1
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Huang MX, Harrington DL, Angeles-Quinto A, Ji Z, Robb-Swan A, Huang CW, Shen Q, Hansen H, Baumgartner J, Hernandez-Lucas J, Nichols S, Jacobus J, Song T, Lerman I, Bazhenov M, Krishnan GP, Baker DG, Rao R, Lee RR. EMG-projected MEG High-Resolution Source Imaging of Human Motor Execution: Brain-Muscle Coupling above Movement Frequencies. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.06.23.23291825. [PMID: 37425691 PMCID: PMC10327237 DOI: 10.1101/2023.06.23.23291825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Magnetoencephalography (MEG) is a non-invasive functional imaging technique for pre-surgical mapping. However, movement-related MEG functional mapping of primary motor cortex (M1) has been challenging in presurgical patients with brain lesions and sensorimotor dysfunction due to the large numbers of trails needed to obtain adequate signal to noise. Moreover, it is not fully understood how effective the brain communication is with the muscles at frequencies above the movement frequency and its harmonics. We developed a novel Electromyography (EMG)-projected MEG source imaging technique for localizing M1 during ~1 minute recordings of left and right self-paced finger movements (~1 Hz). High-resolution MEG source images were obtained by projecting M1 activity towards the skin EMG signal without trial averaging. We studied delta (1-4 Hz), theta (4-7 Hz), alpha (8-12 Hz), beta (15-30 Hz), and gamma (30-90 Hz) bands in 13 healthy participants (26 datasets) and two presurgical patients with sensorimotor dysfunction. In healthy participants, EMG-projected MEG accurately localized M1 with high accuracy in delta (100.0%), theta (100.0%), and beta (76.9%) bands, but not alpha (34.6%) and gamma (0.0%) bands. Except for delta, all other frequency bands were above the movement frequency and its harmonics. In both presurgical patients, M1 activity in the affected hemisphere was also accurately localized, despite highly irregular EMG movement patterns in one patient. Altogether, our EMG-projected MEG imaging approach is highly accurate and feasible for M1 mapping in presurgical patients. The results also provide insight into movement related brain-muscle coupling above the movement frequency and its harmonics.
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Affiliation(s)
- Ming-Xiong Huang
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
- Department of Radiology, University of California, San Diego, CA, USA
- Department of Electrical and Computer Engineering, University of California, San Diego, CA, USA
| | - Deborah L. Harrington
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
- Department of Radiology, University of California, San Diego, CA, USA
| | | | - Zhengwei Ji
- Department of Radiology, University of California, San Diego, CA, USA
| | - Ashley Robb-Swan
- Department of Radiology, University of California, San Diego, CA, USA
| | - Charles W. Huang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Qian Shen
- Department of Radiology, University of California, San Diego, CA, USA
| | - Hayden Hansen
- Department of Radiology, University of California, San Diego, CA, USA
| | - Jared Baumgartner
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
| | | | - Sharon Nichols
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Joanna Jacobus
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Tao Song
- Department of Radiology, University of California, San Diego, CA, USA
| | - Imanuel Lerman
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
| | - Maksim Bazhenov
- Department of Medicine, University of California, San Diego, CA, USA
| | - Giri P Krishnan
- Department of Medicine, University of California, San Diego, CA, USA
| | - Dewleen G. Baker
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
- Department of Psychiatry, University of California, San Diego, CA, USA
- VA Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, San Diego, CA, USA
| | - Ramesh Rao
- Department of Electrical and Computer Engineering, University of California, San Diego, CA, USA
| | - Roland R. Lee
- Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA
- Department of Radiology, University of California, San Diego, CA, USA
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2
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Washington KM, Solari MG, Zanoun RR, Kwegyir-Afful EE, Su AJA, Carvell GE, Lee WPA, Simons DJ. Cortical reintegration after facial allotransplantation. J Neurophysiol 2023; 129:421-430. [PMID: 36542405 DOI: 10.1152/jn.00349.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Neural plasticity of the brain or its ability to reorganize following injury has likely coincided with the successful clinical correction of severe deformity by facial transplantation since 2005. In this study, we present the cortical reintegration outcomes following syngeneic hemifacial vascularized composite allograft (VCA) in a small animal model. Specifically, changes in the topographic organization and unit response properties of the rodent whisker-barrel somatosensory system were assessed following hemifacial VCA. Clear differences emerged in the barrel-cortex system when comparing naïve and hemiface transplanted animals. Neurons in the somatosensory cortex of transplanted rats had decreased sensitivity albeit increased directional sensitivity compared with naïve rats and evoked responses in transplanted animals were more temporally dispersed. In addition, receptive fields were often topographically mismatched with the indication that the mismatched topography reorganized within adjacent barrel (same row-arc bias following hemifacial transplant). These results suggest subcortical changes in the thalamus and/or brainstem play a role in hemifacial transplantation cortical plasticity and demonstrate the discrete and robust data that can be derived from this clinically relevant small animal VCA model for use in optimizing postsurgical outcomes.NEW & NOTEWORTHY Robust rodent hemifacial transplant model was used to record functional changes in somatosensory cortex after transplantation. Neurons in the somatosensory cortex of face transplant recipients had decreased sensitivity to stimulation of whiskers with increased directional sensitivity vs. naive rats. Transplant recipient cortical unit response was more dispersed in temporary vs. naive rats. Despite histological similarities to naive cortices, transplant recipient cortices had a mix of topographically appropriate and inappropriate whiskered at barrel cortex relationships.
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Affiliation(s)
- Kia M Washington
- Department of Plastic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Surgery, University of Colorado School of Medicine, CU Anschutz Medical Campus, Aurora, Colorado
| | - Mario G Solari
- Department of Plastic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Rami R Zanoun
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ernest E Kwegyir-Afful
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - An-Jey A Su
- Department of Plastic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Surgery, University of Colorado School of Medicine, CU Anschutz Medical Campus, Aurora, Colorado
| | - George E Carvell
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - W P Andrew Lee
- Department of Plastic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Daniel J Simons
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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3
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Gaetz W, Graci V, Falciani C, Sanders O, Prosser LA. A MEG compatible, interactive IR game paradigm for the study of visuomotor reach-to-target movements in young children and clinical populations: The Target-Touch Motor Task. J Neurosci Methods 2022; 380:109675. [PMID: 35872154 DOI: 10.1016/j.jneumeth.2022.109675] [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: 07/22/2021] [Revised: 06/17/2022] [Accepted: 07/11/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND The conventional focus on discrete finger movements (i.e., index finger flexion or button-box key presses) has been an effective method to study neuromotor control using magnetoencephalography (MEG). However, this approach is challenging for young children and not possible for some people with physical disability. NEW METHOD We have developed a novel, interactive MEG compatible reach-to-target task to investigate neuromotor function, specifically for use with young children. We used an infrared touch-screen frame to detect responses to targets presented using custom software. The game can be played using a conventional computer monitor or during MEG recordings via projector. We termed this game the Target-Touch Motor Task (TTMT). RESULTS We demonstrate that the TTMT is a feasible motor task for use with young children including children with physical impairments. TTMT response-to-target trial counts are also comparable to conventional methods. Artifacts from the touch screen, while present > 100 Hz, did not affect MEG source analysis in the beta band (14-30 Hz). MEG responses during TTMT game play reveal robust cortical activity from expected areas of motor cortex as typically observed following movements of the upper limb. COMPARISON WITH EXISTING METHOD(S) The TTMT paradigm allows participation by individuals with a broad range of motor abilities on a reach-to-target' functional task rather than conventional tasks focusing on discrete finger movements. CONCLUSIONS The TTMT is well suited for young children and successfully activates expected motor cortical areas. The TTMT opens-up new opportunities for the assessment of motor function across the lifespan, including for children with physical limitations.
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Affiliation(s)
- William Gaetz
- Lurie Family Foundations' MEG Imaging Center, Dept. of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Center for Injury Research and Prevention (CIRP), The Children's Hospital of Philadelphia, USA; Dept. of Radiology, Perelman School of Medicine, University of Pennsylvania, PA, USA.
| | - Valentina Graci
- Neuromotor Performance Laboratory (NMPL), Center for Rehabilitation, The Children's Hospital of Philadelphia, PA, USA; Center for Injury Research and Prevention (CIRP), The Children's Hospital of Philadelphia, USA; School of Biomedical Engineering, Science and Health System, Drexel University, PA, USA
| | - Clayton Falciani
- Neuromotor Performance Laboratory (NMPL), Center for Rehabilitation, The Children's Hospital of Philadelphia, PA, USA
| | - Ozell Sanders
- Neuromotor Performance Laboratory (NMPL), Center for Rehabilitation, The Children's Hospital of Philadelphia, PA, USA
| | - Laura A Prosser
- Neuromotor Performance Laboratory (NMPL), Center for Rehabilitation, The Children's Hospital of Philadelphia, PA, USA; Dept. of Pediatrics, Perelman School of Medicine, University of Pennsylvania, PA, USA
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4
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Liu L, Ren J, Li Z, Yang C. A review of MEG dynamic brain network research. Proc Inst Mech Eng H 2022; 236:763-774. [PMID: 35465768 DOI: 10.1177/09544119221092503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The dynamic description of neural networks has attracted the attention of researchers for dynamic networks may carry more information compared with resting-state networks. As a non-invasive electrophysiological data with high temporal and spatial resolution, magnetoencephalogram (MEG) can provide rich information for the analysis of dynamic functional brain networks. In this review, the development of MEG brain network was summarized. Several analysis methods such as sliding window, Hidden Markov model, and time-frequency based methods used in MEG dynamic brain network studies were discussed. Finally, the current research about multi-modal brain network analysis and their applications with MEG neurophysiology, which are prospected to be one of the research directions in the future, were concluded.
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Affiliation(s)
- Lu Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Jiechuan Ren
- Department of Internal Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhimei Li
- Department of Internal Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chunlan Yang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
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5
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Jaatela J, Aydogan DB, Nurmi T, Vallinoja J, Piitulainen H. Identification of Proprioceptive Thalamocortical Tracts in Children: Comparison of fMRI, MEG, and Manual Seeding of Probabilistic Tractography. Cereb Cortex 2022; 32:3736-3751. [PMID: 35040948 PMCID: PMC9433422 DOI: 10.1093/cercor/bhab444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 11/16/2022] Open
Abstract
Studying white matter connections with tractography is a promising approach to understand the development of different brain processes, such as proprioception. An emerging method is to use functional brain imaging to select the cortical seed points for tractography, which is considered to improve the functional relevance and validity of the studied connections. However, it is unknown whether different functional seeding methods affect the spatial and microstructural properties of the given white matter connection. Here, we compared functional magnetic resonance imaging, magnetoencephalography, and manual seeding of thalamocortical proprioceptive tracts for finger and ankle joints separately. We showed that all three seeding approaches resulted in robust thalamocortical tracts, even though there were significant differences in localization of the respective proprioceptive seed areas in the sensorimotor cortex, and in the microstructural properties of the obtained tracts. Our study shows that the selected functional or manual seeding approach might cause systematic biases to the studied thalamocortical tracts. This result may indicate that the obtained tracts represent different portions and features of the somatosensory system. Our findings highlight the challenges of studying proprioception in the developing brain and illustrate the need for using multimodal imaging to obtain a comprehensive view of the studied brain process.
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Affiliation(s)
- Julia Jaatela
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo FI-02150, Finland
| | - Dogu Baran Aydogan
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo FI-02150, Finland
- Department of Psychiatry, Helsinki University Hospital, Helsinki FI-00029, Finland
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio FI-70211, Finland
| | - Timo Nurmi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo FI-02150, Finland
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä FI-40014, Finland
| | - Jaakko Vallinoja
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo FI-02150, Finland
| | - Harri Piitulainen
- Address correspondence to Harri Piitulainen, associate professor, Harri Piitulainen, Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. BOX 35, FI-40014, Finland.
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6
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Yang JYM, Yeh CH, Poupon C, Calamante F. Diffusion MRI tractography for neurosurgery: the basics, current state, technical reliability and challenges. Phys Med Biol 2021; 66. [PMID: 34157706 DOI: 10.1088/1361-6560/ac0d90] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/22/2021] [Indexed: 01/20/2023]
Abstract
Diffusion magnetic resonance imaging (dMRI) tractography is currently the only imaging technique that allows for non-invasive delineation and visualisation of white matter (WM) tractsin vivo,prompting rapid advances in related fields of brain MRI research in recent years. One of its major clinical applications is for pre-surgical planning and intraoperative image guidance in neurosurgery, where knowledge about the location of WM tracts nearby the surgical target can be helpful to guide surgical resection and optimise post-surgical outcomes. Surgical injuries to these WM tracts can lead to permanent neurological and functional deficits, making the accuracy of tractography reconstructions paramount. The quality of dMRI tractography is influenced by many modifiable factors, ranging from MRI data acquisition through to the post-processing of tractography output, with the potential of error propagation based on decisions made at each and subsequent processing steps. Research over the last 25 years has significantly improved the anatomical accuracy of tractography. An updated review about tractography methodology in the context of neurosurgery is now timely given the thriving research activities in dMRI, to ensure more appropriate applications in the clinical neurosurgical realm. This article aims to review the dMRI physics, and tractography methodologies, highlighting recent advances to provide the key concepts of tractography-informed neurosurgery, with a focus on the general considerations, the current state of practice, technical challenges, potential advances, and future demands to this field.
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Affiliation(s)
- Joseph Yuan-Mou Yang
- Department of Neurosurgery, The Royal Children's Hospital, Melbourne, Australia.,Neuroscience Research, Murdoch Children's Research Institute, Melbourne, Australia.,Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, Australia
| | - Chun-Hung Yeh
- Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Child and Adolescent Psychiatry, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
| | - Cyril Poupon
- NeuroSpin, Frédéric Joliot Life Sciences Institute, CEA, CNRS, Paris-Saclay University, Gif-sur-Yvette, France
| | - Fernando Calamante
- The University of Sydney, Sydney Imaging, Sydney, Australia.,The University of Sydney, School of Biomedical Engineering, Sydney, Australia
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7
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Ille S, Krieg SM. Functional Mapping for Glioma Surgery, Part 1: Preoperative Mapping Tools. Neurosurg Clin N Am 2020; 32:65-74. [PMID: 33223027 DOI: 10.1016/j.nec.2020.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although intraoperative mapping of brain areas was shown to promote greater extent of resection and reduce functional deficits, this was shown only recently for some noninvasive techniques. Yet, proper surgical planning, indication, and patient consultation require reliable noninvasive techniques. Because functional magnetic resonance imaging, tractography, and neurophysiologic methods like navigated transcranial magnetic stimulation and magnetoencephalography allow identifying eloquent areas prior to resective surgery and tailor the surgical approach, this article provides an overview on the individual strengths and limitations of each modality.
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Affiliation(s)
- Sebastian Ille
- Department of Neurosurgery, Technical University of Munich, Germany, School of Medicine, Klinikum rechts der Isar, Ismaninger Strasse 22, Munich 81675, Germany
| | - Sandro M Krieg
- Department of Neurosurgery, Technical University of Munich, Germany, School of Medicine, Klinikum rechts der Isar, Ismaninger Strasse 22, Munich 81675, Germany.
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8
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Stephen JM, Solis I, Janowich J, Stern M, Frenzel MR, Eastman JA, Mills MS, Embury CM, Coolidge NM, Heinrichs-Graham E, Mayer A, Liu J, Wang YP, Wilson TW, Calhoun VD. The Developmental Chronnecto-Genomics (Dev-CoG) study: A multimodal study on the developing brain. Neuroimage 2020; 225:117438. [PMID: 33039623 DOI: 10.1016/j.neuroimage.2020.117438] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/07/2020] [Accepted: 10/05/2020] [Indexed: 01/10/2023] Open
Abstract
Brain development has largely been studied through unimodal analysis of neuroimaging data, providing independent results for structural and functional data. However, structure clearly impacts function and vice versa, pointing to the need for performing multimodal data collection and analysis to improve our understanding of brain development, and to further inform models of typical and atypical brain development across the lifespan. Ultimately, such models should also incorporate genetic and epigenetic mechanisms underlying brain structure and function, although currently this area is poorly specified. To this end, we are reporting here a multi-site, multi-modal dataset that captures cognitive function, brain structure and function, and genetic and epigenetic measures to better quantify the factors that influence brain development in children originally aged 9-14 years. Data collection for the Developmental Chronnecto-Genomics (Dev-CoG) study (http://devcog.mrn.org/) includes cognitive, emotional, and social performance scales, structural and functional MRI, diffusion MRI, magnetoencephalography (MEG), and saliva collection for DNA analysis of single nucleotide polymorphisms (SNPs) and DNA methylation patterns. Across two sites (The Mind Research Network and the University of Nebraska Medical Center), data from over 200 participants were collected and these children were re-tested annually for at least 3 years. The data collection protocol, sample demographics, and data quality measures for the dataset are presented here. The sample will be made freely available through the collaborative informatics and neuroimaging suite (COINS) database at the conclusion of the study.
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Affiliation(s)
- J M Stephen
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States.
| | - I Solis
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States; Department of Psychology, University of New Mexico, Albuquerque, NM, United States
| | - J Janowich
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States; Department of Psychology, University of New Mexico, Albuquerque, NM, United States
| | - M Stern
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States; Department of Psychology, University of New Mexico, Albuquerque, NM, United States
| | - M R Frenzel
- University of Nebraska Medical Center, Omaha, NE, United States
| | - J A Eastman
- University of Nebraska Medical Center, Omaha, NE, United States
| | - M S Mills
- University of Nebraska Medical Center, Omaha, NE, United States
| | - C M Embury
- University of Nebraska Medical Center, Omaha, NE, United States
| | - N M Coolidge
- University of Nebraska Medical Center, Omaha, NE, United States
| | | | - A Mayer
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States
| | - J Liu
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States
| | - Y P Wang
- Tulane University, New Orleans, LA, United States
| | - T W Wilson
- University of Nebraska Medical Center, Omaha, NE, United States
| | - V D Calhoun
- The Mind Research Network a division of Lovelace Biomedical Research Institute, Albuquerque, NM, United States; Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States; Tri-institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State University, Georgia Institute of Technology, Emory University, Atlanta, GA, United States
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9
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Panesar SS, Abhinav K, Yeh FC, Jacquesson T, Collins M, Fernandez-Miranda J. Tractography for Surgical Neuro-Oncology Planning: Towards a Gold Standard. Neurotherapeutics 2019; 16:36-51. [PMID: 30542904 PMCID: PMC6361069 DOI: 10.1007/s13311-018-00697-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Magnetic resonance imaging tractography permits in vivo visualization of white matter structures. Aside from its academic value, tractography has been proven particularly useful to neurosurgeons for preoperative planning. Preoperative tractography permits both qualitative and quantitative analyses of tumor effects upon surrounding white matter, allowing the surgeon to specifically tailor their operative approach. Despite its benefits, there is controversy pertaining to methodology, implementation, and interpretation of results in this context. High-definition fiber tractography (HDFT) is one of several non-tensor tractography approaches permitting visualization of crossing white matter trajectories at high resolutions, dispensing with the well-known shortcomings of diffusion tensor imaging (DTI) tractography. In this article, we provide an overview of the advantages of HDFT in a neurosurgical context, derived from our considerable experience implementing the technique for academic and clinical purposes. We highlight nuances of qualitative and quantitative approaches to using HDFT for brain tumor surgery planning, and integration of tractography with complementary operative adjuncts, and consider areas requiring further research.
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Affiliation(s)
- Sandip S Panesar
- Department of Neurosurgery, Stanford University, 300 Pasteur Drive, Palo Alto, CA, 94304, USA
| | - Kumar Abhinav
- Department of Neurosurgery, Stanford University, 300 Pasteur Drive, Palo Alto, CA, 94304, USA
| | - Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Timothée Jacquesson
- CHU de Lyon - Hôpital Neurologique et Neurochirurgical Pierre Wertheimer, Lyon, France
| | - Malie Collins
- Department of Neurosurgery, Stanford University, 300 Pasteur Drive, Palo Alto, CA, 94304, USA
| | - Juan Fernandez-Miranda
- Department of Neurosurgery, Stanford University, 300 Pasteur Drive, Palo Alto, CA, 94304, USA.
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10
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Timoney N, Rutka JT. Recent Advances in Epilepsy Surgery and Achieving Best Outcomes Using High-Frequency Oscillations, Diffusion Tensor Imaging, Magnetoencephalography, Intraoperative Neuromonitoring, Focal Cortical Dysplasia, and Bottom of Sulcus Dysplasia. Neurosurgery 2017; 64:1-10. [DOI: 10.1093/neuros/nyx239] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/27/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nessa Timoney
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky, USA
- Department of Surgery, Division of Ne-urosurgery, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - James T. Rutka
- Department of Neurosurgery, University of Kentucky, Lexington, Kentucky, USA
- Department of Surgery, Division of Ne-urosurgery, The Hospital for Sick Children, University of Toronto, Toronto, Canada
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11
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Weiss Lucas C, Tursunova I, Neuschmelting V, Nettekoven C, Oros-Peusquens AM, Stoffels G, Faymonville AM, Jon SN, Langen KJ, Lockau H, Goldbrunner R, Grefkes C. Functional MRI vs. navigated TMS to optimize M1 seed volume delineation for DTI tractography. A prospective study in patients with brain tumours adjacent to the corticospinal tract. NEUROIMAGE-CLINICAL 2016; 13:297-309. [PMID: 28050345 PMCID: PMC5192048 DOI: 10.1016/j.nicl.2016.11.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/18/2016] [Accepted: 11/19/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND DTI-based tractography is an increasingly important tool for planning brain surgery in patients suffering from brain tumours. However, there is an ongoing debate which tracking approaches yield the most valid results. Especially the use of functional localizer data such as navigated transcranial magnetic stimulation (nTMS) or functional magnetic resonance imaging (fMRI) seem to improve fibre tracking data in conditions where anatomical landmarks are less informative due to tumour-induced distortions of the gyral anatomy. We here compared which of the two localizer techniques yields more plausible results with respect to mapping different functional portions of the corticospinal tract (CST) in brain tumour patients. METHODS The CSTs of 18 patients with intracranial tumours in the vicinity of the primary motor area (M1) were investigated by means of deterministic DTI. The core zone of the tumour-adjacent hand, foot and/or tongue M1 representation served as cortical regions of interest (ROIs). M1 core zones were defined by both the nTMS hot-spots and the fMRI local activation maxima. In addition, for all patients, a subcortical ROI at the level of the inferior anterior pons was implemented into the tracking algorithm in order to improve the anatomical specificity of CST reconstructions. As intra-individual control, we additionally tracked the CST of the hand motor region of the unaffected, i.e., non-lesional hemisphere, again comparing fMRI and nTMS M1 seeds. The plausibility of the fMRI-ROI- vs. nTMS-ROI-based fibre trajectories was assessed by a-priori defined anatomical criteria. Moreover, the anatomical relationship of different fibre courses was compared regarding their distribution in the anterior-posterior direction as well as their location within the posterior limb of the internal capsule (PLIC). RESULTS Overall, higher plausibility rates were observed for the use of nTMS- as compared to fMRI-defined cortical ROIs (p < 0.05) in tumour vicinity. On the non-lesional hemisphere, however, equally good plausibility rates (100%) were observed for both localizer techniques. fMRI-originated fibres generally followed a more posterior course relative to the nTMS-based tracts (p < 0.01) in both the lesional and non-lesional hemisphere. CONCLUSION NTMS achieved better tracking results than fMRI in conditions when the cortical tract origin (M1) was located in close vicinity to a brain tumour, probably influencing neurovascular coupling. Hence, especially in situations with altered BOLD signal physiology, nTMS seems to be the method of choice in order to identify seed regions for CST mapping in patients.
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Key Words
- APB, Abductor pollicis brevis muscle
- BOLD, Blood-oxygenation-level dependent
- CST
- CST, Corticospinal tract
- DCS, Direct cortical stimulation
- DTI, Diffusion tensor imaging
- Deterministic
- EF, Electric field
- EMG, Electromyography
- FA(T), Fractional anisotropy (threshold)
- FACT, Fibre assignment by continuous tracking
- FOV, Field-of-view
- FWE, Family-wise error
- KPS, Karnofsky performance scale
- LT, Lateral tongue muscle, anterior third
- M1, Primary motor cortex
- MEP, Motor-evoked potential
- MFL, Minimal fibre length
- MPRAGE, Magnetization prepared rapid acquisition gradient echo (T1 MR seq.)
- OR, Odd's ratio
- PLIC, Posterior limb of the internal capsule
- PM, Plantar muscle
- Pyramidal tract
- RMT, Resting motor threshold
- ROI
- ROI, Region-of-interest
- SD, Standard deviation
- SE, Standard error
- Somatotopic
- X-sq, X-squared (Pearson's chi-square test)
- dMRI, Diffusion magnetic resonance imaging (i.e., diffusion-weighted imaging, DWI)
- fMRI
- fMRI, Functional magnetic resonance imaging
- nTMS
- nTMS, Neuronavigated transcranial magnetic stimulation
- pxsq, p-value according to Pearson's chi-square test
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Affiliation(s)
| | - Irada Tursunova
- University of Cologne, Center of Neurosurgery, 50924 Cologne, Germany
| | | | | | | | - Gabriele Stoffels
- Institute of Neuroscience and Medicine, Research Centre Jülich, 52425 Jülich, Germany
| | | | - Shah N Jon
- Institute of Neuroscience and Medicine, Research Centre Jülich, 52425 Jülich, Germany; RWTH Aachen University, University Clinic Aachen, Departments of Nuclear Medicine and Neurology, 52074 Aachen, Germany; Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Victoria, Australia; Monash Institute of Medical Engineering, Monash University, Melbourne, Victoria, Australia; Monash Biomedical Imaging, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Karl Josef Langen
- Institute of Neuroscience and Medicine, Research Centre Jülich, 52425 Jülich, Germany; RWTH Aachen University, University Clinic Aachen, Departments of Nuclear Medicine and Neurology, 52074 Aachen, Germany
| | - Hannah Lockau
- University of Cologne, Department of Radiology, 50937 Cologne, Germany
| | | | - Christian Grefkes
- Institute of Neuroscience and Medicine, Research Centre Jülich, 52425 Jülich, Germany; University of Cologne, Department of Neurology, 50924 Cologne, Germany
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12
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Coppola A, Tramontano V, Basaldella F, Arcaro C, Squintani G, Sala F. Intra-operative neurophysiological mapping and monitoring during brain tumour surgery in children: an update. Childs Nerv Syst 2016; 32:1849-59. [PMID: 27659828 DOI: 10.1007/s00381-016-3180-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 07/05/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Over the past decade, the reluctance to operate in eloquent brain areas has been reconsidered in the light of the advent of new peri-operative functional neuroimaging techniques and new evidence from neuro-oncology. To maximise tumour resection while minimising morbidity should be the goal of brain surgery in children as much as it is in adults, and preservation of brain functions is critical in the light of the increased survival and the expectations in terms of quality of life. DISCUSSION Intra-operative neurophysiology is the gold standard to localise and preserve brain functions during surgery and is increasingly used in paediatric neurosurgery. Yet, the developing nervous system has peculiar characteristics in terms of anatomical and physiological maturation, and some technical aspects need to be tailored for its use in children, especially in infants. This paper will review the most recent advances in the field of intra-operative neurophysiology (ION) techniques during brain surgery, focussing on those aspects that are relevant to the paediatric neurosurgery practice.
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Affiliation(s)
- Angela Coppola
- Pediatric Neurosurgery, Institute of Neurosurgery, University Hospital, Verona, Italy
| | | | | | - Chiara Arcaro
- Division of Neurology, University Hospital, Verona, Italy
| | | | - Francesco Sala
- Pediatric Neurosurgery, Institute of Neurosurgery, University Hospital, Verona, Italy. .,Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
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Clinical considerations and surgical approaches for low-grade gliomas in deep hemispheric locations: insular lesions. Childs Nerv Syst 2016; 32:1875-93. [PMID: 27659830 DOI: 10.1007/s00381-016-3183-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 07/06/2016] [Indexed: 12/31/2022]
Abstract
Insula and paralimbic region represent a common location for gliomas in adulthood. However, limbic and paralimbic tumors are rare in children. Reports of pediatric insular tumors are scarce in literature, and most of them are included in adult's series, so their management and outcome can be outlined only after extracting data from these reports. Due to their predominantly low grade, they usually have a benign course for some time, what make them ideal candidates for total resection. However, their intricate location and spread to key areas, including the temporal lobe, make them a surgical challenge. The transsylvian route, with or without resection of the frontal and/or temporal operculae, which requires exposure of part or all of the insula is commonly selected for insular tumor approaches. Intraoperative functional mapping is a standard procedure for resection of central region tumors in adults. In children and young individuals, awake craniotomy is not always possible and surgical planning usually relay on functional and anatomical preoperative studies. The main goal when approaching an insular tumor is to achieve the largest extent of resection to increase overall patient survival while preserving the functional status, minimizing postoperative morbidity and increasing the quality of life. The extent of resection seems to be correlated also with the control of associated (and usually intractable) epilepsy.
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Raybaud C. Cerebral hemispheric low-grade glial tumors in children: preoperative anatomic assessment with MRI and DTI. Childs Nerv Syst 2016; 32:1799-811. [PMID: 27659823 DOI: 10.1007/s00381-016-3188-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 07/07/2016] [Indexed: 12/01/2022]
Abstract
PURPOSE The aims of this study are to analyze how the nature and the behavior of low-grade glial tumors (LGGT) in children may correlate with the anatomy of the cerebral hemispheres and to evaluate the consequent impact of diffusion tensor imaging (DTI) techniques in the presurgical assessment. METHODS This is a combined review of a series of 155 cases of LGGT and of the recent literature on the subject. RESULTS The cases retrieved from our data bank were divided in central hemispheric tumors (basal ganglia and thalami) (36 cases), glioneuronal cortical-based tumors (49 cases), and glial tumors of the cerebral mantle (70 cases). A close correlation was found in the thalamus between the primary location of the tumor (juxta-ventricular, inferior, lateral, bilateral) and its extension (ventricular lumen, midbrain and mesial temporal, globus pallidus, respectively) which may relate to the connectivity. Among the glioneuronal tumors, most gangliogliomas were located in the temporal lobe and especially in the mesial temporal structures. In addition, the morphologic feature of the ganglioglioma was different there from the neocortical areas. As a complementary approach, DTI data may assist in evaluating the structure and the extension of the LGGT, in addition to planning the surgical strategy. CONCLUSIONS In the cerebral hemispheres like in the rest of the central nervous system, there is some degree of correlation between the anatomy and the nature, appearance, and behavior of the LGGT in children.
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Affiliation(s)
- Charles Raybaud
- Division of Neuroradiology, Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON, M5G1X8, Canada.
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15
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Martinez-Rios C, McAndrews MP, Logan W, Krings T, Lee D, Widjaja E. MRI in the evaluation of localization-related epilepsy. J Magn Reson Imaging 2016; 44:12-22. [PMID: 27115073 DOI: 10.1002/jmri.25269] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/28/2016] [Indexed: 11/06/2022] Open
Abstract
This article covers the MRI evaluation of patients with epilepsy, with a focus on neuroimaging in those with localization-related epilepsy who may be potential epilepsy surgery candidates. The article includes structural MRI to identify a lesion, functional MRI to identify the eloquent cortex and diffusion tensor imaging to identify the eloquent white matter tracts. We consider the equipment, protocol or procedures, and reporting of MRI in patients with epilepsy. Recommendations for both adult and pediatric patients are described for protocols and procedures. The authors hope that this article will provide a standardized approach for clinical imaging of patients with suspected localization-related epilepsy who may be evaluated for epilepsy surgery. J. Magn. Reson. Imaging 2016.
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Affiliation(s)
| | | | - William Logan
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Timo Krings
- University Health Network, Toronto, Ontario, Canada
| | - Donald Lee
- London Health Sciences Center, London, Ontario, Canada
| | - Elysa Widjaja
- Department of Radiology, Hospital for Sick Children, Toronto, Ontario, Canada
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16
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Niu C, Liu X, Yang Y, Zhang K, Min Z, Wang M, Li W, Guo L, Lin P, Zhang M. Assessing Region of Interest Schemes for the Corticospinal Tract in Patients With Brain Tumors. Medicine (Baltimore) 2016; 95:e3189. [PMID: 27015212 PMCID: PMC4998407 DOI: 10.1097/md.0000000000003189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) techniques are widely used for identifying the corticospinal tract (CST) white matter pathways as part of presurgical planning. However, mass effects in patients with brain tumors tend to cause anatomical distortions and compensatory functional reorganization of the cortex, which may lead to inaccurate mapping of white matter tracts. To overcome these problems, we compared different region-of-interest (ROI) selection schemes to track CST fibers in patients with brain tumors. Our study investigated the CSTs of 16 patients with intracranial tumors. The patients were classified into 3 subgroups according to the spatial relationships of the lesion and the primary motor cortex (PMC)/internal capsule. Specifically, we investigated the key factors that cause distorted tractography in patients with tumors. We compared 3 CST tractography methods that used different ROI selection schemes. The results indicate that CST fiber tracking methods based only on anatomical ROIs could possibly lead to distortions near the PMC region and may be unable to effectively localize the PMC. In contrast, the dual ROI method, which uses ROIs that have been selected from both blood oxygen level-dependent functional MRI (BOLD-fMRI) activation and anatomical landmarks, enabled the tracking of fibers to the motor cortex. The results demonstrate that the dual ROI method can localize the entire CST fiber pathway and can accurately describe the spatial relationships of CST fibers relative to the tumor. These results illustrate the reliability of using fMRI-guided DTT in patients with tumors. The combination of fMRI and anatomical information enhances the identification of tracts of interest in brains with anatomical deformations, which provides neurosurgeons with a more accurate approach for visualizing and localizing white matter fiber tracts in patients with brain tumors. This approach enhances surgical performance and perserves brain function.
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Affiliation(s)
- Chen Niu
- From the Department of Medical Imaging, The First Affiliated Hospital of Xi'An Jiaotong University, Xi'an, Shaanxi (CN, MG, WL, LG, MZ); Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Biomedical Engineering, Xi'an Jiaotong University, Xi'an (XL); School of Information Technology, Jiangxi University of Finance and Economics, Nanchang, People's Republic of China (YY); Department of Electronics Engineering, Northwestern Polytechnical University, Xi'an (KZ); Department of Neurosurgey, First Affiliated Hospital of Xi'An Jiaotong University, Xi'an, Shaanxi (MW); Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Biomedical Engineering, Xi'an Jiaotong University, Xi'an (PL); and Department of Medical Imaging, The First Affiliated Hospital of Xi'An Jiaotong University, Xi'an (MZ), Shaanxi, China
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17
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Irimia A, Erhart MJ, Brown TT. Variability of magnetoencephalographic sensor sensitivity measures as a function of age, brain volume and cortical area. Clin Neurophysiol 2014; 125:1973-84. [PMID: 24589347 DOI: 10.1016/j.clinph.2014.01.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 01/21/2014] [Accepted: 01/29/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To assess the feasibility and appropriateness of magnetoencephalography (MEG) for both adult and pediatric studies, as well as for the developmental comparison of these factors across a wide range of ages. METHODS For 45 subjects with ages from 1 to 24years (infants, toddlers, school-age children and young adults), lead fields (LFs) of MEG sensors are computed using anatomically realistic boundary element models (BEMs) and individually-reconstructed cortical surfaces. Novel metrics are introduced to quantify MEG sensor focality. RESULTS The variability of MEG focality is graphed as a function of brain volume and cortical area. Statistically significant differences in total cerebral volume, cortical area, MEG global sensitivity and LF focality are found between age groups. CONCLUSIONS Because MEG focality and sensitivity differ substantially across the age groups studied, the cortical LF maps explored here can provide important insights for the examination and interpretation of MEG signals from early childhood to young adulthood. SIGNIFICANCE This is the first study to (1) investigate the relationship between MEG cortical LFs and brain volume as well as cortical area across development, and (2) compare LFs between subjects with different head sizes using detailed cortical reconstructions.
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Affiliation(s)
- Andrei Irimia
- Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA 90032, USA
| | - Matthew J Erhart
- Multimodal Imaging Laboratory, University of California, San Diego, CA 92037, USA; Department of Radiology, University of California, San Diego, CA 92037, USA
| | - Timothy T Brown
- Multimodal Imaging Laboratory, University of California, San Diego, CA 92037, USA; Department of Neurosciences, University of California, San Diego, CA 92037, USA.
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18
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Abstract
White matter matures with age and is important for the efficient transmission of neuronal signals. Consequently, white matter growth may underlie the development of cognitive processes important for learning, including the speed of information processing. To dissect the relationship between white matter structure and information processing speed, we administered a reaction time task (finger abduction in response to visual cue) to 27 typically developing, right-handed children aged 4 to 13. Magnetoencephalography and Diffusion Tensor Imaging were used to delineate white matter connections implicated in visual-motor information processing. Fractional anisotropy (FA) and radial diffusivity (RD) of the optic radiation in the left hemisphere, and FA and mean diffusivity (MD) of the optic radiation in the right hemisphere changed significantly with age. MD and RD decreased with age in the right inferior fronto-occipital fasciculus, and bilaterally in the cortico-spinal tracts. No age-related changes were evident in the inferior longitudinal fasciculus. FA of the cortico-spinal tract in the left hemisphere and MD of the inferior fronto-occipital fasciculus of the right hemisphere contributed uniquely beyond the effect of age in accounting for reaction time performance of the right hand. Our findings support the role of white matter maturation in the development of information processing speed.
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Stephen JM, Coffman BA, Jung RE, Bustillo JR, Aine CJ, Calhoun VD. Using joint ICA to link function and structure using MEG and DTI in schizophrenia. Neuroimage 2013; 83:418-30. [PMID: 23777757 DOI: 10.1016/j.neuroimage.2013.06.038] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 06/05/2013] [Accepted: 06/07/2013] [Indexed: 11/19/2022] Open
Abstract
In this study we employed joint independent component analysis (jICA) to perform a novel multivariate integration of magnetoencephalography (MEG) and diffusion tensor imaging (DTI) data to investigate the link between function and structure. This model-free approach allows one to identify covariation across modalities with different temporal and spatial scales [temporal variation in MEG and spatial variation in fractional anisotropy (FA) maps]. Healthy controls (HC) and patients with schizophrenia (SP) participated in an auditory/visual multisensory integration paradigm to probe cortical connectivity in schizophrenia. To allow direct comparisons across participants and groups, the MEG data were registered to an average head position and regional waveforms were obtained by calculating the local field power of the planar gradiometers. Diffusion tensor images obtained in the same individuals were preprocessed to provide FA maps for each participant. The MEG/FA data were then integrated using the jICA software (http://mialab.mrn.org/software/fit). We identified MEG/FA components that demonstrated significantly different (p<0.05) covariation in MEG/FA data between diagnostic groups (SP vs. HC) and three components that captured the predominant sensory responses in the MEG data. Lower FA values in bilateral posterior parietal regions, which include anterior/posterior association tracts, were associated with reduced MEG amplitude (120-170 ms) of the visual response in occipital sensors in SP relative to HC. Additionally, increased FA in a right medial frontal region was linked with larger amplitude late MEG activity (300-400 ms) in bilateral central channels for SP relative to HC. Step-wise linear regression provided evidence that right temporal, occipital and late central components were significant predictors of reaction time and cognitive performance based on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) cognitive assessment battery. These results point to dysfunction in a posterior visual processing network in schizophrenia, with reduced MEG amplitude, reduced FA and poorer overall performance on the MATRICS. Interestingly, the spatial location of the MEG activity and the associated FA regions are spatially consistent with white matter regions that subserve these brain areas. This novel approach provides evidence for significant pairing between function (neurophysiology) and structure (white matter integrity) and demonstrates that this multivariate, multimodal integration technique is sensitive to group differences in function and structure.
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Affiliation(s)
- J M Stephen
- The Mind Research Network and Lovelace Biomedical and Environmental Research Institute, 1101 Yale Blvd NE, Albuquerque, NM 87106, USA.
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Ellis MJ, Rutka JT, Kulkarni AV, Dirks PB, Widjaja E. Corticospinal tract mapping in children with ruptured arteriovenous malformations using functionally guided diffusion-tensor imaging. J Neurosurg Pediatr 2012; 9:505-10. [PMID: 22546028 DOI: 10.3171/2012.1.peds11363] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Arteriovenous malformations (AVMs) can lead to distortion or reorganization of functional brain anatomy, making localization of eloquent white matter tracts challenging. To improve the accuracy of corticospinal tract (CST) mapping, recent studies have examined the use of functional imaging techniques to help localize cortical motor activations and use these as seed points to reconstruct CSTs using diffusion-tensor imaging (DTI). The authors examined the role of pretreatment functionally guided DTI CST mapping in 3 children with ruptured AVMs. In 2 patients, magnetoencephalography motor activations were adjacent to the nidus and/or hemorrhagic cavity. However, in 1 child, functional MRI motor activations were detected in both hemispheres, suggestive of partial transfer of cortical motor function. In all children, quantitative analysis showed that fractional anisotropy values and fiber density indices were reduced in the CSTs of the hemisphere harboring the AVM compared with the unaffected side. In 2 children, CST caliber was slightly diminished, corresponding to no motor deficit in 1 patient and a temporary motor deficit in the other. In contrast, 1 child demonstrated marked reduction and displacement of the CSTs, correlating with severe motor deficit. Preoperative motor tractography data were loaded onto the intraoperative neuronavigation platform to guide complete resection of the AVM in 2 cases without permanent neurological deficits. These preliminary results confirm the feasibility of CST mapping in children with ruptured AVMs using functionally guided DTI tractography. Prospective studies are needed to assess the full value of this technique in the risk stratification, prognosis, and multimodality management of pediatric AVMs.
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Affiliation(s)
- Michael J Ellis
- Department of Neurosurgery, Hospital for Sick Children, Toronto, Ontario, Canada
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21
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Current world literature. Curr Opin Pediatr 2012; 24:134-44. [PMID: 22245849 DOI: 10.1097/mop.0b013e328350498a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dockstader C, Gaetz W, Rockel C, Mabbott DJ. White matter maturation in visual and motor areas predicts the latency of visual activation in children. Hum Brain Mapp 2011; 33:179-91. [PMID: 21432944 DOI: 10.1002/hbm.21203] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 08/31/2010] [Accepted: 10/20/2010] [Indexed: 11/09/2022] Open
Abstract
In humans, white matter maturation is important for the improvement of cognitive function and performance with age. Across studies the variables of white matter maturity and age are highly correlated; however, the unique contributions of white matter to information processing speed remain relatively unknown. We investigated the relations between the speed of the visually-evoked P100m response and the biophysical properties of white matter in 11 healthy children performing a simple, visually-cued finger movement. We found that: (1) the latency of the early, visually-evoked response was related to the integrity of white matter in both visual and motor association areas and (2) white matter maturation in these areas accounted for the variations in visual processing speed, independent of age. Our study is a novel investigation of spatial-temporal dynamics in the developing brain and provides evidence that white matter maturation accounts for age-related decreases in the speed of visual response. Developmental models of cortical specialization should incorporate the unique role of white matter maturation in mediating changes in performance during tasks involving visual processing.
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Affiliation(s)
- Colleen Dockstader
- The Hospital for Sick Children Psychology, 555 University Ave, Toronto, Ontario, Canada
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Abstract
Medically refractory focal epilepsy is potentially curable by surgery. This Review considers the application of recent advances in structural and functional brain imaging to increase the number of patients with epilepsy who are treated surgically, and to reduce the risk of complications arising from such intervention. Current optimal MRI of brain structure can identify previously undetectable lesions, with voxel-based and quantitative analyses further increasing the diagnostic yield. If MRI proves unremarkable, PET (with (18)F-fluorodeoxyglucose) and single-photon emission CT of ictal-interictal cerebral blood flow might identify the brain region that contains the epileptic focus. Magnetoencephalography plus simultaneous EEG and functional MRI can map the location of interictal epileptic discharges, thereby facilitating placement of intracranial recording electrodes to define the site of seizure onset. Functional MRI can also lateralize language and localize primary motor, somatosensory and language areas, and shows promise for predicting the effects of temporal lobe resection on memory. Tractography can visualize the main cerebral white matter tracts, thereby predicting and reducing surgery risk. Currently, displays of the optic radiation and pyramidal tracts are the most relevant for epilepsy surgery. Reliable integration of structural and functional data into surgical image-guidance systems is being pursued, and promises safer neurosurgery for epilepsy in the future.
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Affiliation(s)
- John S Duncan
- National Society for Epilepsy, Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, Queen Square, London, UK.
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