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Rogan M, Friend AT, Rossetti GM, Edden R, Mikkelsen M, Oliver SJ, Macdonald JH, Mullins PG. Hypoxia alters posterior cingulate cortex metabolism during a memory task: A 1H fMRS study. Neuroimage 2022; 260:119397. [PMID: 35752413 PMCID: PMC9513808 DOI: 10.1016/j.neuroimage.2022.119397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 06/16/2022] [Indexed: 11/16/2022] Open
Abstract
Environmental hypoxia (fraction of inspired oxygen (FIO2) ∼ 0.120) is known to trigger a global increase in cerebral blood flow (CBF). However, regionally, a heterogeneous response is reported, particularly within the posterior cingulate cortex (PCC) where decreased CBF is found after two hours of hypoxic exposure. Furthermore, hypoxia reverses task-evoked BOLD signals within the PCC, and other regions of the default mode network, suggesting a reversal of neurovascular coupling. An alternative explanation is that the neural architecture supporting cognitive tasks is reorganised. Therefore, to confirm if this previous result is neural or vascular in origin, a measure of neural activity that is not haemodynamic-dependant is required. To achieve this, we utilised functional magnetic resonance spectroscopy to probe the glutamate response to memory recall in the PCC during normoxia (FIO2 = 0.209) and after two hours of poikilocapnic hypoxia (FIO2 = 0.120). We also acquired ASL-based measures of CBF to confirm previous findings of reduced CBF within the PCC in hypoxia. Consistent with previous findings, hypoxia induced a reduction in CBF within the PCC and other regions of the default mode network. Under normoxic conditions, memory recall was associated with an 8% increase in PCC glutamate compared to rest (P = 0.019); a change which was not observed during hypoxia. However, exploratory analysis of other neurometabolites showed that PCC glucose was reduced during hypoxia compared to normoxia both at rest (P = 0.039) and during the task (P = 0.046). We conclude that hypoxia alters the activity-induced increase in glutamate, which may reflect a reduction in oxidative metabolism within the PCC. The reduction in glucose in hypoxia reflects continued metabolism, presumably by non-oxidative means, without replacement of glucose due to reduced CBF.
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Affiliation(s)
- Matthew Rogan
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom; The Bangor Imaging Unit, Bangor University, Bangor, United Kingdom; Institute for Applied Human Physiology, Bangor University, Bangor, United Kingdom
| | - Alexander T Friend
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom; Institute for Applied Human Physiology, Bangor University, Bangor, United Kingdom
| | - Gabriella Mk Rossetti
- Centre for Integrative Neuroscience and Neurodynamics, University of Reading, Reading, United Kingdom
| | - Richard Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Mark Mikkelsen
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Samuel J Oliver
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom; Institute for Applied Human Physiology, Bangor University, Bangor, United Kingdom
| | - Jamie H Macdonald
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom; Institute for Applied Human Physiology, Bangor University, Bangor, United Kingdom
| | - Paul G Mullins
- School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom; The Bangor Imaging Unit, Bangor University, Bangor, United Kingdom; Institute for Applied Human Physiology, Bangor University, Bangor, United Kingdom.
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Hui SCN, Mikkelsen M, Zöllner HJ, Ahluwalia V, Alcauter S, Baltusis L, Barany DA, Barlow LR, Becker R, Berman JI, Berrington A, Bhattacharyya PK, Blicher JU, Bogner W, Brown MS, Calhoun VD, Castillo R, Cecil KM, Choi YB, Chu WCW, Clarke WT, Craven AR, Cuypers K, Dacko M, de la Fuente-Sandoval C, Desmond P, Domagalik A, Dumont J, Duncan NW, Dydak U, Dyke K, Edmondson DA, Ende G, Ersland L, Evans CJ, Fermin ASR, Ferretti A, Fillmer A, Gong T, Greenhouse I, Grist JT, Gu M, Harris AD, Hat K, Heba S, Heckova E, Hegarty JP, Heise KF, Honda S, Jacobson A, Jansen JFA, Jenkins CW, Johnston SJ, Juchem C, Kangarlu A, Kerr AB, Landheer K, Lange T, Lee P, Levendovszky SR, Limperopoulos C, Liu F, Lloyd W, Lythgoe DJ, Machizawa MG, MacMillan EL, Maddock RJ, Manzhurtsev AV, Martinez-Gudino ML, Miller JJ, Mirzakhanian H, Moreno-Ortega M, Mullins PG, Nakajima S, Near J, Noeske R, Nordhøy W, Oeltzschner G, Osorio-Duran R, Otaduy MCG, Pasaye EH, Peeters R, Peltier SJ, Pilatus U, Polomac N, Porges EC, Pradhan S, Prisciandaro JJ, Puts NA, Rae CD, Reyes-Madrigal F, Roberts TPL, Robertson CE, Rosenberg JT, Rotaru DG, O'Gorman Tuura RL, Saleh MG, Sandberg K, Sangill R, Schembri K, Schrantee A, Semenova NA, Singel D, Sitnikov R, Smith J, Song Y, Stark C, Stoffers D, Swinnen SP, Tain R, Tanase C, Tapper S, Tegenthoff M, Thiel T, Thioux M, Truong P, van Dijk P, Vella N, Vidyasagar R, Vovk A, Wang G, Westlye LT, Wilbur TK, Willoughby WR, Wilson M, Wittsack HJ, Woods AJ, Wu YC, Xu J, Lopez MY, Yeung DKW, Zhao Q, Zhou X, Zupan G, Edden RAE. Frequency drift in MR spectroscopy at 3T. Neuroimage 2021; 241:118430. [PMID: 34314848 PMCID: PMC8456751 DOI: 10.1016/j.neuroimage.2021.118430] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/18/2021] [Accepted: 07/22/2021] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Heating of gradient coils and passive shim components is a common cause of instability in the B0 field, especially when gradient intensive sequences are used. The aim of the study was to set a benchmark for typical drift encountered during MR spectroscopy (MRS) to assess the need for real-time field-frequency locking on MRI scanners by comparing field drift data from a large number of sites. METHOD A standardized protocol was developed for 80 participating sites using 99 3T MR scanners from 3 major vendors. Phantom water signals were acquired before and after an EPI sequence. The protocol consisted of: minimal preparatory imaging; a short pre-fMRI PRESS; a ten-minute fMRI acquisition; and a long post-fMRI PRESS acquisition. Both pre- and post-fMRI PRESS were non-water suppressed. Real-time frequency stabilization/adjustment was switched off when appropriate. Sixty scanners repeated the protocol for a second dataset. In addition, a three-hour post-fMRI MRS acquisition was performed at one site to observe change of gradient temperature and drift rate. Spectral analysis was performed using MATLAB. Frequency drift in pre-fMRI PRESS data were compared with the first 5:20 minutes and the full 30:00 minutes of data after fMRI. Median (interquartile range) drifts were measured and showed in violin plot. Paired t-tests were performed to compare frequency drift pre- and post-fMRI. A simulated in vivo spectrum was generated using FID-A to visualize the effect of the observed frequency drifts. The simulated spectrum was convolved with the frequency trace for the most extreme cases. Impacts of frequency drifts on NAA and GABA were also simulated as a function of linear drift. Data from the repeated protocol were compared with the corresponding first dataset using Pearson's and intraclass correlation coefficients (ICC). RESULTS Of the data collected from 99 scanners, 4 were excluded due to various reasons. Thus, data from 95 scanners were ultimately analyzed. For the first 5:20 min (64 transients), median (interquartile range) drift was 0.44 (1.29) Hz before fMRI and 0.83 (1.29) Hz after. This increased to 3.15 (4.02) Hz for the full 30 min (360 transients) run. Average drift rates were 0.29 Hz/min before fMRI and 0.43 Hz/min after. Paired t-tests indicated that drift increased after fMRI, as expected (p < 0.05). Simulated spectra convolved with the frequency drift showed that the intensity of the NAA singlet was reduced by up to 26%, 44 % and 18% for GE, Philips and Siemens scanners after fMRI, respectively. ICCs indicated good agreement between datasets acquired on separate days. The single site long acquisition showed drift rate was reduced to 0.03 Hz/min approximately three hours after fMRI. DISCUSSION This study analyzed frequency drift data from 95 3T MRI scanners. Median levels of drift were relatively low (5-min average under 1 Hz), but the most extreme cases suffered from higher levels of drift. The extent of drift varied across scanners which both linear and nonlinear drifts were observed.
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Affiliation(s)
- Steve C N Hui
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Mark Mikkelsen
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Helge J Zöllner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Vishwadeep Ahluwalia
- GSU/GT Center for Advanced Brain Imaging, Georgia Institute of Technology, Atlanta, GA USA
| | - Sarael Alcauter
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, Mexico
| | - Laima Baltusis
- Center for Cognitive and Neurobiological Imaging, Stanford University, Stanford, CA USA
| | - Deborah A Barany
- Department of Kinesiology, University of Georgia, and Augusta University/University of Georgia Medical Partnership, Athens, GA USA
| | - Laura R Barlow
- Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada
| | - Robert Becker
- Center for Innovative Psychiatry and Psychotherapy Research, Department Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jeffrey I Berman
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA USA
| | - Adam Berrington
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | | | - Jakob Udby Blicher
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Wolfgang Bogner
- Department of Biomedical Imaging and Image-guided Therapy, High-Field MR Center, Medical University of Vienna, Vienna, Austria
| | - Mark S Brown
- Department of Radiology, Medical Physics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Vince D Calhoun
- Tri-Institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State University, Georgia Institute of Technology, and Emory University, Atlanta, GA USA
| | - Ryan Castillo
- NeuRA Imaging, Neuroscience Research Australia, Randwick, Australia
| | - Kim M Cecil
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH USA
| | - Yeo Bi Choi
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH USA
| | - Winnie C W Chu
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, China
| | - William T Clarke
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Alexander R Craven
- Department of Biological and Medical Psychology, University of Bergen, Haukeland University Hospital, Bergen, Norway
| | - Koen Cuypers
- REVAL Rehabilitation Research Institute (REVAL), Hasselt University, Diepenbeek, Belgium; Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Michael Dacko
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Camilo de la Fuente-Sandoval
- Laboratory of Experimental Psychiatry & Neuropsychiatry Department, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico
| | - Patricia Desmond
- Department of Radiology, University of Melbourne/ Royal Melbourne Hospital, Melbourne, Australia
| | - Aleksandra Domagalik
- Brain Imaging Core Facility, Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Julien Dumont
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France
| | - Niall W Duncan
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN USA
| | - Katherine Dyke
- School of Psychology, University of Nottingham, Nottingham, UK
| | - David A Edmondson
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH USA
| | - Gabriele Ende
- Center for Innovative Psychiatry and Psychotherapy Research, Department Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Lars Ersland
- Department of Clinical Engineering, University of Bergen, Haukeland University Hospital, Bergen, Norway
| | | | - Alan S R Fermin
- Center for Brain, Mind and KANSEI Sciences Research, Hiroshima University, Hiroshima, Japan
| | - Antonio Ferretti
- Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Ariane Fillmer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, Germany
| | - Tao Gong
- Department of Imaging and Nuclear Medicine, Shandong Medical Imaging Research Institute, Shandong University, Jinan, China
| | - Ian Greenhouse
- Department of Human Physiology, University of Oregon, Eugene, OR USA
| | - James T Grist
- Department of Physiology, Anatomy, and Genetics, Oxford Centre for Magnetic Resonance / Department of Radiology, The Churchill Hospital, The University of Oxford, Oxford, UK
| | - Meng Gu
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Ashley D Harris
- Department of Radiology, University of Calgary, Calgary, Canada
| | - Katarzyna Hat
- Consciousness Lab, Institute of Psychology, Jagiellonian University, Kraków, Poland
| | - Stefanie Heba
- Department of Neurology, BG University Hospital Bergmannsheil, Bochum, Germany
| | - Eva Heckova
- Department of Biomedical Imaging and Image-guided Therapy, High-Field MR Center, Medical University of Vienna, Vienna, Austria
| | - John P Hegarty
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA
| | | | - Shiori Honda
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Aaron Jacobson
- Department of Radiology / Psychiatry, University of California San Diego, San Diego, CA USA
| | - Jacobus F A Jansen
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Stephen J Johnston
- Psychology Department / Clinical Imaging Facility, Swansea University, Swansea, UK
| | - Christoph Juchem
- Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY USA
| | - Alayar Kangarlu
- Department of Psychiatry, Columbia University Irving Medical Center/New York State Psychiatric Institute, New York, NY USA
| | - Adam B Kerr
- Center for Cognitive and Neurobiological Imaging, Stanford University, Stanford, CA USA
| | - Karl Landheer
- Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY USA
| | - Thomas Lange
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Phil Lee
- Department of Radiology / Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, KS USA
| | | | - Catherine Limperopoulos
- Developing Brain Institute, Diagnostic Imaging and Radiology, Children's National Hospital, Washington, DC USA
| | - Feng Liu
- Department of Psychiatry, Columbia University Irving Medical Center/New York State Psychiatric Institute, New York, NY USA
| | - William Lloyd
- Division of Informatics, Imaging & Data Sciences, University of Manchester, Manchester, UK
| | - David J Lythgoe
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Maro G Machizawa
- Center for Brain, Mind and KANSEI Sciences Research, Hiroshima University, Hiroshima, Japan
| | - Erin L MacMillan
- Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada; Philips Canada, Markham, ON, Canada
| | - Richard J Maddock
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Imaging Research Center, Davis, CA USA
| | - Andrei V Manzhurtsev
- Department of Radiology, Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russia; Emanuel Institute of Biochemical Physics of the Russian Academy of Sciences, Moscow, Russia
| | - María L Martinez-Gudino
- Departamento de Imágenes Cerebrales, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Jack J Miller
- Department of Physics, University of Oxford, Oxford, UK; The MR Research Centre & The PET Research Centre, Aarhus University, Aarhus, DK
| | - Heline Mirzakhanian
- Department of Radiology / Psychiatry, University of California San Diego, San Diego, CA USA
| | - Marta Moreno-Ortega
- Department of Psychiatry, Columbia University Irving Medical Center/New York State Psychiatric Institute, New York, NY USA
| | - Paul G Mullins
- Bangor Imaging Unit, Department of Psychology, Bangor University, Bangor, Wales, UK
| | - Shinichiro Nakajima
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Jamie Near
- Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada
| | | | - Wibeke Nordhøy
- NORMENT, Division of Mental Health and Addiction and Department of Diagnostic Physics, Division of Radiology and Nuclear Medicine, Oslo University Hospital / Department of Psychology, University of Oslo, Oslo, Norway
| | - Georg Oeltzschner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Raul Osorio-Duran
- Departamento de Imágenes Cerebrales, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Maria C G Otaduy
- LIM44, Instituto e Departamento de Radiologia, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Erick H Pasaye
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, Mexico
| | - Ronald Peeters
- Department of Imaging & Pathology, Department of Radiology, University Hospitals Leuven, KU Leuven, Leuven, Belgium
| | - Scott J Peltier
- Functional MRI Laboratory, University of Michigan, Ann Arbor, MI USA
| | - Ulrich Pilatus
- Institute of Neuroradiology, Goethe-University Frankfurt, Frankfurt, Germany
| | - Nenad Polomac
- Institute of Neuroradiology, Goethe-University Frankfurt, Frankfurt, Germany
| | - Eric C Porges
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, College of Public Health and Health Professions. Department of Neuroscience, College of Medicine, University of Florida, Gainesville, USA
| | - Subechhya Pradhan
- Developing Brain Institute, Diagnostic Imaging and Radiology, Children's National Hospital, Washington, DC USA
| | - James Joseph Prisciandaro
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC USA
| | - Nicolaas A Puts
- Department of Forensic & Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, King's College London, London, UK
| | - Caroline D Rae
- NeuRA Imaging, Neuroscience Research Australia, Randwick, Australia
| | - Francisco Reyes-Madrigal
- Laboratory of Experimental Psychiatry & Neuropsychiatry Department, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico
| | - Timothy P L Roberts
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA USA
| | - Caroline E Robertson
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH USA
| | - Jens T Rosenberg
- McKnight Brain Institute, AMRIS, University of Florida, Gainesville, FL USA
| | - Diana-Georgiana Rotaru
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Ruth L O'Gorman Tuura
- Center for MR Research, University Children's Hospital, Zurich, University of Zurich, Switzerland
| | - Muhammad G Saleh
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, USA
| | - Kristian Sandberg
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Ryan Sangill
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | | | - Anouk Schrantee
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Natalia A Semenova
- Department of Radiology, Clinical and Research Institute of Emergency Pediatric Surgery and Trauma, Moscow, Russia; Emanuel Institute of Biochemical Physics of the Russian Academy of Sciences, Moscow, Russia
| | - Debra Singel
- Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Rouslan Sitnikov
- Clinical Neuroscience, MRI Centre, Karolinska Institute, Stockholm, Sweden
| | - Jolinda Smith
- Lewis Center for Neuroimaging, University of Oregon, Eugene, OR USA
| | - Yulu Song
- Department of Imaging and Nuclear Medicine, Shandong Medical Imaging Research Institute, Shandong University, Jinan, China
| | - Craig Stark
- Department of Neurobiology and Behavior, Facility for Imaging and Brain Research (FIBRE) & Campus Center for Neuroimaging (CCNI), School of Biological Sciences, University of California, Irvine, Irvine, CA USA
| | - Diederick Stoffers
- Spinoza Centre for Neuroimaging, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | | | - Rongwen Tain
- Department of Neurobiology and Behavior, Facility for Imaging and Brain Research (FIBRE) & Campus Center for Neuroimaging (CCNI), School of Biological Sciences, University of California, Irvine, Irvine, CA USA
| | - Costin Tanase
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Imaging Research Center, Davis, CA USA
| | - Sofie Tapper
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Martin Tegenthoff
- Department of Neurology, BG University Hospital Bergmannsheil, Bochum, Germany
| | - Thomas Thiel
- Institute of Clinical Neuroscience and Medical Psychology, University Dusseldorf, Medical Faculty, Düsseldorf, Germany
| | - Marc Thioux
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter Truong
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada
| | - Pim van Dijk
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nolan Vella
- Medical Physics, Mater Dei Hospital, Imsida, Malta
| | - Rishma Vidyasagar
- Melbourne Dementia Research Centre, Florey Institute of Neurosciences and Mental Health, Melbourne, Australia
| | - Andrej Vovk
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Guangbin Wang
- Department of Imaging and Nuclear Medicine, Shandong Medical Imaging Research Institute, Shandong University, Jinan, China
| | - Lars T Westlye
- NORMENT, Division of Mental Health and Addiction and Department of Diagnostic Physics, Division of Radiology and Nuclear Medicine, Oslo University Hospital / Department of Psychology, University of Oslo, Oslo, Norway
| | - Timothy K Wilbur
- Department of Radiology, University of Washington, Seattle, WA USA
| | - William R Willoughby
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL USA
| | - Martin Wilson
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham, UK
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, Düsseldorf, Germany
| | - Adam J Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, College of Public Health and Health Professions. Department of Neuroscience, College of Medicine, University of Florida, Gainesville, USA
| | - Yen-Chien Wu
- Department of Radiology, TMU-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Junqian Xu
- Department of Radiology and Psychiatry, Baylor College of Medicine, Houston, USA
| | | | - David K W Yeung
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong, China
| | - Qun Zhao
- Bioimaging Research Center, Department of Physics and Astronomy, University of Georgia, Athens, GA USA
| | - Xiaopeng Zhou
- School of Health Sciences, Purdue University, West Lafayette, IN USA
| | - Gasper Zupan
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
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Friend AT, Rogan M, Rossetti GMK, Lawley JS, Mullins PG, Sandoo A, Macdonald JH, Oliver SJ. Bilateral regional extracranial blood flow regulation to hypoxia and unilateral duplex ultrasound measurement error. Exp Physiol 2021; 106:1535-1548. [PMID: 33866627 DOI: 10.1113/ep089196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/14/2021] [Indexed: 02/05/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is blood flow regulation to hypoxia different between the internal carotid arteries (ICAs) and vertebral arteries (VAs), and what is the measurement error in unilateral extracranial artery assessments compared to bilateral? What is the main finding and its importance? ICA and VA blood flow regulation to hypoxia is comparable when factoring for vessel type and vessel side. Compared to bilateral assessment, vessels assessed unilaterally had individual measurement errors of up to 37%. Assessing the vessel with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error. ABSTRACT Whether blood flow regulation to hypoxia is similar between left and right internal carotid arteries (ICAs) and vertebral arteries (VAs) is unclear. Extracranial blood flow is regularly calculated by doubling a unilateral assessment; however, lateral artery differences may lead to measurement error. This study aimed to determine extracranial blood flow regulation to hypoxia when factoring for vessel type (ICAs or VAs) and vessel side (left or right) effects, and to investigate unilateral assessment measurement error compared to bilateral assessment. In a repeated-measures crossover design, extracranial arteries of 44 participants were assessed bilaterally by duplex ultrasound during 90 min of normoxic and poikilocapnic hypoxic (12.0% fraction of inspired oxygen) conditions. Linear mixed model analyses revealed no Condition × Vessel Type × Vessel Side interaction for blood flow, vessel diameter and flow velocity (all P > 0.05) indicating left and right ICA and VA blood flow regulation to hypoxia was similar. Bilateral hypoxic reactivity was comparable (ICAs, 1.4 (1.0) vs. VAs, 1.7 (1.1) Δ%·Δ S p O 2 -1 ; P = 0.12). Compared to bilateral assessment, unilateral mean measurement error of the relative blood flow response to hypoxia was up to 5%, but individual errors reached 37% and were greatest in ICAs and VAs with the smaller resting blood flow due to a ratio-scaling problem. In conclusion, left and right ICA and VA regulation to hypoxia is comparable when factoring for vessel type and vessel side. Assessing the ICA and VA vessels with the larger resting blood flow, not the left or right vessel, reduces unilateral measurement error.
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Affiliation(s)
- Alexander T Friend
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Matthew Rogan
- Bangor Imaging Unit, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Gabriella M K Rossetti
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK.,Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | - Justin S Lawley
- Department of Sport Science, Division of Physiology, University of Innsbruck, Innsbruck, Austria
| | - Paul G Mullins
- Bangor Imaging Unit, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Aamer Sandoo
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
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Lin A, Andronesi O, Bogner W, Choi I, Coello E, Cudalbu C, Juchem C, Kemp GJ, Kreis R, Krššák M, Lee P, Maudsley AA, Meyerspeer M, Mlynarik V, Near J, Öz G, Peek AL, Puts NA, Ratai E, Tkáč I, Mullins PG. Minimum Reporting Standards for in vivo Magnetic Resonance Spectroscopy (MRSinMRS): Experts' consensus recommendations. NMR Biomed 2021; 34:e4484. [PMID: 33559967 PMCID: PMC8647919 DOI: 10.1002/nbm.4484] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 11/24/2020] [Accepted: 01/12/2021] [Indexed: 05/08/2023]
Abstract
The translation of MRS to clinical practice has been impeded by the lack of technical standardization. There are multiple methods of acquisition, post-processing, and analysis whose details greatly impact the interpretation of the results. These details are often not fully reported, making it difficult to assess MRS studies on a standardized basis. This hampers the reviewing of manuscripts, limits the reproducibility of study results, and complicates meta-analysis of the literature. In this paper a consensus group of MRS experts provides minimum guidelines for the reporting of MRS methods and results, including the standardized description of MRS hardware, data acquisition, analysis, and quality assessment. This consensus statement describes each of these requirements in detail and includes a checklist to assist authors and journal reviewers and to provide a practical way for journal editors to ensure that MRS studies are reported in full.
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Affiliation(s)
- Alexander Lin
- Center for Clinical Spectroscopy, Department of Radiology, Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Ovidiu Andronesi
- Department of RadiologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
| | - In‐Young Choi
- Department of Neurology, Hoglund Biomedical Imaging CenterUniversity of Kansas Medical CenterKansas CityKansasUSA
| | - Eduardo Coello
- Center for Clinical Spectroscopy, Department of Radiology, Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Cristina Cudalbu
- Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Christoph Juchem
- Departments of Biomedical Engineering and RadiologyColumbia UniversityNew YorkNew YorkUSA
| | - Graham J. Kemp
- Department of Musculoskeletal and Ageing Science and Liverpool Magnetic Resonance Imaging Centre (LiMRIC)University of LiverpoolLiverpoolUK
| | - Roland Kreis
- Departments of Radiology and Biomedical ResearchUniversity of BernBernSwitzerland
| | - Martin Krššák
- Department of Medicine III and Department of Biomedical Imaging and Image guided TherapyMedical University of ViennaViennaAustria
| | - Phil Lee
- Department of Radiology, Hoglund Biomedical Imaging CenterUniversity of Kansas Medical CenterKansas CityKansasUSA
| | | | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Vladamir Mlynarik
- Magnetic Resonance Centre of Excellence. Medical University of ViennaViennaAustria
| | - Jamie Near
- Brain Imaging Centre, Douglas Research Centre, Department of PsychiatryMcGill UniversityMontrealQuebecCanada
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of RadiologyUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Aimie L. Peek
- Faculty of Health SciencesUniversity of SydneySydneyAustralia
| | - Nicolaas A. Puts
- Department of Forensic and Neurodevelopmental SciencesSackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology, and Neuroscience, King's College LondonLondonUK
| | - Eva‐Maria Ratai
- A.A. Martinos Center for Biomedical Imaging, Neuroradiology Division, Department of RadiologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Ivan Tkáč
- Faculty of Health SciencesUniversity of SydneySydneyAustralia
| | - Paul G. Mullins
- Bangor Imaging Unit, School of PsychologyBangor UniversityBangorGwyneddUK
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5
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Rossetti GM, d'Avossa G, Rogan M, Macdonald JH, Oliver SJ, Mullins PG. Reversal of neurovascular coupling in the default mode network: Evidence from hypoxia. J Cereb Blood Flow Metab 2021; 41:805-818. [PMID: 32538282 PMCID: PMC7983511 DOI: 10.1177/0271678x20930827] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Local changes in cerebral blood flow are thought to match changes in neuronal activity, a phenomenon termed neurovascular coupling. Hypoxia increases global resting cerebral blood flow, but regional cerebral blood flow (rCBF) changes are non-uniform. Hypoxia decreases baseline rCBF to the default mode network (DMN), which could reflect either decreased neuronal activity or altered neurovascular coupling. To distinguish between these hypotheses, we characterized the effects of hypoxia on baseline rCBF, task performance, and the hemodynamic (BOLD) response to task activity. During hypoxia, baseline CBF increased across most of the brain, but decreased in DMN regions. Performance on memory recall and motion detection tasks was not diminished, suggesting task-relevant neuronal activity was unaffected. Hypoxia reversed both positive and negative task-evoked BOLD responses in the DMN, suggesting hypoxia reverses neurovascular coupling in the DMN of healthy adults. The reversal of the BOLD response was specific to the DMN. Hypoxia produced modest increases in activations in the visual attention network (VAN) during the motion detection task, and had no effect on activations in the visual cortex during visual stimulation. This regional specificity may be particularly pertinent to clinical populations characterized by hypoxemia and may enhance understanding of regional specificity in neurodegenerative disease pathology.
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Affiliation(s)
- Gabriella Mk Rossetti
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Giovanni d'Avossa
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Matthew Rogan
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Paul G Mullins
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
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6
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Weidacker K, Johnston SJ, Mullins PG, Boy F, Dymond S. Neurochemistry of response inhibition and interference in gambling disorder: a preliminary study of γ-aminobutyric acid (GABA+) and glutamate-glutamine (Glx). CNS Spectr 2021:1-11. [PMID: 33752778 DOI: 10.1017/s1092852921000316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Neurobehavioral research on the role of impulsivity in gambling disorder (GD) has produced heterogeneous findings. Impulsivity is multifaceted with different experimental tasks measuring different subprocesses, such as response inhibition and distractor interference. Little is known about the neurochemistry of inhibition and interference in GD. METHODS We investigated inhibition with the stop signal task (SST) and interference with the Eriksen Flanker task, and related performance to metabolite levels in individuals with and without GD. We employed magnetic resonance spectroscopy (MRS) to record glutamate-glutamine (Glx/Cr) and inhibitory, γ-aminobutyric acid (GABA+/Cr) levels in the dorsal ACC (dACC), right dorsolateral prefrontal cortex (dlPFC), and an occipital control voxel. RESULTS We found slower processing of complex stimuli in the Flanker task in GD (P < .001, η2p = 0.78), and no group differences in SST performance. Levels of dACC Glx/Cr and frequency of incongruent errors were correlated positively in GD only (r = 0.92, P = .001). Larger positive correlations were found for those with GD between dACC GABA+/Cr and SST Go error response times (z = 2.83, P = .004), as well as between dACC Glx/Cr and frequency of Go errors (z = 2.23, P = .03), indicating general Glx-related error processing deficits. Both groups expressed equivalent positive correlations between posterror slowing and Glx/Cr in the right dlPFC (GD: r = 0.74, P = .02; non-GD: r = .71, P = .01). CONCLUSION Inhibition and interference impairments are reflected in dACC baseline metabolite levels and error processing deficits in GD.
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Affiliation(s)
| | | | - Paul G Mullins
- School of Psychology, Bangor University, Bangor, United Kingdom
| | - Frederic Boy
- School of Psychology, Swansea University, Swansea, United Kingdom
- School of Management, Swansea University, Swansea, United Kingdom
| | - Simon Dymond
- School of Psychology, Swansea University, Swansea, United Kingdom
- Department of Psychology, Reykjavík University, Reykjavík, Iceland
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7
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Weidacker K, Johnston SJ, Mullins PG, Boy F, Dymond S. Impulsive decision-making and gambling severity: The influence of γ-amino-butyric acid (GABA) and glutamate-glutamine (Glx). Eur Neuropsychopharmacol 2020; 32:36-46. [PMID: 31901336 DOI: 10.1016/j.euroneuro.2019.12.110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 11/15/2019] [Accepted: 12/13/2019] [Indexed: 11/28/2022]
Abstract
Discounting larger, delayed rewards for smaller, immediate rewards is a stable psychological trait known to be impaired in gambling disorder (GD). Neuroimaging with non-GD populations indicates involvement of anterior cingulate (ACC) and dorsolateral prefrontal cortex (dlPFC) in delay discounting. However, little is known about the role of intrinsic properties of brain functioning, such as neurotransmitter action, in impaired discounting in GD. Here, we used magnetic resonance spectroscopy to assess glutamate-glutamine (Glx) and γ-amino-butyric acid (GABA+) concentrations in the dorsal ACC (dACC), dlPFC and occipital cortex of human males with and without GD. Gambling symptom severity correlated negatively with Glx levels in the dACC and occipital voxels. Discounting of small and medium delayed rewards was negatively associated with GABA+ in the dACC, while the discounting of large delayed rewards was negatively associated with GABA+/Glx ratios in the dlPFC. Additionally, in GD, discounting of large delayed rewards was negatively correlated with occipital GABA+ levels. Overall, these findings show that high gambling symptom severity is associated with low levels of Glx and that dACC (GABA+), right dlPFC (GABA+/Glx), and occipital areas (GABA+) track the magnitude of delayed rewards during discounting.
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Affiliation(s)
- Kathrin Weidacker
- Department of Psychology, Swansea University, Singleton Campus, Swansea SA2 8PP, United Kingdom; Department of Psychiatry, University of Cambridge, Box 189, Level E4, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Stephen J Johnston
- Department of Psychology, Swansea University, Singleton Campus, Swansea SA2 8PP, United Kingdom
| | - Paul G Mullins
- School of Psychology, Bangor University, Bangor, Gwynedd LL57 2AS, United Kingdom
| | - Fred Boy
- Department of Psychology, Swansea University, Singleton Campus, Swansea SA2 8PP, United Kingdom; School of Management, Swansea University, Bay Campus, Swansea SA1 8EN, United Kingdom
| | - Simon Dymond
- Department of Psychology, Swansea University, Singleton Campus, Swansea SA2 8PP, United Kingdom; Department of Psychology, Reykjavík University, Menntavegur 1, Nauthólsvík, 101 Reykjavík, Iceland.
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8
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Wilson M, Andronesi O, Barker PB, Bartha R, Bizzi A, Bolan PJ, Brindle KM, Choi IY, Cudalbu C, Dydak U, Emir UE, Gonzalez RG, Gruber S, Gruetter R, Gupta RK, Heerschap A, Henning A, Hetherington HP, Huppi PS, Hurd RE, Kantarci K, Kauppinen RA, Klomp DWJ, Kreis R, Kruiskamp MJ, Leach MO, Lin AP, Luijten PR, Marjańska M, Maudsley AA, Meyerhoff DJ, Mountford CE, Mullins PG, Murdoch JB, Nelson SJ, Noeske R, Öz G, Pan JW, Peet AC, Poptani H, Posse S, Ratai EM, Salibi N, Scheenen TWJ, Smith ICP, Soher BJ, Tkáč I, Vigneron DB, Howe FA. Methodological consensus on clinical proton MRS of the brain: Review and recommendations. Magn Reson Med 2019; 82:527-550. [PMID: 30919510 PMCID: PMC7179569 DOI: 10.1002/mrm.27742] [Citation(s) in RCA: 229] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/01/2019] [Accepted: 02/25/2019] [Indexed: 12/14/2022]
Abstract
Proton MRS (1 H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi-adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0 ) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use.
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Affiliation(s)
- Martin Wilson
- Centre for Human Brain Health and School of Psychology, University of Birmingham, Birmingham, England
| | - Ovidiu Andronesi
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Peter B Barker
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Robert Bartha
- Robarts Research Institute, University of Western Ontario, London, Canada
| | - Alberto Bizzi
- U.O. Neuroradiologia, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Patrick J Bolan
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Kevin M Brindle
- Department of Biochemistry, University of Cambridge, Cambridge, England
| | - In-Young Choi
- Department of Neurology, Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas
| | - Cristina Cudalbu
- Center for Biomedical Imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, Indiana
| | - Uzay E Emir
- School of Health Sciences, Purdue University, West Lafayette, Indiana
| | - Ramon G Gonzalez
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Stephan Gruber
- High Field MR Center, Department of Biomedical imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, Center for Biomedical Imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Rakesh K Gupta
- Fortis Memorial Research Institute, Gurugram, Haryana, India
| | - Arend Heerschap
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anke Henning
- Max Planck Institute for Biological Cybernetics, Tuebingen, Germany
| | | | - Petra S Huppi
- Department of Pediatrics, University of Geneva, Geneva, Switzerland
| | - Ralph E Hurd
- Stanford Radiological Sciences Lab, Stanford, California
| | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Risto A Kauppinen
- School of Psychological Science, University of Bristol, Bristol, England
| | | | - Roland Kreis
- Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland
| | | | - Martin O Leach
- CRUK Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, London, England
| | - Alexander P Lin
- Center for Clinical Spectroscopy, Brigham and Women's Hospital, Harvard University Medical School, Boston, Massachusetts
| | | | - Małgorzata Marjańska
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | | | - Dieter J Meyerhoff
- DVA Medical Center and Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California
| | | | - Paul G Mullins
- Bangor Imaging Unit, School of Psychology, Bangor University, Bangor, Wales
| | | | - Sarah J Nelson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California
| | | | - Gülin Öz
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Julie W Pan
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Andrew C Peet
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, England
| | - Harish Poptani
- Centre for Preclinical Imaging, Institute of Translational Medicine, University of Liverpool, Liverpool, England
| | - Stefan Posse
- Department of Neurology, University of New Mexico, Albuquerque, New Mexico
| | - Eva-Maria Ratai
- Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Nouha Salibi
- MR R&D, Siemens Healthineers, Malvern, Pennsylvania
| | - Tom W J Scheenen
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Brian J Soher
- Department of Radiology, Duke University Medical Center, Durham, North Carolina
| | - Ivan Tkáč
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California
| | - Franklyn A Howe
- Molecular and Clinical Sciences, St George's University of London, London, England
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9
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Mullins PG. Towards a theory of functional magnetic resonance spectroscopy (fMRS): A meta-analysis and discussion of using MRS to measure changes in neurotransmitters in real time. Scand J Psychol 2018; 59:91-103. [PMID: 29356002 DOI: 10.1111/sjop.12411] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/01/2017] [Indexed: 02/06/2023]
Abstract
Proton magnetic resonance spectroscopy is a powerful tool to investigate neurochemistry and physiology in vivo. Recently researchers have started to use MRS to measure neurotransmitter changes related to neural activity, so called functional MRS (fMRS). Particular interest has been placed on measuring glutamate changes associated with neural function, but differences are reported in the size of changes seen. This review discusses fMRS, and includes meta-analyses of the relative size of glutamate changes seen in fMRS, and the impact experimental design and stimulus paradigm may have. On average glutamate was found to increase by 6.97% (±1.739%) in response to neural activation. However, factors of experimental design may have a large impact on the size of these changes. For example an increase of 4.749% (±1.45%) is seen in block studies compared to an increase of 13.429% (±3.59) in studies using event related paradigms. The stimulus being investigated also seems to play a role with prolonged visual stimuli showing a small mean increase in glutamate of 2.318% (±1.227%) while at the other extreme, pain stimuli show a mean stimulation effect of 14.458% (±3.736%). These differences are discussed with regards to possible physiologic interpretations, as well experimental design implications.
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10
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Gasparovic C, Chen H, Mullins PG. Errors in 1 H-MRS estimates of brain metabolite concentrations caused by failing to take into account tissue-specific signal relaxation. NMR Biomed 2018; 31:e3914. [PMID: 29727496 DOI: 10.1002/nbm.3914] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 06/08/2023]
Abstract
Accurate measurement of brain metabolite concentrations with proton magnetic resonance spectroscopy (1 H-MRS) can be problematic because of large voxels with mixed tissue composition, requiring adjustment for differing relaxation rates in each tissue if absolute concentration estimates are desired. Adjusting for tissue-specific metabolite signal relaxation, however, also requires a knowledge of the relative concentrations of the metabolite in gray (GM) and white (WM) matter, which are not known a priori. Expressions for the estimation of the molality and molarity of brain metabolites with 1 H-MRS are extended to account for tissue-specific relaxation of the metabolite signals and examined under different assumptions with simulated and real data. Although the modified equations have two unknowns, and hence are unsolvable explicitly, they are nonetheless useful for the estimation of the effect of tissue-specific metabolite relaxation rates on concentration estimates under a range of assumptions and experimental parameters using simulated and real data. In simulated data using reported GM and WM T1 and T2 times for N-acetylaspartate (NAA) at 3 T and a hypothetical GM/WM NAA ratio, errors of 6.5-7.8% in concentrations resulted when TR = 1.5 s and TE = 0.144 s, but were reduced to less than 0.5% when TR = 6 s and TE = 0.006 s. In real data obtained at TR/TE = 1.5 s/0.04 s, the difference in the results (4%) was similar to that obtained with simulated data when assuming tissue-specific relaxation times rather than GM-WM-averaged times. Using the expressions introduced in this article, these results can be extrapolated to any metabolite or set of assumptions regarding tissue-specific relaxation. Furthermore, although serving to bound the problem, this work underscores the challenge of correcting for relaxation effects, given that relaxation times are generally not known and impractical to measure in most studies. To minimize such effects, the data should be acquired with pulse sequence parameters that minimize the effect of signal relaxation.
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Affiliation(s)
| | - Hongji Chen
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Catonsville, MD, USA
| | - Paul G Mullins
- School of Psychology, Bangor University, Bangor, Gwynedd, UK
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11
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Jelen LA, King S, Mullins PG, Stone JM. Beyond static measures: A review of functional magnetic resonance spectroscopy and its potential to investigate dynamic glutamatergic abnormalities in schizophrenia. J Psychopharmacol 2018; 32:497-508. [PMID: 29368979 DOI: 10.1177/0269881117747579] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abnormalities of the glutamate system are increasingly implicated in schizophrenia but their exact nature remains unknown. Proton magnetic resonance spectroscopy (1H-MRS), while fundamental in revealing glutamatergic alterations in schizophrenia, has, until recently, been significantly limited and thought to only provide static measures. Functional magnetic resonance spectroscopy (fMRS), which uses sequential scans for dynamic measurement of a range of brain metabolites in activated brain areas, has lately been applied to a variety of task or stimulus conditions, producing interesting insights into neurometabolite responses to neural activation. Here, we summarise the existing 1H-MRS studies of brain glutamate in schizophrenia. We then present a comprehensive review of research studies that have utilised fMRS, and lastly consider how fMRS methods might further the understanding of glutamatergic abnormalities in schizophrenia.
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Affiliation(s)
- Luke A Jelen
- 1 The Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.,2 South London and Maudsley NHS Foundation Trust, UK
| | - Sinead King
- 1 The Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK
| | - Paul G Mullins
- 3 Bangor Imaging Unit, School of Psychology, Bangor University, Gwynedd, UK
| | - James M Stone
- 1 The Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK
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12
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Sibilia F, Kehoe E, Farrell D, Kerskens C, O'Neill D, McNulty J, Mullins PG, Bokde AL. [P3–346]: AGING‐RELATED MICROSTRUCTURAL ALTERATIONS ALONG THE LENGTH OF THE CINGULUM BUNDLE. Alzheimers Dement 2017. [DOI: 10.1016/j.jalz.2017.06.1561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | | | | | | | - Desmond O'Neill
- Trinity College DublinDublinIreland
- Trinity Centre for Health SciencesTallaght HospitalDublinIreland
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Lawley JS, Macdonald JH, Oliver SJ, Mullins PG. Unexpected reductions in regional cerebral perfusion during prolonged hypoxia. J Physiol 2016; 595:935-947. [PMID: 27506309 DOI: 10.1113/jp272557] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/04/2016] [Indexed: 01/06/2023] Open
Abstract
KEY POINTS Cognitive performance is impaired by hypoxia despite global cerebral oxygen delivery and metabolism being maintained. Using arterial spin labelled (ASL) magnetic resonance imaging, this is the first study to show regional reductions in cerebral blood flow (CBF) in response to decreased oxygen supply (hypoxia) at 2 h that increased in area and became more pronounced at 10 h. Reductions in CBF were seen in brain regions typically associated with the 'default mode' or 'task negative' network. Regional reductions in CBF, and associated vasoconstriction, within the default mode network in hypoxia is supported by increased vasodilatation in these regions to a subsequent hypercapnic (5% CO2 ) challenge. These results suggest an anatomical mechanism through which hypoxia may cause previously reported deficits in cognitive performance. ABSTRACT Hypoxia causes an increase in global cerebral blood flow, which maintains global cerebral oxygen delivery and metabolism. However, neurological deficits are abundant under hypoxic conditions. We investigated regional cerebral microvascular responses to acute (2 h) and prolonged (10 h) poikilocapnic normobaric hypoxia. We found that 2 h of hypoxia caused an expected increase in frontal cortical grey matter perfusion but unexpected perfusion decreases in regions of the brain normally associated with the 'default mode' or 'task negative' network. After 10 h in hypoxia, decreased blood flow to the major nodes of the default mode network became more pronounced and widespread. The use of a hypercapnic challenge (5% CO2 ) confirmed that these reductions in cerebral blood flow from hypoxia were related to vasoconstriction. Our findings demonstrate steady-state deactivation of the default network under acute hypoxia, which become more pronounced over time. Moreover, these data provide a unique insight into the nuanced localized cerebrovascular response to hypoxia that is not attainable through traditional methods. The observation of reduced perfusion in the posterior cingulate and cuneal cortex, which are regions assumed to play a role in declarative and procedural memory, provides an anatomical mechanism through which hypoxia may cause deficits in working memory.
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Affiliation(s)
- Justin S Lawley
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK.,Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX, USA
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK
| | - Paul G Mullins
- Bangor Imaging Centre, School of Psychology, Bangor University, Gwynedd, UK
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Ciblis AS, Butler ML, Quinn C, Clare L, Bokde ALW, Mullins PG, McNulty JP. Current Practice in the Referral of Individuals with Suspected Dementia for Neuroimaging by General Practitioners in Ireland and Wales. PLoS One 2016; 11:e0151793. [PMID: 27007435 PMCID: PMC4805299 DOI: 10.1371/journal.pone.0151793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 02/17/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES While early diagnosis of dementia is important, the question arises whether general practitioners (GPs) should engage in direct referrals. The current study investigated current referral practices for neuroimaging in dementia, access to imaging modalities and investigated related GP training in Ireland and North Wales. METHODS A questionnaire was distributed to GPs in the programme regions which included approximately two thirds of all GPs in the Republic of Ireland and all general practitioners in North Wales. A total of 2,093 questionnaires were issued. RESULTS 48.6% of Irish respondents and 24.3% of Welsh respondents directly referred patients with suspected dementia for neuroimaging. Irish GPs reported greater direct access to neuroimaging than their Welsh counterparts. A very small percentage of Irish and Welsh GPs (4.7% and 10% respectively) had received training in neuroimaging and the majority who referred patients for neuroimaging were not aware of any dementia-specific protocols for referrals (93.1% and 95% respectively). CONCLUSIONS The benefits of direct GP access to neuroimaging investigations for dementia have yet to be established. Our findings suggest that current GP speciality training in Ireland and Wales is deficient in dementia-specific and neuroimaging training with the concern being that inadequate training will lead to inadequate referrals. Further training would complement guidelines and provide a greater understanding of the role and appropriateness of neuroimaging techniques in the diagnosis of dementia.
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Affiliation(s)
| | | | - Catherine Quinn
- School of Psychology, Bangor University, Bangor, United Kingdom
| | - Linda Clare
- School of Psychology, University of Exeter, Exeter, United Kingdom
| | - Arun L. W. Bokde
- Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Paul G. Mullins
- School of Psychology, Bangor University, Bangor, United Kingdom
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Featherstone H, Butler ML, Ciblis A, Bokde AL, Mullins PG, McNulty JP. What do people with dementia and their carers want to know about neuroimaging for dementia? Dementia (London) 2015; 16:461-470. [PMID: 26330384 DOI: 10.1177/1471301215602576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Neuroimaging forms an important part of dementia diagnosis. Provision of information on neuroimaging to people with dementia and their carers may aid understanding of the pathological, physiological and psychosocial changes of the disease, and increase understanding of symptoms. This qualitative study aimed to investigate participants' knowledge of the dementia diagnosis pathway, their understanding of neuroimaging and its use in diagnosis, and to determine content requirements for a website providing neuroimaging information. Structured interviews and a focus group were conducted with carers and people with dementia. The findings demonstrate an unmet need for information on neuroimaging both before and after the examination. Carers were keen to know about neuroimaging at a practical and technical level to help avoid diagnosis denial. People with dementia requested greater information, but with a caveat to avoid overwhelming detail, and were less likely to favour an Internet resource.
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Affiliation(s)
| | - Marie-Louise Butler
- Diagnostic Imaging, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Aurelia Ciblis
- Diagnostic Imaging, School of Medicine and Medical Science, University College Dublin, Ireland
| | - Arun L Bokde
- Discipline of Psychiatry, School of Medicine and Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | | | - Jonathan P McNulty
- Diagnostic Imaging, School of Medicine and Medical Science, University College Dublin, Ireland
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Rusiak K, Mullins PG, Bokde AL, McNulty J. P2‐173: Transverse relaxation times of proton metabolites in ageing brain at 3 tesla: Effects on previously reported metabolite changes. Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.06.712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rusiak K, Mullins PG, Bokde AL, McNulty J. IC‐P‐148: Transverse relaxation times of proton metabolites in ageing brain at 3 tesla: Effects on previously reported metabolite changes. Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.06.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Apšvalka D, Gadie A, Clemence M, Mullins PG. Event-related dynamics of glutamate and BOLD effects measured using functional magnetic resonance spectroscopy (fMRS) at 3T in a repetition suppression paradigm. Neuroimage 2015; 118:292-300. [PMID: 26072254 DOI: 10.1016/j.neuroimage.2015.06.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/01/2015] [Accepted: 06/04/2015] [Indexed: 12/30/2022] Open
Abstract
Proton MR spectroscopy ((1)H-MRS) complements other brain research methods by providing measures of neurometabolites noninvasively in a localized brain area. Improvements in MR scanner technologies, and data acquisition and analysis methods should allow functional (1)H-MRS (fMRS) to measure neurometabolite concentration changes during task-induced brain activation. The aim of the current study was to further develop event-related fMRS at 3T to investigate glutamate dynamics in response to repetition suppression. A secondary aim was to investigate the relationship between blood-oxygen-level-dependent (BOLD) responses and glutamate dynamics in the same paradigm at the same time. A novel approach of interleaved water-suppressed (metabolite) and unsuppressed (water) fMRS was used to simultaneously detect the event-related dynamics of glutamate and BOLD signal to repetition suppression in the lateral occipital cortex of thirteen (N=13) volunteers. On average, (1)H-MRS-visible glutamate increased after novel visual stimuli presentations by 12% and decreased by 11-13% on repeated compared to novel presentations. The BOLD signal, as measured by water peak amplitude changes, showed significant difference between Task and Rest trials, and, on a GLM based analysis of the time series, demonstrated a significant difference between the novel and repeated trials, however appeared to be decoupled from the glutamate response as no correlation was found between the two. These results are the first demonstration that reductions in neuronal activity typical of repetition suppression effects are reflected by reduced glutamatergic and BOLD measures, that glutamate and BOLD responses may not be coupled as previously thought, and that these changes and relationships can be measured simultaneously using event-related fMRS at 3T.
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Affiliation(s)
- Dace Apšvalka
- Bangor Imaging Center, School of Psychology, Bangor University, Bangor, Gwynedd LL57 2AS, UK
| | - Andrew Gadie
- Bangor Imaging Center, School of Psychology, Bangor University, Bangor, Gwynedd LL57 2AS, UK
| | - Matthew Clemence
- Philips Healthcare, Philips Centre, Guildford Business Park, Guildford, Surrey GU2 8HX, UK
| | - Paul G Mullins
- Bangor Imaging Center, School of Psychology, Bangor University, Bangor, Gwynedd LL57 2AS, UK.
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Ciblis AS, Butler ML, Bokde ALW, Mullins PG, McNulty JP. The use of neuroimaging in dementia by Irish general practitioners. Ir J Med Sci 2015; 185:597-602. [PMID: 26048643 DOI: 10.1007/s11845-015-1315-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 05/16/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND More than 48,000 people in Ireland are living with dementia, and the number is likely to rise to 130,000 by 2041. Dementia frequently remains undiagnosed, depriving many of early interventions and the opportunity to plan for the future. Neuroimaging is helpful in the diagnosis of dementia, yet it is often insufficiently utilised. General practitioners (GPs) often decide which patients should be referred on for specialist assessment and as such play a crucial role in dementia diagnosis. AIMS To establish the accessibility of neuroimaging in dementia by GPs, current referral patterns, confidence in referral and opinions on radiology reports. METHODS The research design was a postal survey among GPs in single and group practices in urban, rural and semi-rural areas in the east and southeast of Ireland. GPs were identified from the Irish Medical Directory and posted individual anonymous questionnaires. RESULTS A third of participants reported that they had no direct access to neuroimaging. Access differed between public and private patients. GPs primarily referred to computed tomography and magnetic resonance imaging, but only 14.6 % based these referrals on published guidelines. A total of 47.8 % of participants were not very confident in their ability to choose the most appropriate modality. CONCLUSION Access to neuroimaging investigations for suspected cases of dementia varies between locations and public and private systems. To improve diagnostic rates and ensure appropriate utilisation of imaging resources, GPs require access to clinical and referral guidelines to ensure appropriate use of neuroimaging and the best possible patient outcomes.
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Affiliation(s)
- A S Ciblis
- UCD School of Medicine and Medical Science, Diagnostic Imaging, Room 223, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.
| | - M-L Butler
- UCD School of Medicine and Medical Science, Diagnostic Imaging, Room 223, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - A L W Bokde
- Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - P G Mullins
- School of Psychology, Bangor University, Bangor, UK
| | - J P McNulty
- UCD School of Medicine and Medical Science, Diagnostic Imaging, Room 223, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland
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Wilcox CE, Mayer AR, Teshiba TM, Ling J, Smith BW, Wilcox GL, Mullins PG. The Subjective Experience of Pain: An FMRI Study of Percept-Related Models and Functional Connectivity. Pain Med 2015; 16:2121-33. [PMID: 25989475 DOI: 10.1111/pme.12785] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Previous work suggests that the perception of pain is subjective and dependent on individual differences in physiological, emotional, and cognitive states. Functional magnetic resonance imaging (FMRI) studies have used both stimulus-related (nociceptive properties) and percept-related (subjective experience of pain) models to identify the brain networks associated with pain. Our objective was to identify the network involved in processing subjective pain during cold stimuli. METHODS The current FMRI study directly contrasted a stimulus-related model with a percept-related model during blocks of cold pain stimuli in healthy adults. Specifically, neuronal activation was modelled as a function of changes in stimulus intensity vs as a function of increasing/decreasing levels of subjective pain corresponding to changes in pain ratings. In addition, functional connectivity analyses were conducted to examine intrinsic correlations between three proposed subnetworks (sensory/discriminative, affective/motivational, and cognitive/evaluative) involved in pain processing. RESULTS The percept-related model captured more extensive activation than the stimulus-related model and demonstrated an association between higher subjective pain and activation in expected cortical (dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, insula, dorsal anterior cingulate cortex [dACC] extending into pre-supplementary motor area) and subcortical (thalamus, striatum) areas. Moreover, connectivity results supported the posited roles of dACC and insula as key relay sites during neural processing of subjective pain. In particular, anterior insula appeared to link sensory/discriminative regions with regions in the other subnetworks, and dACC appeared to serve as a hub for affective/motivational, cognitive/evaluative, and motor subnetworks. CONCLUSIONS Using a percept-related model, brain regions involved in the processing of subjective pain during the application of cold stimuli were identified. Connectivity analyses identified linkages between key subnetworks involved in processing subjective pain.
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Affiliation(s)
- Claire E Wilcox
- Department of Psychiatry, The University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Andrew R Mayer
- Mind Research Network, Albuquerque, NM 87131, USA.,Neurology Department, University of New Mexico School of Medicine, Albuquerque, New Mexico, 87131, USA.,Psychology Department, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Terri M Teshiba
- Mind Research Network, Albuquerque, NM 87131, USA.,Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095, USA
| | - Josef Ling
- Mind Research Network, Albuquerque, NM 87131, USA
| | - Bruce W Smith
- Psychology Department, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - George L Wilcox
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455, USA.,Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, 55455, USA.,Department of Dermatology, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Paul G Mullins
- Bangor Imaging Center, School of Psychology, Bangor University, Gwynedd, LL57 2AS, UK
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Ciblis AS, Butler ML, Bokde AL, Mullins PG, O'Neill D, McNulty JP. Neuroimaging referral for dementia diagnosis: The specialist's perspective in Ireland. Alzheimers Dement (Amst) 2015; 1:41-7. [PMID: 27239490 PMCID: PMC4876894 DOI: 10.1016/j.dadm.2014.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Neuroimaging is an increasingly important tool in the diagnostic workup of dementia. Neurologists, geriatricians, and old-age psychiatrists are involved in key tasks in the diagnostic process, frequently referring patients with suspected dementia for neuroimaging. METHODS The research design was a postal survey of all geriatricians, old-age psychiatrists, and neurologists in the Republic of Ireland (N = 176) as identified by the Irish Medical Directory 2011-2012 and supplementary listings. RESULTS Almost 65% of specialists did not have access to 2-[18F]fluoro-2-deoxy-D-glucose positron emission (FDG-PET) or FDG-PET/computed tomography (CT), and 80.3% did not have access to perfusion hexamethylpropyleneamine oxime single-photon emission computed tomography (SPECT) or dopaminergic iodine-123-radiolabeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane SPECT. Most specialists (88.7%) referred patients with mild cognitive impairment or suspected dementia for magnetic resonance imaging (MRI), 81.7% referred for CT, and 26.8% for FDG-PET or FDG-PET/CT. Only 44.6% of respondents were aware of dementia-specific protocols for referrals for neuroimaging. CONCLUSION Specialist access to imaging modalities other than CT and MRI is restricted. Improved access may affect patient treatment and care.
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Affiliation(s)
- Aurelia S. Ciblis
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Marie-Louise Butler
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Arun L.W. Bokde
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | | | - Desmond O'Neill
- Centre for Ageing, Neuroscience and the Humanities, Trinity College Dublin, Dublin, Ireland
| | - Jonathan P. McNulty
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
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22
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Kehoe EG, Farrell D, Metzler-Baddeley C, Lawlor BA, Kenny RA, Lyons D, McNulty JP, Mullins PG, Coyle D, Bokde AL. Fornix White Matter is Correlated with Resting-State Functional Connectivity of the Thalamus and Hippocampus in Healthy Aging but Not in Mild Cognitive Impairment - A Preliminary Study. Front Aging Neurosci 2015; 7:10. [PMID: 25698967 PMCID: PMC4318417 DOI: 10.3389/fnagi.2015.00010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 01/22/2015] [Indexed: 01/31/2023] Open
Abstract
In this study, we wished to examine the relationship between the structural connectivity of the fornix, a white matter (WM) tract in the limbic system, which is affected in amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease, and the resting-state functional connectivity (FC) of two key related subcortical structures, the thalamus, and hippocampus. Twenty-two older healthy controls (HC) and 18 older adults with aMCI underwent multi-modal MRI scanning. The fornix was reconstructed using constrained-spherical deconvolution-based tractography. The FC between the thalamus and hippocampus was calculated using a region-of-interest approach from which the mean time series were exacted and correlated. Diffusion tensor imaging measures of the WM microstructure of the fornix were correlated against the Fisher Z correlation values from the FC analysis. There was no difference between the groups in the fornix WM measures, nor in the resting-state FC of the thalamus and hippocampus. We did however find that the relationship between functional and structural connectivity differed significantly between the groups. In the HCs, there was a significant positive association between linear diffusion (CL) in the fornix and the FC of the thalamus and hippocampus, however, there was no relationship between these measures in the aMCI group. These preliminary findings suggest that in aMCI, the relationship between the functional and structural connectivity of regions of the limbic system may be significantly altered compared to healthy ageing. The combined use of diffusion weighted imaging and functional MRI may advance our understanding of neural network changes in aMCI, and elucidate subtle changes in the relationship between structural and functional brain networks.
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Affiliation(s)
- Elizabeth G Kehoe
- Trinity College Institute of Neuroscience and Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin , Dublin , Ireland
| | - Dervla Farrell
- Trinity College Institute of Neuroscience and Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin , Dublin , Ireland
| | - Claudia Metzler-Baddeley
- Cardiff University Brain Research Imaging Centre (CUBRIC), Neuroscience and Mental Health Research Institute (NMHRI), School of Psychology, Cardiff University , Cardiff , UK
| | - Brian A Lawlor
- Department of Psychiatry, Jonathan Swift Clinic, St. James Hospital, Trinity College Institute of Neuroscience, Trinity College Dublin , Dublin , Ireland
| | - Rose Anne Kenny
- Mercer's Institute for Successful Ageing, St. James Hospital, Trinity College Institute of Neuroscience, Trinity College Dublin , Dublin , Ireland
| | | | - Jonathan P McNulty
- School of Medicine and Medical Science, University College Dublin , Dublin , Ireland
| | | | - Damien Coyle
- Intelligent Systems Research Centre, University of Ulster , Derry , UK
| | - Arun L Bokde
- Trinity College Institute of Neuroscience and Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin , Dublin , Ireland
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Thoma RJ, Long J, Monnig M, Yeo RA, Petropoulos H, Gasparovic C, Pommy J, Mullins PG. 1H-MRS glutamate level predicts auditory sensory gating in alcohol dependence: Preliminary results. Neuropsychiatr Electrophysiol 2015; 1. [PMID: 34012554 PMCID: PMC8130891 DOI: 10.1186/s40810-015-0014-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background: Impairment in auditory sensory gating (ASG) has been documented in alcohol dependence [1]. Likewise, it has been shown that ASG becomes abnormal during alcohol administration in otherwise healthy individuals [2]. Patterns of gating abnormality associated with alcohol use are likely associated with an alcohol responsive neurochemical like glutamate (Glu), particularly since it is well-established that alcohol affects NMDA receptors and that glutamatergic functioning is abnormal in both acute alcohol use and in alcohol dependence [3]. Hence, a link between Glu metabolite levels and ASG was hypothesized. It was first hypothesized that Glu and ASG abnormality would be found in groups with alcohol dependence. A second hypothesis was that across groups, greater Glu would predict reduced ASG. Methods: Groups were comprised of healthy, non-drinking controls (Controls, N = 4), individuals with current alcohol dependence (AUD-current, N = 6), and with alcohol dependence in remission for at least 1 year (AUD-remission, N = 6). Participants underwent a diagnostic assessment for alcohol consumption, MRI, 1H-MRS for in vivo assessment of Glu and other metabolites, and MEG scanning during a paired click protocol. ASG was computed as the ratio of the source strength of the 50 ms component in the event related field (ERF) to the second click in the pair divided by the source strength of the 50 ms component to the first click in the pair. Results: Univariate MANOVAs controlling for age and gender revealed a significant effect for group on Glu and ASG, such that ASG ratios were significantly elevated, implying weakened gating. Glu concentration was reduced in AUD-current relative to the other two groups. Further analysis revealed that when additionally controlling for the group effect, reduced Glu predicted increasing impairment in ASG. Conclusions: The overall results were consistent with the hypothesis that differences in Glu metabolite levels associated with alcohol dependence result in impaired ASG.
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Affiliation(s)
- Robert J Thoma
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA.,Mind Research Network, Albuquerque, 1100 Yale NE, Albuquerque, NM, USA
| | - Jason Long
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Mollie Monnig
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA.,Center for Alcohol and Addiction Studies, Brown University, Box G-S121-5, Providence, RI 02912, USA
| | - Ronald A Yeo
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Helen Petropoulos
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Charles Gasparovic
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Jessica Pommy
- Departments of Psychiatry and Psychology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Paul G Mullins
- Bangor Imaging Unit, School of Psychology, Bangor University, Adeilad Brigantia, Penrallt Road, Bangor LL57 2ASGwynedd, UK
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Abstract
With the prevalence of Alzheimer's disease (AD) predicted to increase substantially over the coming decades, the development of effective biomarkers for the early detection of the disease is paramount. In this short review, the main neuroimaging techniques which have shown potential as biomarkers for AD are introduced, with a focus on MRI. Structural MRI measures of the hippocampus and medial temporal lobe are still the most clinically validated biomarkers for AD, but newer techniques such as functional MRI and diffusion tensor imaging offer great scope in tracking changes in the brain, particularly in functional and structural connectivity, which may precede gray matter atrophy. These new advances in neuroimaging methods require further development and crucially, standardization; however, before they are used as biomarkers to aid in the diagnosis of AD.
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Affiliation(s)
- Elizabeth G Kehoe
- The Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Jonathan P McNulty
- School of Medicine & Medical Science, University College Dublin, Dublin, Ireland
| | | | - Arun L W Bokde
- The Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
- Cognitive Systems Group, Discipline of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
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Rusiak K, Kehoe EG, McNulty J, Bokde AL, Mullins PG. P1‐294: POSTERIOR CINGULATE GLUTAMATE CHANGES IN AGING: A 1H‐MRS STUDY. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Goulden N, Khusnulina A, Davis NJ, Bracewell RM, Bokde AL, McNulty JP, Mullins PG. The salience network is responsible for switching between the default mode network and the central executive network: replication from DCM. Neuroimage 2014; 99:180-90. [PMID: 24862074 DOI: 10.1016/j.neuroimage.2014.05.052] [Citation(s) in RCA: 426] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/06/2014] [Accepted: 05/18/2014] [Indexed: 12/20/2022] Open
Abstract
With the advent of new analysis methods in neuroimaging that involve independent component analysis (ICA) and dynamic causal modelling (DCM), investigations have focused on measuring both the activity and connectivity of specific brain networks. In this study we combined DCM with spatial ICA to investigate network switching in the brain. Using time courses determined by ICA in our dynamic causal models, we focused on the dynamics of switching between the default mode network (DMN), the network which is active when the brain is not engaging in a specific task, and the central executive network (CEN), which is active when the brain is engaging in a task requiring attention. Previous work using Granger causality methods has shown that regions of the brain which respond to the degree of subjective salience of a stimulus, the salience network, are responsible for switching between the DMN and the CEN (Sridharan et al., 2008). In this work we apply DCM to ICA time courses representing these networks in resting state data. In order to test the repeatability of our work we applied this to two independent datasets. This work confirms that the salience network drives the switching between default mode and central executive networks and that our novel technique is repeatable.
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Lawley JS, Alperin N, Bagci AM, Lee SH, Mullins PG, Oliver SJ, Macdonald JH. Normobaric hypoxia and symptoms of acute mountain sickness: Elevated brain volume and intracranial hypertension. Ann Neurol 2014; 75:890-8. [PMID: 24788400 DOI: 10.1002/ana.24171] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 04/24/2014] [Accepted: 04/27/2014] [Indexed: 01/31/2023]
Abstract
OBJECTIVE The study was undertaken to determine whether normobaric hypoxia causes elevated brain volume and intracranial pressure in individuals with symptoms consistent with acute mountain sickness (AMS). METHODS Thirteen males age = (26 (sd 6)) years were exposed to normobaric hypoxia (12% O2 ) and normoxia (21% O2 ). After 2 and 10 hours, AMS symptoms were assessed alongside ventricular and venous vessel volumes, cerebral blood flow, regional brain volumes, and intracranial pressure, using high-resolution magnetic resonance imaging. RESULTS In normoxia, neither lateral ventricular volume (R(2) = 0.07, p = 0.40) nor predominance of unilateral transverse venous sinus drainage (R(2) = 0.07, p = 0.45) was related to AMS symptoms. Furthermore, despite an increase in cerebral blood flow after 2 hours of hypoxia (hypoxia vs normoxia: Δ148ml/min(-1) , 95% confidence interval [CI] = 58 to 238), by 10 hours, when AMS symptoms had developed, cerebral blood flow was normal (Δ-51ml/min(-1) , 95% CI = -141 to 39). Conversely, at 10 hours brain volume was increased (Δ59ml, 95% CI = 8 to 110), predominantly due to an increase in gray matter volume (Δ73ml, 95% CI = 25 to 120). Therefore, cerebral spinal fluid volume was decreased (Δ-40ml, 95% CI = -67 to -14). The intracranial pressure response to hypoxia varied between individuals, and as hypothesized, the most AMS-symptomatic participants had the largest increases in intracranial pressure (AMS present, Δ7mmHg, 95% CI = -2.5 to 17.3; AMS not present, Δ-1mmHg, 95% CI = -3.3 to 0.5). Consequently, there was a significant relationship between the change in intracranial pressure and AMS symptom severity (R(2) = 0.71, p = 0.002). INTERPRETATION The data provide the strongest evidence to date to support the hypothesis that the "random" nature of AMS symptomology is explained by a variable intracranial pressure response to hypoxia.
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Affiliation(s)
- Justin S Lawley
- Extremes Research Group, School of Sport, Health, and Exercise Sciences, Bangor University, Gwynedd, United Kingdom; Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX
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Lawley JS, Oliver SJ, Mullins PG, Macdonald JH, Moore JP. Prolonged (9 h) poikilocapnic hypoxia (12% O2) augments cutaneous thermal hyperaemia in healthy humans. Exp Physiol 2014; 99:909-20. [PMID: 24706191 DOI: 10.1113/expphysiol.2013.076562] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The primary aim of this study was to investigate the effect of systemic poikilocapnic hypoxia on forearm cutaneous thermal hyperaemia. A secondary aim was to examine the relationship between the individual susceptibility to oxygen desaturation and cutaneous vasodilator capacity. Twelve healthy participants (seven male) were exposed to 9 h of normoxia and 12% poikilocapnic hypoxia in a temperature- and humidity-controlled environmental chamber. Skin blood flow was assessed at the ventral forearm using laser Doppler flowmetry combined with rapid local heating. After 6 min at baseline (skin temperature clamped at 33°C), local skin temperature was elevated at a rate of 0.5°C every 5 s up to 42°C to elicit a sensory axon response and then held constant for 30 min to cause a plateau. Skin blood flow was calculated as cutaneous vascular conductance [CVC; in perfusion units/mean arterial blood pressure (APU mmHg(-1))] and expressed in raw format and relative to heating at 44°C in normoxia (%CVC44). During hypoxaemia, vasodilatation was greater during the initial peak (raw, Δ0.35 APU mmHg(-1), P = 0.09; %CVC44, Δ18%, P = 0.05) and the plateau phase (raw, Δ0.55 APU mmHg(-1), P = 0.03; %CVC44, Δ26%, P = 0.02). The rate of rise in cutaneous blood flow during the initial peak was significantly greater during poikilocapnic hypoxia (P < 0.01). We observed a negative relationship between oxygen saturation in poikilocapnic hypoxia and the change in baseline (P = 0.06), initial peak (P = 0.01) and plateau phase of thermal hyperaemia (P = 0.01). Prolonged poikilocapnic hypoxia causes robust increases in CVC during both phases of thermal hyperaemia that are dependent on the oxygen saturation of the individual.
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Affiliation(s)
- Justin S Lawley
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX, USA
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK
| | - Paul G Mullins
- Bangor Imaging Center, School of Psychology, Bangor University, Gwynedd, UK
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK
| | - Jonathan P Moore
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Gwynedd, UK
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Mullins PG, McGonigle DJ, O'Gorman RL, Puts NAJ, Vidyasagar R, Evans CJ, Edden RAE. Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA. Neuroimage 2012; 86:43-52. [PMID: 23246994 DOI: 10.1016/j.neuroimage.2012.12.004] [Citation(s) in RCA: 389] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 09/11/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022] Open
Abstract
There is increasing interest in the use of edited proton magnetic resonance spectroscopy for the detection of GABA in the human brain. At a recent meeting held at Cardiff University, a number of spectroscopy groups met to discuss the acquisition, analysis and interpretation of GABA-edited MR spectra. This paper aims to set out the issues discussed at this meeting, reporting areas of consensus around parameters and procedures in the field and highlighting those areas where differences remain. It is hoped that this paper can fulfill two needs, providing a summary of the current 'state-of-the-art' in the field of GABA-edited MRS at 3T using MEGA-PRESS and a basic guide to help researchers new to the field to avoid some of the pitfalls inherent in the acquisition and processing of edited MRS for GABA.
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Affiliation(s)
- Paul G Mullins
- Bangor Imaging Unit, School of Psychology, Bangor University, Bangor, LL57 2AS, UK.
| | - David J McGonigle
- CUBRIC, School of Psychology, Cardiff University, Cardiff, CF10 3AT, UK; School of Biosciences, Cardiff University, Cardiff, CF10 3AT, UK
| | - Ruth L O'Gorman
- University Children's Hospital, Steinwiesstrasse 75, 8032 Zürich, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zürich, Switzerland
| | - Nicolaas A J Puts
- Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 North Broadway Street, Room G-25, Baltimore, MD 21205, USA
| | - Rishma Vidyasagar
- Biomedical Imaging Institute, School of Cancer and Enabling Sciences, Manchester University, Stopford Building, Oxford Road, Manchester, M13 9PL, UK
| | - C John Evans
- CUBRIC, School of Psychology, Cardiff University, Cardiff, CF10 3AT, UK
| | | | - Richard A E Edden
- Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 North Broadway Street, Room G-25, Baltimore, MD 21205, USA
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Gasparovic CM, Roldan CA, Sibbitt WL, Qualls CR, Mullins PG, Sharrar JM, Yamamoto JJ, Bockholt HJ. Elevated cerebral blood flow and volume in systemic lupus measured by dynamic susceptibility contrast magnetic resonance imaging. J Rheumatol 2010; 37:1834-43. [PMID: 20551095 DOI: 10.3899/jrheum.091276] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Studies that have examined abnormalities in cerebral blood flow (CBF) in patients with systemic lupus erythematosus (SLE) reported CBF relative to a region assumed to be normal in the brain. We examined the absolute differences in both regional CBF and cerebral blood volume (CBV) between patients with SLE and healthy controls. METHODS CBF and CBV were measured with dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI), a technique that provides an alternative to radionuclide perfusion studies and permits quantitative anatomic, CBF, and CBV imaging in a single scanning session. CBF and CBV were measured in lesions and in normal-appearing tissue in the major cerebral and subcortical brain regions. Unlike most perfusion studies in SLE, CBF and CBV values were not normalized to a region of the brain assumed to be healthy. RESULTS CBF and CBV within MRI-visible lesions were markedly reduced relative to surrounding normal-appearing white matter. CBF and CBV in normal-appearing tissue were both higher in SLE patient groups, with or without lesions, relative to the control group. CONCLUSION DSC MRI, without normalization to a region presumed to be healthy, revealed that CBF and CBV in normal-appearing tissue in patients with SLE was higher than CBF and CBV in controls. Since this finding was made in subgroups of patients with and without lesions, the higher CBF and CBV appear to precede lesion pathology.
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Affiliation(s)
- Charles M Gasparovic
- Department of Psychology, Divisions of Cardiology and Rheumatology, University of New Mexico, 1101 Yale Blvd. NE, Albuquerque, NM 87106, USA.
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Gasparovic C, Neeb H, Feis DL, Damaraju E, Chen H, Doty MJ, South DM, Mullins PG, Bockholt HJ, Shah NJ. Quantitative spectroscopic imaging with in situ measurements of tissue water T1, T2, and density. Magn Reson Med 2009; 62:583-90. [PMID: 19526491 DOI: 10.1002/mrm.22060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The use of tissue water as a concentration standard in proton magnetic resonance spectroscopy ((1)H-MRS) of the brain requires that the water proton signal be adjusted for relaxation and partial volume effects. While single voxel (1)H-MRS studies have often included measurements of water proton T(1), T(2), and density based on additional (1)H-MRS acquisitions (e.g., at multiple echo or repetition times), this approach is not practical for (1)H-MRS imaging ((1)H-MRSI). In this report we demonstrate a method for using in situ measurements of water T(1), T(2), and density to calculate metabolite concentrations from (1)H-MRSI data. The relaxation and density data are coregistered with the (1)H-MRSI data and provide detailed information on the water signal appropriate to the individual subject and tissue region. We present data from both healthy subjects and a subject with brain lesions, underscoring the importance of water parameter measurements on a subject-by-subject and voxel-by-voxel basis.
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Affiliation(s)
- C Gasparovic
- Department of Neurology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
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Teshiba TM, Ling J, Mullins PG, Smith BW, Mayer AR. The Subjective Experience of Cold Pain: a Comparison of Stimulus-related vs. Percept-related fMRI. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)70282-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Smith BW, Tooley EM, Montague EQ, Robinson AE, Cosper CJ, Mullins PG. The role of resilience and purpose in life in habituation to heat and cold pain. J Pain 2009; 10:493-500. [PMID: 19345153 DOI: 10.1016/j.jpain.2008.11.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 09/29/2008] [Accepted: 11/10/2008] [Indexed: 02/08/2023]
Abstract
UNLABELLED This study examined the role of resilience in habituation to heat and cold pain in healthy women (n = 47). Heat and cold pain thresholds were each assessed across 5 equally spaced trials. Resilience, purpose in life, optimism, social support, and neuroticism were assessed using self-report measures. The hypothesis was that the resilience and the associated resilience factors would be positively related to habituation to heat and cold pain while controlling for neuroticism. Multilevel modeling was used to test the hypothesis. When considering each characteristic separately, resilience and purpose in life predicted greater habituation to heat pain while resilience, purpose in life, optimism, and social support predicted greater habituation to cold pain. When controlling for the other characteristics, both resilience and purpose in life predicted greater habituation to heat and cold pain. Resilience and associated characteristics such as a sense of purpose in life may be related to enhanced habituation to painful stimuli. Future research should further examine the relationship between resilience, purpose in life, and habituation to pain and determine whether psychosocial interventions that target resilience and purpose in life improve habituation and reduce vulnerability to chronic pain. PERSPECTIVE This article showed that resilience and a sense of purpose in life were both related to the ability to habituate to heat and cold pain in healthy women. These personal characteristics may enhance habituation to pain by providing the confidence and motivation to persist in the face of painful stimuli.
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Affiliation(s)
- Bruce W Smith
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
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Waters DL, Mullins PG, Qualls CR, Raj DSC, Gasparovic C, Baumgartner RN. Mitochondrial function in physically active elders with sarcopenia. Mech Ageing Dev 2009; 130:315-9. [PMID: 19428449 DOI: 10.1016/j.mad.2009.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 11/25/2008] [Accepted: 01/23/2009] [Indexed: 12/15/2022]
Abstract
Physical activity is reported to protect against sarcopenia and preserve mitochondrial function. Healthy normal lean (NL: n=15) and sarcopenic (SS: n=9) participants were recruited based on body composition (DXA, Lunar DPX), age, and physical activity. Gastrocnemius mitochondrial function was assessed by (31)P MRS using steady-state exercise in a 4T Bruker Biospin. Total work (429.3+/-160.2J vs. 851.0+/-211.7J, p<0.001) and muscle volume (p=0.006) were lower in SS, although these variables were not correlated (NL r=-0.31, p=0.33, SS r=(0.03, p=0.93). In the SS resting ATP/ADP was lower (p=0.03) and ATP hydrolysis higher (p=0.02) at rest. Free energy ATP hydrolysis was greater at the end of exercise (p=0.02) and [ADP] relative to total work output was higher in SS (ANCOVA, p=0.005). [PCr] recovery kinetics were not different between the groups. Adjusting these parameters for differences in total work output and muscle volume did not explain these findings. These data suggest that aerobic metabolism in physically active older adults with sarcopenia is mildly impaired at rest and during modest levels of exercise where acidosis was avoided. Muscle energetics is coordinated at multiple cellular levels and further studies are needed to determine the loci/locus of energy instability in sarcopenia.
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Affiliation(s)
- D L Waters
- University of New Mexico, Health Sciences Center, School of Medicine, Albuquerque, New Mexico, United States.
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35
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Smith BW, Tooley EM, Montague EQ, Robinson AE, Cosper CJ, Mullins PG. Habituation and sensitization to heat and cold pain in women with fibromyalgia and healthy controls. Pain 2008; 140:420-428. [PMID: 18947923 DOI: 10.1016/j.pain.2008.09.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 09/06/2008] [Accepted: 09/16/2008] [Indexed: 11/27/2022]
Abstract
The purpose of this study was to examine differences in habituation to heat and cold pain in women with fibromyalgia (FM; n=33) and in women who were healthy controls (HC; n=44). Quantitative sensory testing (QST) was used to assess pain thresholds during five consecutive trials of ascending heat and descending cold stimulation. Anxiety, depression, fatigue, and pain during the previous week were assessed using self-report measures. The overall hypotheses were that there would be differences between groups in pain thresholds and in the rate of habituation to heat and cold pain stimuli. Multilevel modeling was used to test the hypotheses. There were large overall differences in pain thresholds, with the FM group showing greater sensitivity to heat and cold pain stimuli compared with the HC group. While habituation occurred in both of the groups for heat pain, the HC group had stronger habituation across trials than the FM group. Conversely, while the HC group habituated to cold pain stimuli, the FM group showed sensitization and had decreased cold pain thresholds across trials (they felt cold pain at higher temperatures). In addition, anxiety, depression, fatigue, and pain were related to decreased heat and cold pain thresholds in the overall sample. However, when group was controlled, none of these variables were related to thresholds or rates of habituation or sensitization. The differences between women with FM and healthy women in habituation and sensitization may have important implications for the etiology, diagnosis, and treatment of FM and other chronic pain conditions.
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Affiliation(s)
- Bruce W Smith
- Department of Psychology, University of New Mexico, MSC03 2220, Albuquerque, NM 87131, USA School of Psychology, Bangor University, Addeliad Brigantia, Bangor, LL57 2AS, UK
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Gasparovic C, Song T, Devier D, Bockholt HJ, Caprihan A, Mullins PG, Posse S, Jung RE, Morrison LA. Use of tissue water as a concentration reference for proton spectroscopic imaging. Magn Reson Med 2006; 55:1219-26. [PMID: 16688703 DOI: 10.1002/mrm.20901] [Citation(s) in RCA: 365] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A strategy for using tissue water as a concentration standard in (1)H magnetic resonance spectroscopic imaging studies on the brain is presented, and the potential errors that may arise when the method is used are examined. The sensitivity of the method to errors in estimates of the different water compartment relaxation times is shown to be small at short echo times (TEs). Using data from healthy human subjects, it is shown that different image segmentation approaches that are commonly used to account for partial volume effects (SPM2, FSL's FAST, and K-means) lead to different estimates of metabolite levels, particularly in gray matter (GM), owing primarily to variability in the estimates of the cerebrospinal fluid (CSF) fraction. While consistency does not necessarily validate a method, a multispectral segmentation approach using FAST yielded the lowest intersubject variability in the estimates of GM metabolites. The mean GM and white matter (WM) levels of N-acetyl groups (NAc, primarily N-acetylaspartate), choline (Ch), and creatine (Cr) obtained in these subjects using the described method with FAST multispectral segmentation are reported: GM [NAc] = 17.16 +/- 1.19 mM; WM [NAc] = 14.26 +/- 1.38 mM; GM [Ch] = 3.27 +/- 0.47 mM; WM [Ch] = 2.65 +/- 0.25 mM; GM [Cr] = 13.98 +/- 1.20 mM; and WM [Cr] = 7.10 +/- 0.67 mM.
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Mullins PG, Rowland LM, Jung RE, Sibbitt WL. A novel technique to study the brain's response to pain: proton magnetic resonance spectroscopy. Neuroimage 2005; 26:642-6. [PMID: 15907322 DOI: 10.1016/j.neuroimage.2005.02.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 12/06/2004] [Accepted: 02/01/2005] [Indexed: 12/22/2022] Open
Abstract
Glutamate, a major excitatory neurotransmitter, has been implicated as an important mediator in the neurotransmission, potentiation, and negative affect associated with pain. We present results showing that a painful stimulus elicits a dynamic increase in glutamate (9.3% from baseline) concentrations in the anterior cingulate cortex, detectable using proton Magnetic Resonance Spectroscopy ((1)H-MRS). Increases in glutamine levels were also seen, which correlate strongly with the subjective level of pain experienced by participants (r(2) = 0.58, P < 0.01). These novel findings are the first time a dynamic change in glutamate and glutamine levels from baseline in response to an external stimuli has been measured in a single proton MRS scanning session. As such, this report demonstrates the efficacy of (1)H-MRS as a non-invasive tool for the study of neural responses to pain in vivo. The paradigm used in this study demonstrates that dynamic glutamate/glutamine changes due to stimulation are measurable by proton MRS, and could provide a means of testing novel pharmaceutical agents and other treatments for chronic pain.
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Affiliation(s)
- Paul G Mullins
- The MIND Imaging Center, a collaboration of the MIND Institute and the University of New Mexico, Albuquerque, 87131, USA
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Rowland LM, Bustillo JR, Mullins PG, Jung RE, Lenroot R, Landgraf E, Barrow R, Yeo R, Lauriello J, Brooks WM. Effects of ketamine on anterior cingulate glutamate metabolism in healthy humans: a 4-T proton MRS study. Am J Psychiatry 2005; 162:394-6. [PMID: 15677610 DOI: 10.1176/appi.ajp.162.2.394] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE The authors' goal was to test in humans the hypothesis that N-methyl-d-aspartate receptor (NMDAR) antagonism results in increased cortical glutamate activity, as proposed by the NMDAR hypofunction model of schizophrenia. METHOD 4-T 1H proton magnetic resonance spectroscopy (1H-MRS) was used to acquire in vivo spectra from the bilateral anterior cingulate of 10 healthy subjects while they received a subanesthetic dose of either placebo or ketamine, an NMDAR antagonist. Assessments given before and after ketamine or placebo administration included the Brief Rating Psychiatric Rating Scale, the Scale for the Assessment of Negative Symptoms, the Clinician-Administered Dissociative States Scale, and the Stroop task. RESULTS As predicted, there was a significant increase in anterior cingulate glutamine, a putative marker of glutamate neurotransmitter release, with ketamine administration. This increase was not related to schizophrenia-like positive or negative symptoms but was marginally related to Stroop performance. CONCLUSIONS In humans as in animals, an acute hypofunctional NMDAR state is associated with increased glutamatergic activity in the anterior cingulate.
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Affiliation(s)
- Laura M Rowland
- Department of Psychiatry, MIND Imaging Center, University of New Mexico, USA.
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Abstract
The reproducibility of single-voxel spectroscopic measures in a stable schizophrenic patient population is reported. Spectra acquired 1 week apart, in the left frontal white matter and left caudate nucleus of 12 patients, were analyzed using both frequency and time-domain techniques. No significant change in mean concentrations for N-acetylaspartate (NAA), choline (Cho), and creatine (Cre) were found between sessions. Variation from scan to scan was low for the left frontal white matter, with coefficients of variation (CV) < 5% for all three metabolites. NAA measures from the left caudate nucleus had similar reproducibility (CV = 5%), but Cho and Cre were poorer by comparison (CV = 16-18%). The two methods used for spectral analyses produced similar results, indicating that both techniques are appropriate. These results extend previous studies of healthy, normal subjects, and establish that it is possible to obtain reliable measures of brain metabolites in clinical populations.
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Affiliation(s)
- Paul G Mullins
- MIND Imaging Center, University of New Mexico, Albuquerque, New Mexico 87131, USA.
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Zohar O, Schreiber S, Getslev V, Schwartz JP, Mullins PG, Pick CG. Closed-head minimal traumatic brain injury produces long-term cognitive deficits in mice. Neuroscience 2003; 118:949-55. [PMID: 12732240 DOI: 10.1016/s0306-4522(03)00048-4] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Victims of minimal traumatic brain injury (mTBI) do not show clear morphological brain defects, but frequently suffer lasting cognitive deficits, emotional difficulties and behavioral disturbances. In the present study we adopted a non-invasive closed-head weight-drop mouse model to produce mTBI. We examined the effects of 20, 25, or 30 g weight drop 7, 30, 60 and 90 days following injury on mice's ability to perform the Morris water maze. The mice suffered profound long-lasting learning and memory deficits that were force- and time-dependent. Although the injured mice could acquire the task, they could not improve their initial escape latency by more than 50%, while normal mice improved by up to 450% (P<0.001). In order to directly compare the learning ability of individual mice following our mTBI we have devised a new measure which we term learning rate. We define learning rate as the rate the mouse improved its own performance in consecutive trials in a given experimental day. The learning rate of control mice increased linearly throughout the testing period with a slope of approximately 0.9. Injured mice that sustained 20 and 25 g weight drop could also improve their learning rate linearly but with a slope of only 0.2. Mice who sustained 30 g weight drop could not improve their learning rate linearly and reached a plateau after the third experimental learning day. These results indicate that the severity of injury may correlate with the degree of integration of the learning task. These cognitive deficits occurred without any other clear neurological damage, no evident brain edema, no notable damage to the blood-brain barrier and no early anatomical changes to the brain (observed by magnetic resonance imaging imaging). These results demonstrate that persistent deficits of cognitive learning abilities in mice, similar to those observed in human post-concussive syndrome, can follow mTBI without any anatomical damage to the brain and its surrounding tissue.
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Affiliation(s)
- O Zohar
- Blanchette Rockefeller Neurosciences Institute, West Virginia, Rockville, MD 20850, USA
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Vink R, Mullins PG, Temple MD, Bao W, Faden AI. Small shifts in craniotomy position in the lateral fluid percussion injury model are associated with differential lesion development. J Neurotrauma 2001; 18:839-47. [PMID: 11526990 DOI: 10.1089/089771501316919201] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous studies have shown that location and direction of injury may affect outcome in experimental models of traumatic brain injury. Significant variability in outcome data has also been noted in studies using the lateral fluid percussion brain injury model (FPI) in rats. In recent studies from our laboratory, we observed considerable variability in localization and severity of tissue damage as a function of small changes in craniotomy position. To further address this issue, we examined the relationship between craniotomy position and brain lesion size/location in rats subjected to moderate FPI (2.28 +/- 0.18 atmospheres). With placement of a 5-mm craniotomy adjacent to the sagittal suture, there was both ipsilateral and contralateral damage as detected at 3 weeks posttrauma using T2-weighted magnetic resonance imaging (MRI). The MRI lesions were generally restricted to the hippocampus and subcortical layers. Shifting of the craniotomy site laterally was associated with increased ipsilateral tissue damage and a greater cortical component that correlated with distance from the sagittal suture. In contrast, the contralateral MRI lesion did not change significantly in size or location unless the center of the craniotomy was placed more than 3.5 mm from the sagittal suture, under which condition contralateral damage could no longer be detected. Ipsilateral tissue damage as determined from the MRI scans was linearly correlated to motor outcome but not with cognitive outcome as assessed by the Morris Water Maze. We conclude that craniotomy position is critical in determining extent and location of tissue injury produced during the lateral FPI model in rats. Addressing such potential variability is essential for studies that address either injury mechanisms or therapeutic treatments.
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Affiliation(s)
- R Vink
- Department of Neuroscience, Georgetown University School of Medicine, Washington, DC, USA.
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Mullins PG, Reid DG, Hockings PD, Hadingham SJ, Campbell CA, Chalk JB, Doddrell DM. Ischaemic preconditioning in the rat brain: a longitudinal magnetic resonance imaging (MRI) study. NMR Biomed 2001; 14:204-209. [PMID: 11357186 DOI: 10.1002/nbm.703] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ischaemic preconditioning in rats was studied using MRI. Ischaemic preconditioning was induced, using an intraluminal filament method, by 30 min middle cerebral artery occlusion (MCAO), and imaged 24 h later. The secondary insult of 100 min MCAO was induced 3 days following preconditioning and imaged 24 and 72 h later. Twenty-four hours following ischaemic preconditioning most rats showed small sub-cortical hyperintense regions not seen in sham-preconditioned rats. Twenty-four hours and 72 h following the secondary insult preconditioned animals showed significantly smaller lesions (24 h = 112 +/- 31 mm(3), mean +/- standard error; 72 h = 80 +/- 35 mm(3)), which were confined to the striatum, than controls (24 h = 234 +/- 32 mm(3), p = 0.026; 72 h = 275 +/- 37 mm(3), p = 0.003). In addition during lesion maturation from 24 to 72 h post-secondary MCAO, preconditioned rats displayed an average reduction in lesion size as measured by MRI whereas sham-preconditioned rats displayed increases in lesion size; this is the first report of such differential lesion volume evolution in cerebral ischaemic preconditioning.
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Affiliation(s)
- P G Mullins
- Safety Assessment, GlaxoSmithKline, The Frythe, Welwyn, Herts AL6 9AR, UK
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Yakovlev AG, Di X, Movsesyan V, Mullins PG, Wang G, Boulares H, Zhang J, Xu M, Faden AI. Presence of DNA fragmentation and lack of neuroprotective effect in DFF45 knockout mice subjected to traumatic brain injury. Mol Med 2001; 7:205-16. [PMID: 11471558 PMCID: PMC1950023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND Apoptosis plays an important pathophysiologic role in neuronal cell loss and associated neurologic deficits following traumatic brain injury (TBI). DNA fragmentation represents one of the characteristic biochemical features of neuronal apoptosis and is observed after experimental TBI. DFF45 and DFF40 are essential for DNA fragmentation in various models of apoptosis. MATERIALS AND METHODS We used mice deficient in DFF45 and wild-type controls. Oligonucleosomal DNA fragmentation induced by TBI was analyzed using in vivo and in vitro assays. Expression and integrity of DFF45 and DFF40 proteins was assessed by Western analysis. Other outcome measurements included neurologic scoring, learning/memory tests, lesion volume measurements (MRI), and assessment of cell viability in vitro among others. RESULTS We compared the effects of controlled cortical impact (CCI) trauma in DFF45 knockout mice and wild-type controls. Analysis of TBI-induced DNA fragmentation in brain cortex from wild-type and DFF45 knockout mice indicates that, although somewhat delayed, oligonucleosomal cleavage of DNA occurs after TBI in DFF45 knockout mice. DFF45 knockouts showed no significant differences in behavioral outcomes or lesion volumes after TBI as compared to wild-type controls. Using an in vitro reconstitution system, we also demonstrated that cleavage of DFF45 by caspase-3 is not sufficient for DNA fragmentation induced by protein extracts from rat brain cortex. We found that endonuclease activity induced in rat brain cortex following TBI depends on the presence of Mg2+ and Ca2+, but is not inhibited by Zn2+. Primary neuronal cultures from DFF45 knockouts failed to show DNA laddering in response to staurosporine, but did show prominent, albeit delayed, DNA fragmentation following treatment with etoposide. In contrast, primary neurons from wild-type animals demonstrated marked DNA fragmentation following treatment with staurosporine or etoposide. CONCLUSIONS The results of this study suggest that, in addition to DFF45/40, other endonucleases may be essential for chromatin degradation during neuronal apoptosis in adult brain after TBI.
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Affiliation(s)
- A G Yakovlev
- Department of Neuroscience, Georgetown University, Washington, DC 20007, USA
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Faden AI, O'Leary DM, Fan L, Bao W, Mullins PG, Movsesyan VA. Selective blockade of the mGluR1 receptor reduces traumatic neuronal injury in vitro and improvesoOutcome after brain trauma. Exp Neurol 2001; 167:435-44. [PMID: 11161632 DOI: 10.1006/exnr.2000.7577] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of selective blockade of group I metabotropic glutamate receptor subtype 1 (mGluR1) on neuronal cell survival and post-traumatic recovery was examined using rat in vitro and in vivo trauma models. The selective mGluR1 antagonists (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA), 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt), and (S)-(+)-alpha-amino-4-carboxy-2-methylbezeneacetic acid (LY367385) provided significant neuroprotection in rat cortical neuronal cultures subjected to mechanical injury, in both pretreatment or posttreatment paradigms. Administration of the antagonists also attenuated glutamate-induced neuronal cell death in the cultures. Coapplication of these antagonists with the N-methyl-d-aspartate (NMDA) receptor antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) had additive neuroprotective effects in glutamate injured cultures. Intracerebroventricular administration of AIDA to rats markedly improved recovery from motor dysfunction after lateral fluid percussion induced traumatic brain injury (TBI). Treatment with mGluR1 antagonists also significantly reduced lesion volumes in rats after TBI, as evaluated by MRI. It appears that these compounds mediate their neuroprotective effect through an mGluR1 antagonist action, as demonstrated by inhibition of agonist induced phosphoinositide hydrolysis in our in vitro system. Moreover, AIDA, CPCCOEt, and LY367385, at concentrations shown to be neuroprotective, had no significant effects on the steady state NMDA evoked whole cell current. Taken together, these data suggest that modulation of mGluR1 activity may have substantial therapeutic potential in brain injury.
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Affiliation(s)
- A I Faden
- Georgetown Institute for Cognitive and Computational Sciences, Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20007, USA
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Movsesyan VA, O'Leary DM, Fan L, Bao W, Mullins PG, Knoblach SM, Faden AI. mGluR5 antagonists 2-methyl-6-(phenylethynyl)-pyridine and (E)-2-methyl-6-(2-phenylethenyl)-pyridine reduce traumatic neuronal injury in vitro and in vivo by antagonizing N-methyl-D-aspartate receptors. J Pharmacol Exp Ther 2001; 296:41-7. [PMID: 11123360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The effect of selective group I metabotropic glutamate receptor subtype 5 (mGluR5) antagonists 2-methyl-6-(phenylethynyl)-pyridine (MPEP) and (E)-2-methyl-6-(2-phenylethenyl)-pyridine (SIB-1893) on neuronal cell survival and post-traumatic recovery was examined using rat in vitro and in vivo trauma models. Treatment with MPEP and SIB-1893 showed significant neuroprotective effects in rat cortical neuronal cultures subjected to mechanical injury. Application of the antagonists also attenuated glutamate- and N-methyl-D-aspartate (NMDA)-induced neuronal cell death in vitro. Intracerebroventricular administration of MPEP to rats markedly improved motor recovery and reduced deficits of spatial learning after lateral fluid percussion-induced traumatic brain injury. Lesion volumes as assessed by magnetic resonance imaging were also substantially reduced by MPEP treatment. Although we show that MPEP acts as a potent mGluR5 antagonist in our culture system, where it completely blocks agonist-induced phosphoinositide hydrolysis, electrophysiological and pharmacological studies indicate that MPEP and SIB-1893 also inhibit NMDA receptor activity at higher concentrations that are neuroprotective. Taken together, these data suggest that MPEP and SIB-1893 may have therapeutic potential in brain injury, although the mechanisms of neuroprotective action for these drugs may reflect their ability to modulate NMDA receptor activity.
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Affiliation(s)
- V A Movsesyan
- Georgetown Institute for Cognitive and Computational Sciences, Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20007, USA
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Middleton DA, Bradley DP, Connor SC, Mullins PG, Reid DG. The effect of sample freezing on proton magic-angle spinning NMR spectra of biological tissue. Magn Reson Med 1998; 40:166-9. [PMID: 9660567 DOI: 10.1002/mrm.1910400122] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Magic-angle spinning (MAS) has recently been shown to enhance spectral resolution in NMR examinations of intact biological tissue ex vivo. This work demonstrates that freezing certain tissue samples before examination by 1H MAS NMR can have a marked effect on their spectra. Spectra of rat kidney after freezing in liquid nitrogen, compared with spectra before freezing, showed a significant increase in signal intensities from alanine (>100%), glutamine (>40%), and glycine (>100%), and a decrease in signals assigned to lipids and other macromolecules. Some resonances--such as from leucine, valine, isoleucine, and aspartate--only became visible after freezing the tissue. These observations suggest that low temperature storage of tissue necropsies or biopsies might affect the results of a MAS NMR analysis, possibly resulting in the misinterpretation of metabolite changes to pathogen or disease effects.
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Affiliation(s)
- D A Middleton
- Department of Analytical Sciences, SmithKline Beecham Pharmaceuticals, Herts, UK
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Abstract
Phosphorus magnetic resonance spectroscopy was used to determine effects of acute and chronic alcohol exposure on brain intracellular free magnesium concentration (Mgf) and bioenergetic state in rats. Acute alcohol (3 mg kg-1, i.p.) resulted in a transient ( < 2h) decline in brain Mgf and cytosolic phosphorylation ratio, and an increase in mitochondrial oxidative capacity. In contrast, chronic exposure to alcohol for 30 days by vapour inhalation resulted in a depletion of brain Mgf with no significant change in bioenergetic parameters. Subsequent exposure of chronically alcoholised rats to an acute dose of alcohol (3 g kg-1) did not result in any further changes. We conclude that chronic exposure to alcohol results in a depletion of brain Mgf and compromised bioenergetic regulation.
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Affiliation(s)
- P G Mullins
- Division of Biochemistry and Human Physiology, James Cook University of North Queensland, Townsville, Australia
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Popplewell PY, Chalmers JP, Burns RJ, Miller CD, Mullins PG. Peer review of utilisation of medical beds at Flinders Medical Centre. Aust N Z J Med 1984; 14:227-30. [PMID: 6594112 DOI: 10.1111/j.1445-5994.1984.tb03755.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A clinical audit of all medical inpatients was undertaken and the appropriateness of admissions and of length of stay was assessed from a clinical viewpoint on 4 separate days within an 11 day period. In addition, the mode of entry of hospital, length of stay of patients, occupancy rate, and the vacancy interval were analysed for all medical patients during the preceding three months. The mean length of stay of medical patients in hospital during this 3 months period was 5.6 days, with an occupancy rate of 93% and a vacancy interval of 0.43 days. Seventy-four percent of all medical inpatients were admitted through the Accident and Emergency Department (A&E). The short length of stay, high occupancy rate and low vacancy interval indicated that bed usage in the medical wards was efficient. A total of 493 reviews was carried out on 294 individual patients. In 87% of cases, both admission to hospital and length of stay were appropriate on clinical grounds alone. The number of patients whose admission to hospital (11), or length of stay (27) was not justified on medical grounds alone was 38 (13% of total patients). These patients were elderly, or had complex social and psychological problems contributing to their illness. It was concluded that stricter control of admissions or length of stay was unlikely to make a significant numbers of beds available for other admissions.
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