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Reis FMCV, Mobbs D, Canteras NS, Adhikari A. Orchestration of innate and conditioned defensive actions by the periaqueductal gray. Neuropharmacology 2023; 228:109458. [PMID: 36773777 DOI: 10.1016/j.neuropharm.2023.109458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023]
Abstract
The midbrain periaqueductal gray (PAG) has been recognized for decades as having a central role in the control of a wide variety of defensive responses. Initial discoveries relied primarily on lesions, electrical stimulation and pharmacology. Recent developments in neural activity imaging and in methods to control activity with anatomical and genetic specificity have revealed additional streams of data informing our understanding of PAG function. Here, we discuss both classic and modern studies reporting on how PAG-centered circuits influence innate as well as learned defensive actions in rodents and humans. Though early discoveries emphasized the PAG's role in rapid induction of innate defensive actions, emerging new data indicate a prominent role for the PAG in more complex processes, including representing behavioral states and influencing fear learning and memory. This article is part of the Special Issue on "Fear, Anxiety and PTSD".
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Affiliation(s)
- Fernando M C V Reis
- Department of Psychology, University of California, Los Angeles, CA, United States.
| | - Dean Mobbs
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, United States; Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA, United States
| | - Newton S Canteras
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Avishek Adhikari
- Department of Psychology, University of California, Los Angeles, CA, United States.
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2
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Zhang Y, Furst AJ. Brainstem Diffusion Tensor Tractography and Clinical Applications in Pain. FRONTIERS IN PAIN RESEARCH (LAUSANNE, SWITZERLAND) 2022; 3:840328. [PMID: 35399154 PMCID: PMC8989264 DOI: 10.3389/fpain.2022.840328] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022]
Abstract
The brainstem is one of the most vulnerable brain structures in many neurological conditions, such as pain, sleep problems, autonomic dysfunctions, and neurodegenerative disorders. Diffusion tensor imaging and tractography provide structural details and quantitative measures of brainstem fiber pathways. Until recently, diffusion tensor tractographic studies have mainly focused on whole-brain MRI acquisition. Due to the brainstem's spatial localization, size, and tissue characteristics, and limits of imaging techniques, brainstem diffusion MRI poses particular challenges in tractography. We provide a brief overview on recent advances in diffusion tensor tractography in revealing human pathways connecting the brainstem to the subcortical regions (e.g., basal ganglia, mesolimbic, basal forebrain), and cortical regions. Each of these pathways contains different distributions of fiber tracts from known neurotransmitter-specific nuclei in the brainstem. We compare the brainstem tractographic approaches in literature and our in-lab developed automated brainstem tractography in terms of atlas building, technical advantages, and neuroanatomical implications on neurotransmitter systems. Lastly, we summarize recent investigations of using brainstem tractography as a promising tool in association with pain.
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Affiliation(s)
- Yu Zhang
- War Related Illness and Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States,*Correspondence: Yu Zhang ;
| | - Ansgar J. Furst
- War Related Illness and Injury Study Center (WRIISC), VA Palo Alto Health Care System, Palo Alto, CA, United States,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, United States,Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, CA, United States,Polytrauma System of Care (PSC), VA Palo Alto Health Care System, Palo Alto, CA, United States
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3
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Browne JD, Fraiser R, Cai Y, Leung D, Leung A, Vaninetti M. Unveiling the phantom: What neuroimaging has taught us about phantom limb pain. Brain Behav 2022; 12:e2509. [PMID: 35218308 PMCID: PMC8933774 DOI: 10.1002/brb3.2509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/05/2021] [Accepted: 01/11/2022] [Indexed: 11/08/2022] Open
Abstract
Phantom limb pain (PLP) is a complicated condition with diverse clinical challenges. It consists of pain perception of a previously amputated limb. The exact pain mechanism is disputed and includes mechanisms involving cerebral, peripheral, and spinal origins. Such controversy limits researchers' and clinicians' ability to develop consistent therapeutics or management. Neuroimaging is an essential tool that can address this problem. This review explores diffusion tensor imaging, functional magnetic resonance imaging, electroencephalography, and magnetoencephalography in the context of PLP. These imaging modalities have distinct mechanisms, implications, applications, and limitations. Diffusion tensor imaging can outline structural changes and has surgical applications. Functional magnetic resonance imaging captures functional changes with spatial resolution and has therapeutic applications. Electroencephalography and magnetoencephalography can identify functional changes with a strong temporal resolution. Each imaging technique provides a unique perspective and they can be used in concert to reveal the true nature of PLP. Furthermore, researchers can utilize the respective strengths of each neuroimaging technique to support the development of innovative therapies. PLP exemplifies how neuroimaging and clinical management are intricately connected. This review can assist clinicians and researchers seeking a foundation for applications and understanding the limitations of neuroimaging techniques in the context of PLP.
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Affiliation(s)
- Jonathan D Browne
- School of Medicine, California University of Science and Medicine, Colton, California, USA
| | - Ryan Fraiser
- Center for Pain Medicine, University of California San Diego, La Jolla, California, USA
| | - Yi Cai
- Center for Pain Medicine, University of California San Diego, La Jolla, California, USA
| | - Dillon Leung
- College of Letters and Science, University of California Berkeley, Berkeley, California, USA
| | - Albert Leung
- Center for Pain Medicine, University of California San Diego, La Jolla, California, USA
| | - Michael Vaninetti
- Center for Pain Medicine, University of California San Diego, La Jolla, California, USA
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4
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Paulo DL, Bick SK. Advanced Imaging in Psychiatric Neurosurgery: Toward Personalized Treatment. Neuromodulation 2021; 25:195-201. [PMID: 33788971 DOI: 10.1111/ner.13392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/22/2021] [Accepted: 03/08/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Our aim is to review several recent landmark studies discussing the application of advanced neuroimaging to guide target selection in deep brain stimulation (DBS) for psychiatric disorders. MATERIALS AND METHODS We performed a PubMed literature search of articles related to psychiatric neurosurgery, DBS, diffusion tensor imaging, probabilistic tractography, functional magnetic resonance imaging (MRI), and blood oxygen level-dependent activation. Relevant articles were included in the review. RESULTS Recent advances in neuroimaging, namely the use of diffusion tensor imaging, probabilistic tractography, functional MRI, and Positron emission tomography have provided higher resolution depictions of structural and functional connectivity between regions of interest. Applying these imaging modalities to DBS has increased understanding of the mechanism of action of DBS from the single structure to network level, allowed for new DBS targets to be discovered, and allowed for individualized DBS targeting for psychiatric indications. CONCLUSIONS Advanced neuroimaging techniques may be especially important to guide personalized DBS targeting in psychiatric disorders such as treatment-resistant depression and obsessive-compulsive disorder where symptom profiles and underlying disordered circuitry are more heterogeneous. These articles suggest that advanced imaging can help to further individualize and optimize DBS, a promising next step in improving its efficacy.
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Affiliation(s)
- Danika L Paulo
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sarah K Bick
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
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Cacciola A, Bertino S, Basile GA, Di Mauro D, Calamuneri A, Chillemi G, Duca A, Bruschetta D, Flace P, Favaloro A, Calabrò RS, Anastasi G, Milardi D. Mapping the structural connectivity between the periaqueductal gray and the cerebellum in humans. Brain Struct Funct 2019; 224:2153-2165. [PMID: 31165919 PMCID: PMC6591182 DOI: 10.1007/s00429-019-01893-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 05/21/2019] [Indexed: 02/06/2023]
Abstract
The periaqueductal gray is a mesencephalic structure involved in modulation of responses to stressful stimuli. Structural connections between the periaqueductal gray and the cerebellum have been described in animals and in a few diffusion tensor imaging studies. Nevertheless, these periaqueductal gray–cerebellum connectivity patterns have yet to be fully investigated in humans. The objective of this study was to qualitatively and quantitatively characterize such pathways using high-resolution, multi-shell data of 100 healthy subjects from the open-access Human Connectome Project repository combined with constrained spherical deconvolution probabilistic tractography. Our analysis revealed robust connectivity density profiles between the periaqueductal gray and cerebellar nuclei, especially with the fastigial nucleus, followed by the interposed and dentate nuclei. High-connectivity densities have been observed between vermal (Vermis IX, Vermis VIIIa, Vermis VIIIb, Vermis VI, Vermis X) and hemispheric cerebellar regions (Lobule IX). Our in vivo study provides for the first time insights on the organization of periaqueductal gray–cerebellar pathways thus opening new perspectives on cognitive, visceral and motor responses to threatening stimuli in humans.
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Affiliation(s)
- Alberto Cacciola
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy.
| | - Salvatore Bertino
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Gianpaolo Antonio Basile
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Debora Di Mauro
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | | | | | - Antonio Duca
- IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy
| | - Daniele Bruschetta
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Paolo Flace
- School of Medicine, University of Bari 'Aldo Moro', Bari, Italy
| | - Angelo Favaloro
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
- School of Medicine, University of Bari 'Aldo Moro', Bari, Italy
| | | | - Giuseppe Anastasi
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Demetrio Milardi
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
- IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy
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De Vloo P, Nuttin B. Stereotaxy in rat models: Current state of the art, proposals to improve targeting accuracy and reporting guideline. Behav Brain Res 2019; 364:457-463. [DOI: 10.1016/j.bbr.2017.10.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022]
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See AAQ, King NKK. Improving Surgical Outcome Using Diffusion Tensor Imaging Techniques in Deep Brain Stimulation. Front Surg 2017; 4:54. [PMID: 29034243 PMCID: PMC5625016 DOI: 10.3389/fsurg.2017.00054] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 09/06/2017] [Indexed: 12/16/2022] Open
Abstract
Introduction Recent advances in surgical imaging include the use of diffusion tensor imaging (DTI) in deep brain stimulation (DBS) and provide a detailed view of the white matter tracts and their connections which are not seen with conventional magnetic resonance imaging. Given that the efficacy of DBS depends on the precise and accurate targeting of these circuits, better surgical planning using information obtained from DTI may lead to improved surgical outcome. We aim to review the available literature to evaluate the efficacy of such a strategy. Methods A search of PubMed was performed to identify all articles using the search terms “(diffusion tractography OR diffusion tensor imaging OR DTI) AND (deep brain stimulation OR DBS).” Studies were included if DTI was used and clinical outcomes were reported. Results We identified 35 studies where the use of DTI in DBS was evaluated. The most studied pathology was movement disorders (17 studies), psychiatric disorders (11 studies), and pain (7 studies). The overall responder rates for tremor reduction was 70.0% (SD = 26.1%) in 69 patients, 36.5% (SD = 19.1%) for obsessive–compulsive disorder in 9 patients, 48.3% (SD = 40.0%) for depression in 40 patients, and 49.7% (SD = 35.1%) for chronic pain in 23 patients. Discussion The studies reviewed show that the use of DTI for surgical planning is feasible, provide additional information over conventional targeting methods, and can improve surgical outcome. Patients in whom the DBS electrodes were within the DTI targets experienced better outcomes than those in whom the electrodes were not. Many current studies are limited by their small sample size or retrospective nature. The use of DTI in DBS planning appears underutilized and further studies are warranted given that surgical outcome can be optimized using this non-invasive technique.
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Affiliation(s)
- Angela An Qi See
- Department of Neurosurgery, National Neuroscience Institute, Singapore, Singapore
| | - Nicolas Kon Kam King
- Department of Neurosurgery, National Neuroscience Institute, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
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Menant O, Andersson F, Zelena D, Chaillou E. The benefits of magnetic resonance imaging methods to extend the knowledge of the anatomical organisation of the periaqueductal gray in mammals. J Chem Neuroanat 2016; 77:110-120. [DOI: 10.1016/j.jchemneu.2016.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 10/21/2022]
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Calabrese E. Diffusion Tractography in Deep Brain Stimulation Surgery: A Review. Front Neuroanat 2016; 10:45. [PMID: 27199677 PMCID: PMC4852260 DOI: 10.3389/fnana.2016.00045] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/08/2016] [Indexed: 12/27/2022] Open
Abstract
Deep brain stimulation (DBS) is believed to exert its therapeutic effects through modulation of brain circuitry, yet conventional preoperative planning does not allow direct targeting or visualization of white matter pathways. Diffusion MRI tractography (DT) is virtually the only non-invasive method of visualizing structural connectivity in the brain, leading many to suggest its use to guide DBS targeting. DT-guided DBS not only has the potential to allow direct white matter targeting for established applications [e.g., Parkinson’s disease (PD), essential tremor (ET), dystonia], but may also aid in the discovery of new therapeutic targets for a variety of other neurologic and psychiatric diseases. Despite these exciting opportunities, DT lacks standardization and rigorous anatomic validation, raising significant concern for the use of such data in stereotactic brain surgery. This review covers the technical details, proposed methods, and initial clinical data for the use of DT in DBS surgery. Rather than focusing on specific disease applications, this review focuses on methods that can be applied to virtually any DBS target.
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Affiliation(s)
- Evan Calabrese
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center Durham, NC, USA
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10
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Ezra M, Faull OK, Jbabdi S, Pattinson KT. Connectivity-based segmentation of the periaqueductal gray matter in human with brainstem optimized diffusion MRI. Hum Brain Mapp 2015; 36:3459-71. [PMID: 26138504 PMCID: PMC4755135 DOI: 10.1002/hbm.22855] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/12/2015] [Accepted: 05/15/2015] [Indexed: 12/02/2022] Open
Abstract
The periaqueductal gray matter (PAG) is a midbrain structure, involved in key homeostatic neurobiological functions, such as pain modulation and cardiorespiratory control. Animal research has identified four subdivisional columns that differ in both connectivity and function. Until now these findings have not been replicated in humans. This study used high‐resolution brainstem optimized diffusion magnetic resonance imaging and probabilistic tractography to segment the human PAG into four subdivisions, based on voxel connectivity profiles. We identified four distinct subdivisions demonstrating high spatial concordance with the columns of the animal model. The resolution of these subdivisions for individual subjects permitted detailed examination of their structural connectivity without the requirement of an a priori starting location. Interestingly patterns of forebrain connectivity appear to be different to those found in nonhuman studies, whereas midbrain and hindbrain connectivity appears to be maintained. Although there are similarities in the columnar structure of the PAG subdivisions between humans and nonhuman animals, there appears to be different patterns of cortical connectivity. This suggests that the functional organization of the PAG may be different between species, and as a consequence, functional studies in nonhumans may not be directly translatable to humans. This highlights the need for focused functional studies in humans. Hum Brain Mapp 36:3459–3471, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Martyn Ezra
- Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Olivia Kate Faull
- Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Saad Jbabdi
- Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Kyle Thomas Pattinson
- Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom
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Coenen VA, Kieselbach K, Mader I, Reinacher PC. Diffusion tensor magnetic resonance imaging (DTI) tractography-guided deep brain stimulation in neuropathic pain. Acta Neurochir (Wien) 2015; 157:739-41. [PMID: 25652721 PMCID: PMC4365282 DOI: 10.1007/s00701-015-2356-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 01/12/2015] [Indexed: 11/24/2022]
Affiliation(s)
- Volker A Coenen
- Department of Stereotactic and Functional Neurosurgery, Freiburg University Medical Centre, Breisacher Strasse 64, 79106, Freiburg i.Br., Germany,
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12
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Torres CV, Manzanares R, Sola RG. Integrating Diffusion Tensor Imaging-Based Tractography into Deep Brain Stimulation Surgery: A Review of the Literature. Stereotact Funct Neurosurg 2014; 92:282-90. [DOI: 10.1159/000362937] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 04/13/2014] [Indexed: 11/19/2022]
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Pereira EAC, Wang S, Owen SLF, Aziz TZ, Green AL. Human periventricular grey somatosensory evoked potentials suggest rostrocaudally inverted somatotopy. Stereotact Funct Neurosurg 2013; 91:290-7. [PMID: 23797328 DOI: 10.1159/000348324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 01/20/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Somatosensory homunculi have been demonstrated in primary somatosensory cortex and ventral posterior thalamus but not periaqueductal and periventricular grey matter (PAVG), a therapeutic target for deep brain stimulation (DBS) in chronic pain. AIMS The study is an investigation of somatotopic representation in PAVG and assessment for a somatosensory homunculus. METHODS Five human subjects were investigated using electrical somatosensory stimulation and deep brain macroelectrode recording. DBS were implanted in the contralateral PAVG. Cutaneous arm, leg and face regions were stimulated while event-related potentials were recorded from deep brain electrodes. Electrode contact positions were mapped using MRI and brain atlas information. RESULTS Monopolar P1 somatosensory evoked potential amplitudes were highest and onset latencies shortest in contralateral caudal PAVG with facial stimulation and rostral with leg stimulation, in agreement with reported subjective sensation during intra-operative electrode advancement. CONCLUSIONS A rostrocaudally inverted somatosensory homunculus exists in the human PAVG region. Objective human evidence of PAVG somatotopy increases understanding of a brainstem region important to pain and autonomic control that is a clinical target for both pharmacological and neurosurgical therapies. Such knowledge may assist DBS target localisation for neuropathic pain syndromes related to particular body regions like brachial plexopathies, anaesthesia dolorosa and phantom limb pain.
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Affiliation(s)
- Erlick A C Pereira
- Oxford Functional Neurosurgery and Experimental Neurology Group, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
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14
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Nguyen-Thanh T, Reisert M, Anastasopoulos C, Hamzei F, Reithmeier T, Vry MS, Kiselev VG, Weyerbrock A, Mader I. Global tracking in human gliomas: a comparison with established tracking methods. Clin Neuroradiol 2013; 23:263-75. [PMID: 23329237 PMCID: PMC3834168 DOI: 10.1007/s00062-013-0198-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/02/2013] [Indexed: 11/29/2022]
Abstract
Purpose Global tracking (GT) is a recently published fibre tractography (FT) method that takes simultaneously all fibres into account during their reconstruction. The purpose of this study was to compare this new method with fibre assignment by continuous tracking (FACT) and probabilistic tractography (PT) for the detection of the corticospinal tract (CST) in patients with gliomas. Methods Tractography of the CST was performed in 17 patients with eight low grade and nine anaplastic astrocytomas located in the motor cortex or the corticospinal tract. Diffusions metrics as fractional anisotropy (FA), mean (MD), axial (AD) and radial diffusivity (RD) were obtained. The methods were additionally applied on a physical phantom to assess their accuracy. Results PT was successful in all (100 %), GT in 16 (94 %) and FACT in 15 patients (88 %). The case where GT and FACT, both, missed the CST showed the highest AD and RD, whereas the one where FACT algorithm, alone, was not successfully showed the lowest AD and RD of the group. FA was reduced on the pathologic side (FApath 0.35 ± 0.16 (mean ± SD) versus FAcontralateral 0.51 ± 0.15, pcorr < 0.03). RD was increased on the pathologic side (RDpath 0.67 ± 0.29 × 10−3 mm2/s versus RDcontralateral 0.46 ± 0.08 × 10−3 mm2/s, pcorr < 0.03). In the phantom measurement, only GT did not detect false positive fibres at fibre crossings. Conclusion PT performed well even in areas of increased diffusivities indicating a severe oedema or disintegration of tissue. FACT was also susceptible to a decrease of diffusivities and to a susceptibility artefact, where GT was robust.
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Affiliation(s)
- T Nguyen-Thanh
- Department of Neuroradiology, University Medical Centre Freiburg, Breisacher St. 64, 79106, Freiburg, Germany,
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15
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Sudhyadhom A, McGregor K, Okun MS, Foote KD, Trinastic J, Crosson B, Bova FJ. Delineation of motor and somatosensory thalamic subregions utilizing probabilistic diffusion tractography and electrophysiology. J Magn Reson Imaging 2012; 37:600-9. [PMID: 23060259 DOI: 10.1002/jmri.23861] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 09/05/2012] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To employ and compare probabilistic diffusion tractography (PDT) for the explicit localization of connections from the thalamus to somatosensory cortex (S1) and primary motor cortex (M1) / supplementary motor area (SMA) with microelectrode electrophysiology in patients undergoing deep brain stimulation (DBS) surgery. MATERIALS AND METHODS These tractography-derived connections were used to categorize voxels in the thalamus as corresponding to sensory or motor physiology. A novel model (referred to in this work as the "mixture" model) to delineate PDT-based thalamic functional subregions by thresholding fiber intensities, ie, connectivity-defined regions (CDR), was devised. Regions created using this classification method were compared with the most commonly used model (referred to in this work as the "separation" or "winner takes all" model) for defining CDRs. RESULTS Electrophysiology data corresponded better for S1 CDRs created using the mixture model for both sensory and motor cells. Separation model CDRs showed poor correspondence against electrophysiology, with few sensory cells corresponding to the S1 separation model CDR. CONCLUSION Mixture model-based CDRs may offer a significant improvement in delineation of functional subregions of subcortical structures.
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Affiliation(s)
- Atchar Sudhyadhom
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0265, USA.
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Linnman C, Moulton EA, Barmettler G, Becerra L, Borsook D. Neuroimaging of the periaqueductal gray: state of the field. Neuroimage 2011; 60:505-22. [PMID: 22197740 DOI: 10.1016/j.neuroimage.2011.11.095] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 01/18/2023] Open
Abstract
This review and meta-analysis aims at summarizing and integrating the human neuroimaging studies that report periaqueductal gray (PAG) involvement; 250 original manuscripts on human neuroimaging of the PAG were identified. A narrative review and meta-analysis using activation likelihood estimates is included. Behaviors covered include pain and pain modulation, anxiety, bladder and bowel function and autonomic regulation. Methods include structural and functional magnetic resonance imaging, functional connectivity measures, diffusion weighted imaging and positron emission tomography. Human neuroimaging studies in healthy and clinical populations largely confirm the animal literature indicating that the PAG is involved in homeostatic regulation of salient functions such as pain, anxiety and autonomic function. Methodological concerns in the current literature, including resolution constraints, imaging artifacts and imprecise neuroanatomical labeling are discussed, and future directions are proposed. A general conclusion is that PAG neuroimaging is a field with enormous potential to translate animal data onto human behaviors, but with some growing pains that can and need to be addressed in order to add to our understanding of the neurobiology of this key region.
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Affiliation(s)
- Clas Linnman
- Pain and Analgesia Imaging Neuroscience group, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA.
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Wu CWH, Vasalatiy O, Liu N, Wu H, Cheal S, Chen DY, Koretsky AP, Griffiths GL, Tootell RBH, Ungerleider LG. Development of a MR-visible compound for tracing neuroanatomical connections in vivo. Neuron 2011; 70:229-43. [PMID: 21521610 DOI: 10.1016/j.neuron.2011.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
Abstract
Traditional studies of neuroanatomical connections require injection of tracer compounds into living brains, then histology of the postmortem tissue. Here, we describe and validate a compound that reveals neuronal connections in vivo, using MRI. The classic anatomical tracer CTB (cholera-toxin subunit-B) was conjugated with a gadolinium-chelate to form GdDOTA-CTB. GdDOTA-CTB was injected into the primary somatosensory cortex (S1) or the olfactory pathway of rats. High-resolution MR images were collected at a range of time points at 11.7T and 7T. The transported GdDOTA-CTB was visible for at least 1 month post-injection, clearing within 2 months. Control injections of non-conjugated GdDOTA into S1 were not transported and cleared within 1-2 days. Control injections of Gd-Albumin were not transported either, clearing within 7 days. These MR results were verified by classic immunohistochemical staining for CTB, in the same animals. The GdDOTA-CTB neuronal transport was target specific, monosynaptic, stable for several weeks, and reproducible.
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Affiliation(s)
- Carolyn W-H Wu
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20814, USA.
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Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools. Med Biol Eng Comput 2010; 48:611-24. [DOI: 10.1007/s11517-010-0633-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
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Abstract
Functional neurosurgery involves precise surgical targeting of anatomic structures to modulate neurologic function. From its conception, advances in the surgical treatment of movement disorders have been intertwined with developments in medical imaging, culminating in the use of stereotactic magnetic resonance imaging (MRI). Meticulous attention to detail during image acquisition, direct anatomic localization, and planning of the initial surgical trajectory allows the surgeon to reach the desired anatomic and functional target with the initial trajectory in most cases, thus reducing the need for multiple passes through the brain, and the associated risk of hemorrhage and functional deficit. This philosophy is of paramount importance in a procedure that is primarily aimed at improving quality of life. Documentation of electrode contact location by means of stereotactic imaging is essential to audit surgical targeting accuracy and to further the knowledge of structure-to-function relationships within the human brain.
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Rosendal F, Frandsen J, Chakravarty MM, Bjarkam CR, Pedersen M, Sangill R, Sørensen JC. New surgical technique reduces the susceptibility artefact at air-tissue interfaces on in vivo cerebral MRI in the Göttingen minipig. Brain Res Bull 2009; 80:403-7. [PMID: 19712728 DOI: 10.1016/j.brainresbull.2009.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 07/31/2009] [Accepted: 08/17/2009] [Indexed: 10/20/2022]
Abstract
Advanced and exclusive software solutions are offered to reduce susceptibility artefacts on MRI echo-planar sequences. We present a straightforward surgical technique to reduce the cortical distortion and signal loss that normally occur using diffusion tensor imaging (DTI) of the Göttingen minipig brain. Pronounced pneumatisation of the minipig cranium causes considerable susceptibility artefacts at the air/tissue interface around the frontal sinuses. Five Göttingen minipigs had burr holes drilled through the outer lamina of the skull bilaterally at the level of bregma. The underlying frontal sinuses were filled with a suspension of an MRI-compatible alginate. DTI was obtained before and after placing the medium in the sinus, quantifying the change using mutual information and Wilcoxon's rank-sum test. Fibertracking algorithms were applied to visualize the effect of treatment. We showed that the susceptibility artefacts were reduced at the air, bone and brain interfaces and that major cortical fiberbundles could be reliably visualized. This study demonstrated that DTI fibertracking of cortical bundles in experimental animals with extensive skull pneumatisation is feasible even when advanced software is unavailable.
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Affiliation(s)
- Frederikke Rosendal
- Center for Experimental Neuroscience (CENSE), Department of Neurosurgery, University Hospital of Aarhus, DK-8000 Aarhus C, Denmark.
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