce persistent pain is therefore crucial to their translational applicability. We investigated the spared nerve injury (SNI) model of neuropathic pain and the formalin pain model in rats using positron emission tomography (PET) with the metabolic tracer [18F]fluorodeoxyglucose (FDG) to determine if there is ongoing brain activity suggestive of persistent pain. For the formalin model, under brief anesthesia we injected one hindpaw with 5% formalin and the FDG tracer into a tail vein. We then allowed the animals to awaken and observed pain behavior for 30min during the FDG uptake period. The rat was then anesthetized and placed in the scanner for static image acquisition, which took place between minutes 45 and 75 post-tracer injection. A single reference rat brain magnetic resonance image (MRI) was used to align the PET images with the Paxinos and Watson rat brain atlas. Increased glucose metabolism was observed in the somatosensory region associated with the injection site (S1 hindlimb contralateral), S1 jaw/upper lip and cingulate cortex. Decreases were observed in the prelimbic cortex and hippocampus. Second, SNI rats were scanned 3weeks post-surgery using the same scanning paradigm, and region-of-interest analyses revealed increased metabolic activity in the contralateral S1 hindlimb. Finally, a second cohort of SNI rats was scanned while anesthetized during the tracer uptake period, and the S1 hindlimb increase was not observed. Increased brain activity in the somatosensory cortex of SNI rats resembled the activity produced with the injection of formalin, suggesting that the SNI model may produce persistent pain. The lack of increased activity in S1 hindlimb with general anesthetic demonstrates that this effect can be blocked, as well as highlights the importance of investigating brain activity in awake and behaving rodents.
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Affiliation(s)
- Scott J Thompson
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC H3G 0G1, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2T5, Canada.
| | - Magali Millecamps
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC H3G 0G1, Canada; Faculty of Dentistry, McGill University, Montreal, QC H3A 2T5, Canada
| | - Antonio Aliaga
- Small Animal Imaging Lab, McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - David A Seminowicz
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Lucie A Low
- Division of Intramural Research, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barry J Bedell
- Small Animal Imaging Lab, McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada; Department of Neurology & Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - Laura S Stone
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC H3G 0G1, Canada; Faculty of Dentistry, McGill University, Montreal, QC H3A 2T5, Canada; Department of Neurology & Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - Petra Schweinhardt
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC H3G 0G1, Canada; Faculty of Dentistry, McGill University, Montreal, QC H3A 2T5, Canada; Department of Neurology & Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - M Catherine Bushnell
- Division of Intramural Research, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892, USA
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Jiang L, Ji Y, Voulalas PJ, Keaser M, Xu S, Gullapalli RP, Greenspan J, Masri R. Motor cortex stimulation suppresses cortical responses to noxious hindpaw stimulation after spinal cord lesion in rats. Brain Stimul 2013; 7:182-9. [PMID: 24468093 DOI: 10.1016/j.brs.2013.12.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Motor cortex stimulation (MCS) is a potentially effective treatment for chronic neuropathic pain. The neural mechanisms underlying the reduction of hyperalgesia and allodynia after MCS are not completely understood. OBJECTIVE To investigate the neural mechanisms responsible for analgesic effects after MCS. We test the hypothesis that MCS attenuates evoked blood oxygen-level dependent signals in cortical areas involved in nociceptive processing in an animal model of chronic neuropathic pain. METHODS We used adult female Sprague-Dawley rats (n = 10) that received unilateral electrolytic lesions of the right spinal cord at the level of C6 (SCL animals). In these animals, we performed magnetic resonance imaging (fMRI) experiments to study the analgesic effects of MCS. On the day of fMRI experiment, 14 days after spinal cord lesion, the animals were anesthetized and epidural bipolar platinum electrodes were placed above the left primary motor cortex. Two 10-min sessions of fMRI were performed before and after a session of MCS (50 μA, 50 Hz, 300 μs, for 30 min). During each fMRI session, the right hindpaw was electrically stimulated (noxious stimulation: 5 mA, 5 Hz, 3 ms) using a block design of 20 s stimulation off and 20 s stimulation on. A general linear model-based statistical parametric analysis was used to analyze whole brain activation maps. Region of interest (ROI) analysis and paired t-test were used to compare changes in activation before and after MCS in these ROI. RESULTS MCS suppressed evoked blood oxygen dependent signals significantly (Family-wise error corrected P < 0.05) and bilaterally in 2 areas heavily implicated in nociceptive processing. These areas consisted of the primary somatosensory cortex and the prefrontal cortex. CONCLUSIONS These findings suggest that, in animals with SCL, MCS attenuates hypersensitivity by suppressing activity in the primary somatosensory cortex and prefrontal cortex.
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Affiliation(s)
- Li Jiang
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yadong Ji
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Pamela J Voulalas
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael Keaser
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Su Xu
- Department of Sciences of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging at Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rao P Gullapalli
- Department of Sciences of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Core for Translational Research in Imaging at Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joel Greenspan
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Radi Masri
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Linnman C, Borsook D. Completing the Pain Circuit: Recent Advances in Imaging Pain and Inflammation beyond the Central Nervous System. Rambam Maimonides Med J 2013; 4:e0026. [PMID: 24228169 PMCID: PMC3820299 DOI: 10.5041/rmmj.10133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
This review describes some of the recent developments in imaging aspects of pain in the periphery. It is now possible to image nerves in the cornea non-invasively, to image receptor level expression and inflammatory processes in injured tissue, to image nerves and alterations in nerve properties, to image astrocyte and glial roles in neuroinflammatory processes, and to image pain conduction functionally in the trigeminal ganglion. These advances will ultimately allow us to describe the pain pathway, from injury site to behavioral consequence, in a quantitative manner. Such a development could lead to diagnostics determining the source of pain (peripheral or central), objective monitoring of treatment progression, and, hopefully, objective biomarkers of pain.
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Affiliation(s)
- Clas Linnman
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts, United States of America
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Jonckers E, Van der Linden A, Verhoye M. Functional magnetic resonance imaging in rodents: an unique tool to study in vivo pharmacologic neuromodulation. Curr Opin Pharmacol 2013; 13:813-20. [PMID: 23856429 DOI: 10.1016/j.coph.2013.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 06/25/2013] [Accepted: 06/25/2013] [Indexed: 10/26/2022]
Abstract
When new compounds targeting the brain are developed, it is important to assess both the acute and chronic effects on brain functioning. This can be done non-invasively using a technique called functional magnetic resonance imaging (fMRI). This review discusses the possibilities of both stimulation-based and resting state fMRI to study pharmacological modulations of the rodent brain. Moreover, attention is given to the use of anesthetics which could importantly influence the outcome of both techniques.
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Yen CT, Lu PL. Thalamus and pain. ACTA ACUST UNITED AC 2013; 51:73-80. [DOI: 10.1016/j.aat.2013.06.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 05/13/2013] [Indexed: 02/02/2023]
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Abstract
Nerve damage takes place during surgery. As a consequence, significant numbers (10%-40%) of patients experience chronic neuropathic pain termed surgically induced neuropathic pain (SNPP). The initiating surgery and nerve damage set off a cascade of events that includes both pain and an inflammatory response, resulting in "peripheral and central sensitization," with the latter resulting from repeated barrages of neural activity from nociceptors. In affected patients, these initial events produce chemical, structural, and functional changes in the peripheral and central nervous systems (CNS). The maladaptive changes in damaged nerves lead to peripheral manifestations of the neuropathic state-allodynia, sensory loss, shooting pains, etc, that can manifest long after the effects of the surgical injury have resolved. The CNS manifestations that occur are termed "centralization of pain" and affect sensory, emotional, and other (eg, cognitive) systems as well as contributing to some of the manifestations of the chronic pain syndrome (eg, depression). Currently there are no objective measures of nociception and pain in the perioperative period. As such, intermittent or continuous pain may take place during and after surgery. New technologies including direct measures of specific brain function of nociception and new insights into preoperative evaluation of patients including genetic predisposition, appear to provide initial opportunities for decreasing the burden of SNPP, until treatments with high efficacy and low adverse effects that either prevent or treat pain are discovered.
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Abstract
PURPOSE OF REVIEW This review summarizes key findings of the current literature on functional neuroimaging in migraine and describes how these studies have changed our view of the disorder. RECENT FINDINGS Recent studies have started not only to investigate the global cerebral activation pattern during migraine attacks, but to address specific aspects of migraine attacks such as photophobia, osmophobia as well as pain perception with the aim of disentangling the underlying mechanisms. There is also more and more evidence that the migraine brain is abnormal even outside of attacks and that repeated attacks are leading to functional and structural alterations in the brain, which may in turn drive the transformation of migraine to its chronic form. Some new results are pinpointing toward a potential role of interesting new brain areas in migraine pathophysiology such as the temporal cortex or the basal ganglia. SUMMARY Neuroimaging studies are beginning to shed light on the mechanisms underlying the development and evolution of migraine and its specific symptoms. Future studies have the potential to also improve our understanding of established and upcoming treatment approaches and to monitor treatment effects in an objective and noninvasive way.
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Kwilasz AJ, Negus SS. Dissociable effects of the cannabinoid receptor agonists Δ9-tetrahydrocannabinol and CP55940 on pain-stimulated versus pain-depressed behavior in rats. J Pharmacol Exp Ther 2012; 343:389-400. [PMID: 22892341 DOI: 10.1124/jpet.112.197780] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cannabinoid receptor agonists produce reliable antinociception in most preclinical pain assays but have inconsistent analgesic efficacy in humans. This disparity suggests that conventional preclinical assays of nociception are not sufficient for the prediction of cannabinoid effects related to clinical analgesia. To extend the range of preclinical cannabinoid assessment, this study compared the effects of the marijuana constituent and low-efficacy cannabinoid agonist Δ9-tetrahydrocannabinol (THC) and the high-efficacy synthetic cannabinoid agonist 3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol (CP55940) in assays of pain-stimulated and pain-depressed behavior. Intraperitoneal injection of dilute lactic acid (1.8% in 1 ml/kg) stimulated a stretching response or depressed intracranial self-stimulation (ICSS) in separate groups of male Sprague-Dawley rats. THC (0.1-10 mg/kg) and CP55940 (0.0032-0.32 mg/kg) dose-dependently blocked acid- stimulated stretching but only exacerbated acid-induced depression of ICSS at doses that also decreased control ICSS in the absence of a noxious stimulus. Repeated THC produced tolerance to sedative rate-decreasing effects of THC on control ICSS in the absence of the noxious stimulus but failed to unmask antinociception in the presence of the noxious stimulus. THC and CP55940 also failed to block pain-related depression of feeding in rats, although THC did attenuate satiation-related depression of feeding. In contrast to the effects of the cannabinoid agonists, the clinically effective analgesic and nonsteroidal anti-inflammatory drug ketoprofen (1 mg/kg) blocked acid-stimulated stretching and acid-induced depression of both ICSS and feeding. The poor efficacy of THC and CP55940 to block acute pain-related depression of behavior in rats agrees with the poor efficacy of cannabinoids to treat acute pain in humans.
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Affiliation(s)
- Andrew J Kwilasz
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, PO Box 980613, Richmond, VA 23298, USA
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Abstract
The discovery of cortical networks that participate in pain processing has led to the common generalization that blood oxygen level-dependent (BOLD) responses in these areas indicate the processing of pain. Physical stimuli have fundamental properties that elicit sensations distinguishable from pain, such as heat. We hypothesized that pain intensity coding may reflect the intensity coding of heat sensation during the presentation of thermal stimuli during fMRI. Six 3T fMRI heat scans were collected for 16 healthy subjects, corresponding to perceptual levels of "low innocuous heat," "moderate innocuous heat," "high innocuous heat," "low painful heat," "moderate painful heat," and "high painful heat" delivered by a contact thermode to the face. Subjects rated pain and heat intensity separately after each scan. A general linear model analysis detected different patterns of brain activation for the different phases of the biphasic response to heat. During high painful heat, the early phase was associated with significant anterior insula and anterior cingulate cortex activation. Persistent responses were detected in the right dorsolateral prefrontal cortex and inferior parietal lobule. Only the late phase showed significant correlations with perceptual ratings. Significant heat intensity correlated activation was identified in contralateral primary and secondary somatosensory cortices, motor cortex, and superior temporal lobe. These areas were significantly more related to heat ratings than pain. These results indicate that heat intensity is encoded by the somatosensory cortices, and that pain evaluation may either arise from multimodal evaluative processes, or is a distributed process.
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Shelton L, Becerra L, Borsook D. Unmasking the mysteries of the habenula in pain and analgesia. Prog Neurobiol 2012; 96:208-19. [PMID: 22270045 PMCID: PMC3465722 DOI: 10.1016/j.pneurobio.2012.01.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 11/01/2011] [Accepted: 01/06/2012] [Indexed: 02/06/2023]
Abstract
The habenula is a small bilateral structure in the posterior-medial aspect of the dorsal thalamus that has been implicated in a remarkably wide range of behaviors including olfaction, ingestion, mating, endocrine and reward function, pain and analgesia. Afferent connections from forebrain structures send inputs to the lateral and medial habenula where efferents are mainly projected to brainstem regions that include well-known pain modulatory regions such as the periaqueductal gray and raphe nuclei. A convergence of preclinical data implicates the region in multiple behaviors that may be considered part of the pain experience including a putative role in pain modulation, affective, and motivational processes. The habenula seems to play a role as an evaluator, acting as a major point of convergence where external stimuli is received, evaluated, and redirected for motivation of appropriate behavioral response. Here, we review the role of the habenula in pain and analgesia, consider its potential role in chronic pain, and review more recent clinical and functional imaging data of the habenula from animals and humans. Even through the habenula is a small brain structure, advances in structural and functional imaging in humans should allow for further advancement of our understanding of its role in pain and analgesia.
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Affiliation(s)
- L. Shelton
- Center for Pain and the Brain, Harvard Medical School, United States
- Children’s Hospital Boston, Harvard Medical School, United States
| | - L. Becerra
- Center for Pain and the Brain, Harvard Medical School, United States
- Children’s Hospital Boston, Harvard Medical School, United States
- McLean Hospital, Harvard Medical School, United States
- Massachusetts General Hospital, Harvard Medical School, United States
| | - D. Borsook
- Center for Pain and the Brain, Harvard Medical School, United States
- Children’s Hospital Boston, Harvard Medical School, United States
- McLean Hospital, Harvard Medical School, United States
- Massachusetts General Hospital, Harvard Medical School, United States
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48
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Experimental protocols for behavioral imaging: seeing animal models of drug abuse in a new light. Curr Top Behav Neurosci 2012; 11:93-115. [PMID: 22411423 DOI: 10.1007/7854_2012_206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Behavioral neuroimaging is a rapidly evolving discipline that represents a marriage between the fields of behavioral neuroscience and preclinical molecular imaging. This union highlights the changing role of imaging in translational research. Techniques developed for humans are now widely applied in the study of animal models of brain disorders such as drug addiction. Small animal or preclinical imaging allows us to interrogate core features of addiction from both behavioral and biological endpoints. Snapshots of brain activity allow us to better understand changes in brain function and behavior associated with initial drug exposure, the emergence of drug escalation, and repeated bouts of drug withdrawal and relapse. Here we review the development and validation of new behavioral imaging paradigms and several clinically relevant radiotracers used to capture dynamic molecular events in behaving animals. We will discuss ways in which behavioral imaging protocols can be optimized to increase throughput and quantitative methods. Finally, we discuss our experience with the practical aspects of behavioral neuroimaging, so investigators can utilize effective animal models to better understand the addicted brain and behavior.
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Borsook D, Hargreaves R, Becerra L. Can Functional Magnetic Resonance Imaging Improve Success Rates in CNS Drug Discovery? Expert Opin Drug Discov 2011; 6:597-617. [PMID: 21765857 DOI: 10.1517/17460441.2011.584529] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION: The bar for developing new treatments for CNS disease is getting progressively higher and fewer novel mechanisms are being discovered, validated and developed. The high costs of drug discovery necessitate early decisions to ensure the best molecules and hypotheses are tested in expensive late stage clinical trials. The discovery of brain imaging biomarkers that can bridge preclinical to clinical CNS drug discovery and provide a 'language of translation' affords the opportunity to improve the objectivity of decision-making. AREAS COVERED: This review discusses the benefits, challenges and potential issues of using a science based biomarker strategy to change the paradigm of CNS drug development and increase success rates in the discovery of new medicines. The authors have summarized PubMed and Google Scholar based publication searches to identify recent advances in functional, structural and chemical brain imaging and have discussed how these techniques may be useful in defining CNS disease state and drug effects during drug development. EXPERT OPINION: The use of novel brain imaging biomarkers holds the bold promise of making neuroscience drug discovery smarter by increasing the objectivity of decision making thereby improving the probability of success of identifying useful drugs to treat CNS diseases. Functional imaging holds the promise to: (1) define pharmacodynamic markers as an index of target engagement (2) improve translational medicine paradigms to predict efficacy; (3) evaluate CNS efficacy and safety based on brain activation; (4) determine brain activity drug dose-response relationships and (5) provide an objective evaluation of symptom response and disease modification.
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Affiliation(s)
- David Borsook
- Center for Pain and the Brain, MGH, McLean and Children's Hospitals, Harvard Medical School And Merck Research Laboratories
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Hache G, Coudore F, Gardier AM, Guiard BP. Monoaminergic Antidepressants in the Relief of Pain: Potential Therapeutic Utility of Triple Reuptake Inhibitors (TRIs). Pharmaceuticals (Basel) 2011. [PMCID: PMC4053958 DOI: 10.3390/ph4020285] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Over 75% of depressed patients suffer from painful symptoms predicting a greater severity and a less favorable outcome of depression. Imaging, anatomical and functional studies have demonstrated the existence of common brain structures, neuronal pathways and neurotransmitters in depression and pain. In particular, the ascending serotonergic and noradrenergic pathways originating from the raphe nuclei and the locus coeruleus; respectively, send projections to the limbic system. Such pathways control many of the psychological functions that are disturbed in depression and in the perception of pain. On the other hand, the descending pathways, from monoaminergic nuclei to the spinal cord, are specifically implicated in the inhibition of nociception providing rationale for the use of serotonin (5-HT) and/or norepinephrine (NE) reuptake inhibitors (SSRIs, NRIs, SNRIs), in the relief of pain. Compelling evidence suggests that dopamine (DA) is also involved in the pathophysiology and treatment of depression. Indeed, recent insights have demonstrated a central role for DA in analgesia through an action at both the spinal and suprasinal levels including brain regions such as the periaqueductal grey (PAG), the thalamus, the basal ganglia and the limbic system. In this context, dopaminergic antidepressants (i.e., containing dopaminergic activity), such as bupropion, nomifensine and more recently triple reuptake inhibitors (TRIs), might represent new promising therapeutic tools in the treatment of painful symptoms with depression. Nevertheless, whether the addition of the dopaminergic component produces more robust effects than single- or dual-acting agents, has yet to be demonstrated. This article reviews the main pathways regulating pain transmission in relation with the monoaminergic systems. It then focuses on the current knowledge regarding the in vivo pharmacological properties and mechanism of action of monoaminergic antidepressants including SSRIs, NRIs, SNRIs and TRIs. Finally, a synthesis of the preclinical studies supporting the efficacy of these antidepressants in analgesia is also addressed in order to highlight the relative contribution of 5-HT, NE and DA to nociception.
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Affiliation(s)
- Guillaume Hache
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: 011-331-46-83-53-61
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