51
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Hansson B, Markenroth Bloch K, Owman T, Nilsson M, Lätt J, Olsrud J, Björkman-Burtscher IM. Subjectively Reported Effects Experienced in an Actively Shielded 7T MRI: A Large-Scale Study. J Magn Reson Imaging 2020; 52:1265-1276. [PMID: 32196818 DOI: 10.1002/jmri.27139] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Ultrahigh-field (UHF) MRI advances towards clinical use. Patient compliance is generally high, but few large-scale studies have investigated the effects experienced in 7T MRI systems, especially considering peripheral nerve stimulation (PNS) and caregiving. PURPOSE To evaluate the quantity, the intensity, and subjective experiences from short-term effects, focusing on the levels of comfort and compliance of subjects. STUDY TYPE Prospective. POPULATION In all, 954 consecutive MRIs in 801 subjects for 3 years. FIELD STRENGTH 7T. ASSESSMENT After the 7T examination, a questionnaire was used to collect data. STATISTICAL TESTS Descriptive statistics, Spearman's rank correlation, Mann-Whitney U-test, and t-test. RESULTS The majority (63%) of subjects agreed that the MRI experience was comfortable and 93% would be willing to undergo future 7T MRI as a patient (5% undecided) and 82% for research purposes (12% undecided). The most common short-term effects experienced were dizziness (81%), inconsistent movement (68%), PNS (63%), headache (40%), nausea (32%), metallic taste (12%), and light flashes (8%). Of the subjects who reported having PNS (n = 603), 44% experienced PNS as "not uncomfortable at all," 45% as "little or very little uncomfortable," and 11% as "moderate to very much uncomfortable." Scanner room temperature was experienced more comfortable before (78%) than during (58%) examinations, and the noise level was acceptable by 90% of subjects. Anxiety before the examination was reported by 43%. Patients differed from healthy volunteers regarding an experience of headache, metallic taste, dizziness, or anxiety. Room for improvement was pointed out after 117 examinations concerning given information (n = 73), communication and sound system (n = 35), or nursing care (n = 15). DATA CONCLUSION Subjectively reported effects occur in actively shielded 7T MRI and include physiological responses and individual psychological issues. Although leaving room for improvement, few subjects experienced these effects being so uncomfortable that they would lead to aversion to future UHF examinations. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY: Stage 5 J. Magn. Reson. Imaging 2020;52:1265-1276.
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Affiliation(s)
- Boel Hansson
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | | | - Titti Owman
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Markus Nilsson
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Jimmy Lätt
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Johan Olsrud
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden.,Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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52
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Lopez C, Toupet M, van Nechel C, Bozorg Grayeli A. Editorial: Role of Inner Ear in Self and Environment Perception. Front Neurol 2020; 11:22. [PMID: 32153485 PMCID: PMC7044406 DOI: 10.3389/fneur.2020.00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/08/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Michel Toupet
- Centre d'Explorations Fonctionnelles Otoneurologiques, Paris, France.,Institut de Recherche Oto-Neurologique (IRON), Paris, France
| | - Christian van Nechel
- Institut de Recherche Oto-Neurologique (IRON), Paris, France.,Clinique des Vertiges, Brussels, Belgium
| | - Alexis Bozorg Grayeli
- Otolaryngology Department, Dijon University Hospital, Université Bourgogne-Franche Comté, Dijon, France.,Electronic, Image and Computer Research Laboratory, Le2i, Dijon, France
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53
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Helmchen C, Machner B, Rother M, Spliethoff P, Göttlich M, Sprenger A. Effects of galvanic vestibular stimulation on resting state brain activity in patients with bilateral vestibulopathy. Hum Brain Mapp 2020; 41:2527-2547. [PMID: 32103579 PMCID: PMC7267973 DOI: 10.1002/hbm.24963] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 01/04/2023] Open
Abstract
We examined the effect of galvanic vestibular stimulation (GVS) on resting state brain activity using fMRI (rs‐fMRI) in patients with bilateral vestibulopathy. Based on our previous findings, we hypothesized that GVS, which excites the vestibular nerve fibers, (a) increases functional connectivity in temporoparietal regions processing vestibular signals, and (b) alleviates abnormal visual–vestibular interaction. Rs‐fMRI of 26 patients and 26 age‐matched healthy control subjects was compared before and after GVS. The stimulation elicited a motion percept in all participants. Using different analyses (degree centrality, DC; fractional amplitude of low frequency fluctuations [fALFF] and seed‐based functional connectivity, FC), group comparisons revealed smaller rs‐fMRI in the right Rolandic operculum of patients. After GVS, rs‐fMRI increased in the right Rolandic operculum in both groups and in the patients' cerebellar Crus 1 which was related to vestibular hypofunction. GVS elicited a fALFF increase in the visual cortex of patients that was inversely correlated with the patients' rating of perceived dizziness. After GVS, FC between parietoinsular cortex and higher visual areas increased in healthy controls but not in patients. In conclusion, short‐term GVS is able to modulate rs‐fMRI in healthy controls and BV patients. GVS elicits an increase of the reduced rs‐fMRI in the patients' right Rolandic operculum, which may be an important contribution to restore the disturbed visual–vestibular interaction. The GVS‐induced changes in the cerebellum and the visual cortex were associated with lower dizziness‐related handicaps in patients, possibly reflecting beneficial neural plasticity that might subserve visual–vestibular compensation of deficient self‐motion perception.
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Affiliation(s)
- Christoph Helmchen
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Björn Machner
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Matthias Rother
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Peer Spliethoff
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Martin Göttlich
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Andreas Sprenger
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany.,Institute of Psychology II, University of Lübeck, Lübeck, Germany
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54
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He X, Ertürk MA, Grant A, Wu X, Lagore RL, DelaBarre L, Eryaman Y, Adriany G, Auerbach EJ, Van de Moortele PF, Uğurbil K, Metzger GJ. First in-vivo human imaging at 10.5T: Imaging the body at 447 MHz. Magn Reson Med 2019; 84:289-303. [PMID: 31846121 DOI: 10.1002/mrm.28131] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 01/31/2023]
Abstract
PURPOSE To investigate the feasibility of imaging the human torso and to evaluate the performance of several radiofrequency (RF) management strategies at 10.5T. METHODS Healthy volunteers were imaged on a 10.5T whole-body scanner in multiple target anatomies, including the prostate, hip, kidney, liver, and heart. Phase-only shimming and spoke pulses were used to demonstrate their performance in managing the B 1 + inhomogeneity present at 447 MHz. Imaging protocols included both qualitative and quantitative acquisitions to show the feasibility of imaging with different contrasts. RESULTS High-quality images were acquired and demonstrated excellent overall contrast and signal-to-noise ratio. The experimental results matched well with predictions and suggested good translational capabilities of the RF management strategies previously developed at 7T. Phase-only shimming provided increased efficiency, but showed pronounced limitations in homogeneity, demonstrating the need for the increased degrees of freedom made possible through single- and multispoke RF pulse design. CONCLUSION The first in-vivo human imaging was successfully performed at 10.5T using previously developed RF management strategies. Further improvement in RF coils, transmit chain, and full integration of parallel transmit functionality are needed to fully realize the benefits of 10.5T.
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Affiliation(s)
- Xiaoxuan He
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - M Arcan Ertürk
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Andrea Grant
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Xiaoping Wu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Russell L Lagore
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Lance DelaBarre
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Yiğitcan Eryaman
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Gregor Adriany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Eddie J Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | | | - Kâmil Uğurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
| | - Gregory J Metzger
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota
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55
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Klaus MP, Wyssen GC, Frank SM, Malloni WM, Greenlee MW, Mast FW. Vestibular Stimulation Modulates Neural Correlates of Own-body Mental Imagery. J Cogn Neurosci 2019; 32:484-496. [PMID: 31682567 DOI: 10.1162/jocn_a_01496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
There is growing evidence that vestibular information is not only involved in reflexive eye movements and the control of posture but it also plays an important role in higher order cognitive processes. Previous behavioral research has shown that concomitant vestibular stimuli influence performance in tasks that involve imagined self-rotations. These results suggest that imagined and perceived body rotations share common mechanisms. However, the nature and specificity of these effects remain largely unknown. Here, we investigated the neural mechanisms underlying this vestibulocognitive interaction. Participants (n = 20) solved an imagined self-rotation task during caloric vestibular stimulation. We found robust main effects of caloric vestibular stimulation in the core region of the vestibular network, including the rolandic operculum and insula bilaterally, and of the cognitive task in parietal and frontal regions. Interestingly, we found an interaction of stimulation and task in the left inferior parietal lobe, suggesting that this region represents the modulation of imagined body rotations by vestibular input. This result provides evidence that the inferior parietal lobe plays a crucial role in the neural integration of mental and physical body rotation.
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56
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Mouse Magnetic-field Nystagmus in Strong Static Magnetic Fields Is Dependent on the Presence of Nox3. Otol Neurotol 2019; 39:e1150-e1159. [PMID: 30444848 DOI: 10.1097/mao.0000000000002024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS Magnetic vestibular stimulation (MVS) elicits nystagmus in C57BL/6J mice but not head tilt mice lacking Nox3, which is required for normal otoconial development. BACKGROUND Humans have vertigo and nystagmus in strong magnetic fields within magnetic resonance imaging machines. The hypothesized mechanism is a Lorentz force driven by electrical current entering the utricular neuroepithelium, acting indirectly on crista hair cells via endolymph movement deflecting cupulae. We tested an alternate hypothesized mechanism: Lorentz action directly on crista hair cell stereocilia, driven by their currents independent of the utricle. METHODS Before MVS, vestibulo-ocular reflex responses of eight C57BL/6J mice and six head tilt mice were measured during whole-body sinusoidal rotations and tilts using video-oculography. Mice were then placed within a 4.7 Tesla magnetic field with the horizontal semicircular canals approximately Earth-horizontal for ≥1 minute in several head orientations, while eye movements were recorded via infrared video in darkness. RESULTS Outside the magnet, both C57BL/6J and head tilt mice had intact horizontal vestibulo-ocular reflex, but only C57BL/6J mice exhibited static counter-roll responses to tilt (normal utiruclo-ocular reflex). When placed in the magnet nose-first, C57BL/6J mice had left-beating nystagmus, lasting a median of 32.8 seconds. When tail-first, nystagmus was right-beating and similar duration (median 28.0 s, p > 0.05). In contrast, head tilt mice lacked magnetic field-induced nystagmus (p < 0.001). CONCLUSIONS C57BL/6J mice generate nystagmus in response to MVS, while mice deficient in Nox3 do not. This suggests 1) a normal utricle is necessary, and 2) functioning semicircular canals are insufficient, to generate MVS-induced nystagmus in mice.
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57
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Devantier L, Hansen AK, Mølby-Henriksen JJ, Christensen CB, Pedersen M, Hansen KV, Magnusson M, Ovesen T, Borghammer P. Positron emission tomography visualized stimulation of the vestibular organ is localized in Heschl's gyrus. Hum Brain Mapp 2019; 41:185-193. [PMID: 31520516 PMCID: PMC7268041 DOI: 10.1002/hbm.24798] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 08/12/2019] [Accepted: 09/04/2019] [Indexed: 11/10/2022] Open
Abstract
The existence of a human primary vestibular cortex is still debated. Current knowledge mainly derives from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) acquisitions during artificial vestibular stimulation. This may be problematic as artificial vestibular stimulation entails coactivation of other sensory receptors. The use of fMRI is challenging as the strong magnetic field and loud noise during MRI may both stimulate the vestibular organ. This study aimed to characterize the cortical activity during natural stimulation of the human vestibular organ. Two fluorodeoxyglucose (FDG)-PET scans were obtained after natural vestibular stimulation in a self-propelled chair. Two types of stimuli were applied: (a) rotation (horizontal semicircular canal) and (b) linear sideways movement (utriculus). A comparable baseline FDG-PET scan was obtained after sitting motion-less in the chair. In both stimulation paradigms, significantly increased FDG uptake was measured bilaterally in the medial part of Heschl's gyrus, with some overlap into the posterior insula. This is the first neuroimaging study to visualize cortical processing of natural vestibular stimuli. FDG uptake was demonstrated in the medial-most part of Heschl's gyrus, normally associated with the primary auditory cortex. This anatomical localization seems plausible, considering that the labyrinth contains both the vestibular organ and the cochlea.
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Affiliation(s)
- Louise Devantier
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Allan K Hansen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | | | | | | | - Kim V Hansen
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Måns Magnusson
- Department of Oto-Rhino-Laryngology, Lund University Hospital, Lund, Sweden
| | - Therese Ovesen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Oto-Rhino-Laryngology, Regional Hospital West Jutland, Holstebro, Denmark
| | - Per Borghammer
- Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Aarhus, Denmark
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58
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Eggers SD, Bisdorff A, von Brevern M, Zee DS, Kim JS, Perez-Fernandez N, Welgampola MS, Della Santina CC, Newman-Toker DE. Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements. J Vestib Res 2019; 29:57-87. [PMID: 31256095 PMCID: PMC9249296 DOI: 10.3233/ves-190658] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations. View accompanying videos at http://www.jvr-web.org/ICVD.html
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Affiliation(s)
| | - Alexandre Bisdorff
- Department of Neurology, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg
| | - Michael von Brevern
- Private Practice of Neurology and Department of Neurology, Charité, Berlin, Germany
| | - David S. Zee
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, Korea
| | | | - Miriam S. Welgampola
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - Charles C. Della Santina
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David E. Newman-Toker
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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59
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Ertl M, Boegle R. Investigating the vestibular system using modern imaging techniques-A review on the available stimulation and imaging methods. J Neurosci Methods 2019; 326:108363. [PMID: 31351972 DOI: 10.1016/j.jneumeth.2019.108363] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023]
Abstract
The vestibular organs, located in the inner ear, sense linear and rotational acceleration of the head and its position relative to the gravitational field of the earth. These signals are essential for many fundamental skills such as the coordination of eye and head movements in the three-dimensional space or the bipedal locomotion of humans. Furthermore, the vestibular signals have been shown to contribute to higher cognitive functions such as navigation. As the main aim of the vestibular system is the sensation of motion it is a challenging system to be studied in combination with modern imaging methods. Over the last years various different methods were used for stimulating the vestibular system. These methods range from artificial approaches like galvanic or caloric vestibular stimulation to passive full body accelerations using hexapod motion platforms, or rotatory chairs. In the first section of this review we provide an overview over all methods used in vestibular stimulation in combination with imaging methods (fMRI, PET, E/MEG, fNIRS). The advantages and disadvantages of every method are discussed, and we summarize typical settings and parameters used in previous studies. In the second section the role of the four imaging techniques are discussed in the context of vestibular research and their potential strengths and interactions with the presented stimulation methods are outlined.
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Affiliation(s)
- Matthias Ertl
- Department of Psychology, University of Bern, Switzerland; Sleep-Wake-Epilepsy Center, Department of Neurology, University Hospital (Inselspital) Bern, Switzerland.
| | - Rainer Boegle
- Department of Neurology, Ludwig-Maximilians-Universität München, Germany; German Center for Vertigo and Balance Disorders, IFB-LMU, Ludwig-Maximilians Universität, Munich, Germany
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60
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Hoff MN, McKinney A, Shellock FG, Rassner U, Gilk T, Watson RE, Greenberg TD, Froelich J, Kanal E. Safety Considerations of 7-T MRI in Clinical Practice. Radiology 2019; 292:509-518. [PMID: 31310177 DOI: 10.1148/radiol.2019182742] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although 7-T MRI has recently received approval for use in clinical patient care, there are distinct safety issues associated with this relatively high magnetic field. Forces on metallic implants and radiofrequency power deposition and heating are safety considerations at 7 T. Patient bioeffects such as vertigo, dizziness, false feelings of motion, nausea, nystagmus, magnetophosphenes, and electrogustatory effects are more common and potentially more pronounced at 7 T than at lower field strengths. Herein the authors review safety issues associated with 7-T MRI. The rationale for safety concerns at this field strength are discussed as well as potential approaches to mitigate risk to patients and health care professionals.
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Affiliation(s)
- Michael N Hoff
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Alexander McKinney
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Frank G Shellock
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Ulrich Rassner
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Tobias Gilk
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Robert E Watson
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Todd D Greenberg
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Jerry Froelich
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
| | - Emanuel Kanal
- From the Department of Radiology, University of Washington, 1959 NE Pacific St, Seattle, WA 98195-7117 (M.N.H.); Department of Radiology, University of Minnesota, Minneapolis, Minn (A.M., J.F.); Department of Clinical Physical Therapy, University of Southern California, Los Angeles, Calif (F.G.S.); Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, Utah (U.R.); RADIOLOGY-Planning, Kansas City, Mo (T.G.); Department of Radiology, Mayo Clinic, Rochester, Minn (R.E.W.); G3 Global Group, Boulder, Colo, Mo (T.D.G.); and Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pa (E.K.)
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Leong ATL, Gu Y, Chan YS, Zheng H, Dong CM, Chan RW, Wang X, Liu Y, Tan LH, Wu EX. Optogenetic fMRI interrogation of brain-wide central vestibular pathways. Proc Natl Acad Sci U S A 2019; 116:10122-10129. [PMID: 31028140 PMCID: PMC6525493 DOI: 10.1073/pnas.1812453116] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Blood oxygen level-dependent functional MRI (fMRI) constitutes a powerful neuroimaging technology to map brain-wide functions in response to specific sensory or cognitive tasks. However, fMRI mapping of the vestibular system, which is pivotal for our sense of balance, poses significant challenges. Physical constraints limit a subject's ability to perform motion- and balance-related tasks inside the scanner, and current stimulation techniques within the scanner are nonspecific to delineate complex vestibular nucleus (VN) pathways. Using fMRI, we examined brain-wide neural activity patterns elicited by optogenetically stimulating excitatory neurons of a major vestibular nucleus, the ipsilateral medial VN (MVN). We demonstrated robust optogenetically evoked fMRI activations bilaterally at sensorimotor cortices and their associated thalamic nuclei (auditory, visual, somatosensory, and motor), high-order cortices (cingulate, retrosplenial, temporal association, and parietal), and hippocampal formations (dentate gyrus, entorhinal cortex, and subiculum). We then examined the modulatory effects of the vestibular system on sensory processing using auditory and visual stimulation in combination with optogenetic excitation of the MVN. We found enhanced responses to sound in the auditory cortex, thalamus, and inferior colliculus ipsilateral to the stimulated MVN. In the visual pathway, we observed enhanced responses to visual stimuli in the ipsilateral visual cortex, thalamus, and contralateral superior colliculus. Taken together, our imaging findings reveal multiple brain-wide central vestibular pathways. We demonstrate large-scale modulatory effects of the vestibular system on sensory processing.
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Affiliation(s)
- Alex T L Leong
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Yong Gu
- Institute of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Hairong Zheng
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Celia M Dong
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Russell W Chan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Xunda Wang
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Yilong Liu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Li Hai Tan
- Center for Language and Brain, Shenzhen Institute of Neuroscience, Shenzhen 518057, China
| | - Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China;
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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62
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Ward BK, Roberts DC, Otero-Millan J, Zee DS. A decade of magnetic vestibular stimulation: from serendipity to physics to the clinic. J Neurophysiol 2019; 121:2013-2019. [PMID: 30969883 DOI: 10.1152/jn.00873.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For many years, people working near strong static magnetic fields of magnetic resonance imaging (MRI) machines have reported dizziness and sensations of vertigo. The discovery a decade ago that a sustained nystagmus can be observed in all humans with an intact labyrinth inside MRI machines led to a possible mechanism: a Lorentz force occurring in the labyrinth from the interactions of normal inner ear ionic currents and the strong static magnetic fields of the MRI machine. Inside an MRI, the Lorentz force acts to induce a constant deflection of the semicircular canal cupula of the superior and lateral semicircular canals. This inner ear stimulation creates a sensation of rotation, and a constant horizontal/torsional nystagmus that can only be observed when visual fixation is removed. Over time, the brain adapts to both the perception of rotation and the nystagmus, with the perception usually diminishing over a few minutes, and the nystagmus persisting at a reduced level for hours. This observation has led to discoveries about how the central vestibular mechanisms adapt to a constant vestibular asymmetry and is a useful model of set-point adaptation or how homeostasis is maintained in response to changes in the internal milieu or the external environment. We review what is known about the effects of stimulation of the vestibular system with high-strength magnetic fields and how the understanding of the mechanism has been refined since it was first proposed. We suggest future ways that magnetic vestibular stimulation might be used to understand vestibular disease and how it might be treated.
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Affiliation(s)
- Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine , Baltimore, Maryland
| | - Dale C Roberts
- Department of Neurology, The Johns Hopkins University School of Medicine , Baltimore, Maryland
| | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University School of Medicine , Baltimore, Maryland
| | - David S Zee
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine , Baltimore, Maryland.,Department of Neurology, The Johns Hopkins University School of Medicine , Baltimore, Maryland.,Department of Neuroscience, The Johns Hopkins University School of Medicine , Baltimore, Maryland.,Department of Ophthalmology, The Johns Hopkins University School of Medicine , Baltimore, Maryland
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63
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Hansson B, Höglund P, Markenroth Bloch K, Nilsson M, Olsrud J, Wilén J, Björkman-Burtscher IM. Short-term effects experienced during examinations in an actively shielded 7 T MR. Bioelectromagnetics 2019; 40:234-249. [PMID: 30920671 PMCID: PMC6593459 DOI: 10.1002/bem.22189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 03/12/2019] [Indexed: 01/18/2023]
Abstract
The objective of this study was to evaluate occurrence and strength of short-term effects experienced by study participants in an actively shielded (AS) 7 tesla (7 T) magnetic resonance (MR) scanner, to compare results with earlier reports on passively shielded (PS) 7 T MR scanners, and to outline possible healthcare strategies to improve patient compliance. Study participants (n = 124) completed a web-based questionnaire directly after being examined in an AS 7 T MR (n = 154 examinations). Most frequently experienced short-term effects were dizziness (84%) and inconsistent movement (70%), especially while moving into or out of the magnet. Peripheral nerve stimulation (PNS)-twitching-was experienced in 67% of research examinations and showed a dependence between strength of twitches and recorded predicted PNS values. Of the participants, 74% experienced noise levels as acceptable and the majority experienced body and room temperature as comfortable. Of the study participants, 95% felt well-informed and felt they had had good contact with the staff before the examination. Willingness to undergo a future 7 T examination was high (>90%). Our study concludes short-term effects are often experienced during examinations in an AS 7 T MR, leaving room for improvement in nursing care strategies to increase patient compliance. Bioelectromagnetics. 2019;9999:XX-XX. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Boel Hansson
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Peter Höglund
- Department of Clinical Pharmacology, Lund University, Lund, Sweden
| | | | - Markus Nilsson
- Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Johan Olsrud
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Jonna Wilén
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Diagnostic Radiology, Skåne University Hospital, Lund, Sweden.,Department of Diagnostic Radiology, Clinical Sciences, Lund University, Lund, Sweden.,Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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64
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Aranda-Moreno C, Jáuregui-Renaud K, Reyes-Espinosa J, Andrade-Galicia A, Bastida-Segura AE, González Carrazco LG. Stimulation of the Semicircular Canals or the Utricles by Clinical Tests Can Modify the Intensity of Phantom Limb Pain. Front Neurol 2019; 10:117. [PMID: 30863355 PMCID: PMC6399116 DOI: 10.3389/fneur.2019.00117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 01/29/2019] [Indexed: 11/13/2022] Open
Abstract
Background: After amputation, phantom limb pain may be produced by the multisensory processes underling the experience of an intact body. Clinical evidence has shown that cold caloric vestibular stimulation may modify the perception of phantom limb pain. However, it is yet unknown if this effect can be observed after the mild vestibular stimulation given by the clinical caloric test, or after utricle stimulation by centrifugation. Additionally, there are no studies on the association between the report of altered perceptions or experience of the self or the environment (depersonalization/derealization symptoms) and phantom limb pain. Objective: To assess the influence of unilateral stimulation of the horizontal semicircular canals by clinical caloric test, and the utricles by unilateral centrifugation on the intensity of phantom limb pain, and to explore the association between phantom limb pain and symptoms of depersonalization/ derealization. Methods: 34 patients (56 ±7 years old, 23 men) accepted to participate after 3 to 23 months of unilateral supracondylar amputation, secondary to type 2 diabetes mellitus. After assessment of vestibular function and symptoms of common mental disorders, using a cross-over design, in 2 separate sessions with 1 week in between, vestibular stimulation was delivered by right/left caloric test (30 or 44°C) or right/ left centrifugation (3.85 cm, 300°/s peak). Before and after each vestibular stimulus, the intensity of phantom limb pain and depersonalization/derealization symptoms were assessed, with a daily follow-up of pain intensity during 1 week. Results: Either caloric stimulation or unilateral centrifugation decreased phantom limb pain (p < 0.05), along with decrease of symptoms of depersonalization/derealization (p < 0.05). One third of the patients reporting pain decrease immediately after stimulation also reported no pain at least for 1 day. Limitations: No sham condition was included. Conclusions: Vestibular stimulation by the clinical caloric tests or by unilateral centrifugation may decrease the intensity of phantom limb pain, with decrease of perceptions of unreality. These effects might be related to an update of the immediate experience of the body, given by the sensory mismatch induced by asymmetrical vestibular stimulation.
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Affiliation(s)
- Catalina Aranda-Moreno
- Unidad de Investigación Médica en Otoneurología, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Kathrine Jáuregui-Renaud
- Unidad de Investigación Médica en Otoneurología, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Jaime Reyes-Espinosa
- Hospital General de Zona 1"A", Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | | | - Ana E Bastida-Segura
- Hospital General de Zona 47, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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65
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Ward BK, Zee DS, Roberts DC, Schubert MC, Pérez-Fernández N, Otero-Millan J. Visual Fixation and Continuous Head Rotations Have Minimal Effect on Set-Point Adaptation to Magnetic Vestibular Stimulation. Front Neurol 2019; 9:1197. [PMID: 30723456 PMCID: PMC6349782 DOI: 10.3389/fneur.2018.01197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 12/31/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Strong static magnetic fields such as those in an MRI machine can induce sensations of self-motion and nystagmus. The proposed mechanism is a Lorentz force resulting from the interaction between strong static magnetic fields and ionic currents in the inner ear endolymph that causes displacement of the semicircular canal cupulae. Nystagmus persists throughout an individual's exposure to the magnetic field, though its slow-phase velocity partially declines due to adaptation. After leaving the magnetic field an after effect occurs in which the nystagmus and sensations of rotation reverse direction, reflecting the adaptation that occurred while inside the MRI. However, the effects of visual fixation and of head shaking on this early type of vestibular adaptation are unknown. Methods: Three-dimensional infrared video-oculography was performed in six individuals just before, during (5, 20, or 60 min) and after (4, 15, or 20 min) lying supine inside a 7T MRI scanner. Trials began by entering the magnetic field in darkness followed 60 s later, either by light with visual fixation and head still, or by continuous yaw head rotations (2 Hz) in either darkness or light with visual fixation. Subjects were always placed in darkness 10 or 30 s before exiting the bore. In control conditions subjects remained in the dark with the head still for the entire duration. Results: In darkness with head still all subjects developed horizontal nystagmus inside the magnetic field, with slow-phase velocity partially decreasing over time. An after effect followed on exiting the magnet, with nystagmus in the opposite direction. Nystagmus was suppressed during visual fixation; however, after resuming darkness just before exiting the magnet, nystagmus returned with velocity close to the control condition and with a comparable after effect. Similar after effects occurred with continuous yaw head rotations while in the scanner whether in darkness or light. Conclusions: Visual fixation and sustained head shaking either in the dark or with fixation inside a strong static magnetic field have minimal impact on the short-term mechanisms that attempt to null unwanted spontaneous nystagmus when the head is still, so called VOR set-point adaptation. This contrasts with the critical influence of vision and slippage of images on the retina on the dynamic (gain and direction) components of VOR adaptation.
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Affiliation(s)
- Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, United States
| | - David S Zee
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, United States.,Department of Neurology, The Johns Hopkins University, Baltimore, MD, United States.,Department of Neuroscience, The Johns Hopkins University, Baltimore, MD, United States.,Department of Ophthalmology, The Johns Hopkins University, Baltimore, MD, United States
| | - Dale C Roberts
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, United States.,Department of Neurology, The Johns Hopkins University, Baltimore, MD, United States
| | - Michael C Schubert
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, United States.,Department of Physical Medicine and Rehabilitation, The Johns Hopkins University, Baltimore, MD, United States
| | | | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, United States
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66
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Impact of extremely low-frequency magnetic fields on human postural control. Exp Brain Res 2018; 237:611-623. [DOI: 10.1007/s00221-018-5442-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/21/2018] [Indexed: 01/28/2023]
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67
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Hartwig V, Virgili G, Ferrante Vero LF, De Marchi D, Landini L, Giovannetti G. TOWARDS A PERSONALISED AND INTERACTIVE ASSESSMENT OF OCCUPATIONAL EXPOSURE TO MAGNETIC FIELD DURING DAILY ROUTINE IN MAGNETIC RESONANCE. RADIATION PROTECTION DOSIMETRY 2018; 182:546-554. [PMID: 30053260 DOI: 10.1093/rpd/ncy114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
Magnetic resonance imaging (MRI) is one of the most common sources of electromagnetic (EM) fields as a diagnostic technique widely used in medicine. MRI staff during the working day is constantly exposed to static and spatially heterogeneous magnetic field. Also, moving around the MRI room to perform their functions, workers are exposed to slowly time-varying magnetic fields that induce electrical currents and fields in the body. The development of new exposure assessment methodologies to collect exposure data at a personal level using simple everyday equipment is hence necessary, also in view of future epidemiological studies. This paper describes the design and testing of a novel device for assessing personal exposure to static and time-varying magnetic fields during daily clinical practice. The dosemeter will be also used to ensure effective training of technicians who will be instructed to avoid, where possible, risk behaviour in terms of high exposure.
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Affiliation(s)
- Valentina Hartwig
- Institute of Clinical Physiology, CNR, Via Moruzzi 1, Pisa, Italy
- Fondazione CNR-Regione Toscana 'G. Monasterio', Via Moruzzi 1, Pisa, Italy
| | | | | | - Daniele De Marchi
- Fondazione CNR-Regione Toscana 'G. Monasterio', Via Moruzzi 1, Pisa, Italy
- Associazione Italiana Tecnici dell'Imaging in Risonanza Magnetica, AITIRM, via XX Settembre 76, Firenze, Italy
| | - Luigi Landini
- Fondazione CNR-Regione Toscana 'G. Monasterio', Via Moruzzi 1, Pisa, Italy
| | - Giulio Giovannetti
- Institute of Clinical Physiology, CNR, Via Moruzzi 1, Pisa, Italy
- Fondazione CNR-Regione Toscana 'G. Monasterio', Via Moruzzi 1, Pisa, Italy
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68
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Gurrera D, Gallias KK, Spanò M, Abbate BF, D'Alia F, Iacoviello G, Caputo V. Moving across the static magnetic field of a 1.5 T MRI scanner: Analysing compliance with Directive 2013/35/EU. Phys Med 2018; 57:238-244. [PMID: 30470532 DOI: 10.1016/j.ejmp.2018.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/13/2018] [Accepted: 11/06/2018] [Indexed: 02/07/2023] Open
Abstract
Does the exposure of magnetic resonance imaging personnel to static magnetic fields fully comply with Directive 2013/35/EU? Despite the obligation to satisfy this question, a general answer cannot be provided, nor are final satisfying good practices methods for exposure assessment currently available. In order to contribute to fix this problem, three different 1.5 T scanners are analysed and - by a new theoretical insight - a positive answer is provided.
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Affiliation(s)
- Davide Gurrera
- Università degli Studi di Palermo, Dipartimento di Fisica e Chimica, Viale delle Scienze Ed. 18, 90128 Palermo, Italy.
| | - Karmenos K Gallias
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Marco Spanò
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Boris F Abbate
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Francesca D'Alia
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Giuseppina Iacoviello
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Vittorio Caputo
- A.R.N.A.S. Civico Di Cristina Benfratelli, U.O.C. Fisica Sanitaria, Piazza Nicola Leotta 4, 90127 Palermo, Italy
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69
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An fMRI study of visuo-vestibular interactions following vestibular neuritis. NEUROIMAGE-CLINICAL 2018; 20:1010-1017. [PMID: 30336357 PMCID: PMC6197146 DOI: 10.1016/j.nicl.2018.10.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 10/01/2018] [Accepted: 10/08/2018] [Indexed: 11/22/2022]
Abstract
Vestibular neuritis (VN) is characterised by acute vertigo due to a sudden loss of unilateral vestibular function. A considerable proportion of VN patients proceed to develop chronic symptoms of dizziness, including visually induced dizziness, specifically during head turns. Here we investigated whether the development of such poor clinical outcomes following VN, is associated with abnormal visuo-vestibular cortical processing. Accordingly, we applied functional magnetic resonance imaging to assess brain responses of chronic VN patients and compared these to controls during both congruent (co-directional) and incongruent (opposite directions) visuo-vestibular stimulation (i.e. emulating situations that provoke symptoms in patients). We observed a focal significant difference in BOLD signal in the primary visual cortex V1 between patients and controls in the congruent condition (small volume corrected level of p < .05 FWE). Importantly, this reduced BOLD signal in V1 was negatively correlated with functional status measured with validated clinical questionnaires. Our findings suggest that central compensation and in turn clinical outcomes in VN are partly mediated by adaptive mechanisms associated with the early visual cortex. VN clinical status related to V1 response to congruent visuo-vestibular stimuli Reduced V1 BOLD signal during congruent stimulation correlates with subjective dizziness scores No association between V1 BOLD signal and incongruent visuo-vestibular stimulation Changes in V1 activity may reflect cortical adaptive mechanisms following VN
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70
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Cortés-Domínguez I, Burguete J. Instabilities triggered in different conducting fluid geometries due to slowly time-dependent magnetic fields. CHAOS (WOODBURY, N.Y.) 2018; 28:075514. [PMID: 30070514 DOI: 10.1063/1.5027674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The main objective of this work is the study and analysis of non-linearities forced through oscillating magnetic fields in a conducting fluid where the instabilities are triggered due to magnetohydrodynamic forces. Different geometries have been studied and different surface patterns that break the symmetries have been observed. First, an InGaSn drop of fluid where the system breaks the azimuthal and radial symmetries depending on the volume is observed. Second, we extend the study to an InGaSn annular configuration where the presence of patterns opens the door to discuss the possibility to extend these results to other configurations as biological systems, where the conducting fluid is an electrolyte. This configuration has an added interest, as it has been proposed that the vertigoes triggered on patients in an MRI test could be generated by the interaction of the magnetic field with the electrolyte present in the inner ear.
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Affiliation(s)
- I Cortés-Domínguez
- Physics and Applied Mathematics Department, School of Science, University of Navarra, Irunlarrea 1, E-31008 Pamplona, Spain
| | - J Burguete
- Physics and Applied Mathematics Department, School of Science, University of Navarra, Irunlarrea 1, E-31008 Pamplona, Spain
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71
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Budinger TF, Bird MD. MRI and MRS of the human brain at magnetic fields of 14 T to 20 T: Technical feasibility, safety, and neuroscience horizons. Neuroimage 2018; 168:509-531. [DOI: 10.1016/j.neuroimage.2017.01.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 11/16/2022] Open
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72
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Mucci V, Cha YH, Wuyts FL, Van Ombergen A. Perspective: Stepping Stones to Unraveling the Pathophysiology of Mal de Debarquement Syndrome with Neuroimaging. Front Neurol 2018; 9:42. [PMID: 29483889 PMCID: PMC5816028 DOI: 10.3389/fneur.2018.00042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/17/2018] [Indexed: 01/07/2023] Open
Abstract
Mal de debarquement syndrome (MdDS) is a neurological condition typically characterized by a sensation of motion, which in most cases manifests after disembarking from a vehicle (e.g., boat, plane, and car). However, the same symptoms can also occur spontaneously. Two main theories of the pathophysiology of MdDS are briefly summarized here. In this perspective, we aimed to report the most recent findings on neuroimaging studies related to MdDS, as well as to suggest further potential research questions that could be addressed with the use of neuroimaging techniques. A detailed analysis of previous work on MdDS has led to five main research questions that could be addressed in new neuroimaging studies. Furthermore, in this perspective, we propose new stepping-stones to addressing critical research questions related to MdDS and its pathophysiology. We propose considerations for new studies, as well as a detailed analysis of the current limitations and challenges present when studying MdDS patients. We hope that our examination of the nuances of MdDS as a neurological disorder will contribute to more directed research on this topic.
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Affiliation(s)
- Viviana Mucci
- Antwerp University Research Centre for Equilibrium and Aerospace, Department of Biomedical Physics, Faculty of Sciences, University of Antwerp, Antwerp, Belgium
| | - Yoon-Hee Cha
- Laureate Institute for Brain Research, Tulsa, OK, United States
| | - Floris L Wuyts
- Antwerp University Research Centre for Equilibrium and Aerospace, Department of Biomedical Physics, Faculty of Sciences, University of Antwerp, Antwerp, Belgium
| | - Angelique Van Ombergen
- E.N.T., Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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73
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Zee DS. A neurologist and ataxia: using eye movements to learn about the cerebellum. CEREBELLUM & ATAXIAS 2018; 5:2. [PMID: 29445510 PMCID: PMC5804057 DOI: 10.1186/s40673-018-0081-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/25/2018] [Indexed: 11/22/2022]
Abstract
The cerebellum, its normal functions and its diseases, and especially its relation to the control of eye movements, has been at the heart of my academic career. Here I review how this came about, with an emphasis on epiphanies, "tipping points" and the influences of mentors, colleagues and trainees. I set a path for young academicians, both clinicians and basic scientists, with some guidelines for developing a productive and rewarding career in neuroscience.
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Affiliation(s)
- David S. Zee
- Departments of Neurology, Ophthalamology, Otolaryngology-Head and Neck Surgery, and Neuroscience, The Johns Hopkins University School of Medicine, The Johns Hopkins Hospital, Path 2-210, Baltimore, MD 21287 USA
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74
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Cortés-Domínguez I, Burguete J. Instabilities of conducting fluid layers in weak time-dependent magnetic fields. Phys Rev E 2018; 96:013103. [PMID: 29347070 DOI: 10.1103/physreve.96.013103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Indexed: 11/07/2022]
Abstract
We present the experimental analysis of the instabilities generated on a large drop of liquid metal by a time-dependent magnetic field. The study is done exploring the range of tiny values of the control parameter (the ratio between the Lorentz forces and inertia) avoiding nonlinear effects. Two different instabilities break the symmetries generating spatial patterns that appear without a threshold for some specific frequencies (up to the experimental precision) and have been observed for parameter values two orders of magnitude lower than in previously published experiments [J. Fluid Mech. 239, 383 (1992)JFLSA70022-112010.1017/S0022112092004452]. One of the instabilities corresponds to a boundary condition oscillation that generates surface waves and breaks the azimuthal symmetry. The other corresponds to a parametric forcing through a modulation of the Lorentz force. The competition between these two mechanisms produces time-dependent patterns near codimension-2 points.
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Affiliation(s)
- I Cortés-Domínguez
- Departamento de Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, Navarra, Spain
| | - J Burguete
- Departamento de Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, Navarra, Spain
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75
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76
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Zee DS, Jareonsettasin P, Leigh RJ. Ocular stability and set-point adaptation. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0199. [PMID: 28242733 DOI: 10.1098/rstb.2016.0199] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2016] [Indexed: 11/12/2022] Open
Abstract
A fundamental challenge to the brain is how to prevent intrusive movements when quiet is needed. Unwanted limb movements such as tremor impair fine motor control and unwanted eye drifts such as nystagmus impair vision. A stable platform is also necessary to launch accurate movements. Accordingly, nature has designed control systems with agonist (excitation) and antagonist (inhibition) muscle pairs functioning in push-pull, around a steady level of balanced tonic activity, the set-point Sensory information can be organized similarly, as in the vestibulo-ocular reflex, which generates eye movements that compensate for head movements. The semicircular canals, working in coplanar pairs, one in each labyrinth, are reciprocally excited and inhibited as they transduce head rotations. The relative change in activity is relayed to the vestibular nuclei, which operate around a set-point of stable balanced activity. When a pathological imbalance occurs, producing unwanted nystagmus without head movement, an adaptive mechanism restores the proper set-point and eliminates the nystagmus. Here we used 90 min of continuous 7 T magnetic field labyrinthine stimulation (MVS) in normal humans to produce sustained nystagmus simulating vestibular imbalance. We identified multiple time-scale processes towards a new zero set-point showing that MVS is an excellent paradigm to investigate the neurobiology of set-point adaptation.This article is part of the themed issue 'Movement suppression: brain mechanisms for stopping and stillness'.
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Affiliation(s)
- D S Zee
- Department of Neurology, Johns Hopkins Hospital, 600 N. Wolfe St, Baltimore, MD 21287, USA
| | - P Jareonsettasin
- Oxford University Hospitals, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - R J Leigh
- Department of Neurology, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-5040, USA
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Kromhout H, Slottje P, Huss A, van Nierop LE, Bongers S, Schaap K, de Vocht F. ICNIRP Statement on Diagnostic Devices Using Non-Ionizing Radiation: Existing Regulations and Potential Health Risks. HEALTH PHYSICS 2017; 113:149-150. [PMID: 28658061 DOI: 10.1097/hp.0000000000000686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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78
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Ward BK, Otero-Millan J, Jareonsettasin P, Schubert MC, Roberts DC, Zee DS. Magnetic Vestibular Stimulation (MVS) As a Technique for Understanding the Normal and Diseased Labyrinth. Front Neurol 2017; 8:122. [PMID: 28424657 PMCID: PMC5380677 DOI: 10.3389/fneur.2017.00122] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 03/15/2017] [Indexed: 12/03/2022] Open
Abstract
Humans often experience dizziness and vertigo around strong static magnetic fields such as those present in an MRI scanner. Recent evidence supports the idea that this effect is the result of inner ear vestibular stimulation and that the mechanism is a magnetohydrodynamic force (Lorentz force) that is generated by the interactions between normal ionic currents in the inner ear endolymph and the strong static magnetic field of MRI machines. While in the MRI, the Lorentz force displaces the cupula of the lateral and anterior semicircular canals, as if the head was rotating with a constant acceleration. If a human subject’s eye movements are recorded when they are in darkness in an MRI machine (i.e., without fixation), there is a persistent nystagmus that diminishes but does not completely disappear over time. When the person exits the magnetic field, there is a transient aftereffect (nystagmus beating in the opposite direction) that reflects adaptation that occurred in the MRI. This magnetic vestibular stimulation (MVS) is a useful technique for exploring set-point adaptation, the process by which the brain adapts to a change in its environment, which in this case is vestibular imbalance. Here, we review the mechanism of MVS, how MVS produces a unique stimulus to the labyrinth that allows us to explore set-point adaptation, and how this technique might apply to the understanding and treatment of vestibular and other neurological disorders.
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Affiliation(s)
- Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, USA
| | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA
| | - Prem Jareonsettasin
- Department of Neuroscience, Exeter College, University of Oxford, Oxford, UK
| | - Michael C Schubert
- Department of Neuroscience, Exeter College, University of Oxford, Oxford, UK.,Department of Physical Medicine and Rehabilitation, The Johns Hopkins University, Baltimore, MD, USA
| | - Dale C Roberts
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, USA.,Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA
| | - David S Zee
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD, USA.,Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA.,Department of Neuroscience, The Johns Hopkins University, Baltimore, MD, USA.,Department of Ophthalmology, The Johns Hopkins University, Baltimore, MD, USA
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79
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Static Magnetic Field Stimulation over Parietal Cortex Enhances Somatosensory Detection in Humans. J Neurosci 2017; 37:3840-3847. [PMID: 28280254 DOI: 10.1523/jneurosci.2123-16.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 02/25/2017] [Accepted: 03/01/2017] [Indexed: 02/07/2023] Open
Abstract
The role of neuronal oscillations in human somatosensory perception is currently unclear. To address this, here we use noninvasive brain stimulation to artificially modulate cortical network dynamics in the context of neurophysiological and behavioral recordings. We demonstrate that transcranial static magnetic field stimulation (tSMS) over the somatosensory parietal cortex increases oscillatory power specifically in the alpha range, without significantly affecting bottom-up thalamocortical inputs indexed by the early cortical component of somatosensory evoked potentials. Critically, we next show that parietal tSMS enhances the detection of near-threshold somatosensory stimuli. Interestingly, this behavioral improvement reflects a decrease of habituation to somatosensation. Our data therefore provide causal evidence that somatosensory perception depends on parietal alpha activity.SIGNIFICANCE STATEMENT Artificially increasing alpha power by placing a powerful magnetic field over the somatosensory cortex overcomes the natural decline in detection probability of a repeated near-threshold sensory stimulus.
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80
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Boegle R, Ertl M, Stephan T, Dieterich M. Magnetic vestibular stimulation influences resting-state fluctuations and induces visual-vestibular biases. J Neurol 2017; 264:999-1001. [PMID: 28271404 DOI: 10.1007/s00415-017-8447-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/01/2017] [Indexed: 10/20/2022]
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81
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Three-dimensional eye movement recordings during magnetic vestibular stimulation. J Neurol 2017; 264:7-12. [DOI: 10.1007/s00415-017-8420-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 02/06/2017] [Indexed: 10/20/2022]
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82
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ICNIRP Statement on Diagnostic Devices Using Non-ionizing Radiation: Existing Regulations and Potential Health Risks. HEALTH PHYSICS 2017; 112:305-321. [PMID: 28121732 PMCID: PMC5515634 DOI: 10.1097/hp.0000000000000654] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Use of non-ionizing radiation (NIR) for diagnostic purposes allows non-invasive assessment of the structure and function of the human body and is widely employed in medical care. ICNIRP has published previous statements about the protection of patients during medical magnetic resonance imaging (MRI), but diagnostic methods using other forms of NIR have not been considered. This statement reviews the range of diagnostic NIR devices currently used in clinical settings; documents the relevant regulations and policies covering patients and health care workers; reviews the evidence around potential health risks to patients and health care workers exposed to diagnostic NIR; and identifies situations of high NIR exposure from diagnostic devices in which patients or health care workers might not be adequately protected by current regulations. Diagnostic technologies were classified by the types of NIR that they employ. The aim was to describe the techniques in terms of general device categories which may encompass more specific devices or techniques with similar scientific principles. Relevant legally-binding regulations for protection of patients and workers and organizations responsible for those regulations were summarized. Review of the epidemiological evidence concerning health risks associated with exposure to diagnostic NIR highlighted a lack of data on potential risks to the fetus exposed to MRI during the first trimester, and on long-term health risks in workers exposed to MRI. Most of the relevant epidemiological evidence that is currently available relates to MRI or ultrasound. Exposure limits are needed for exposures from diagnostic technologies using optical radiation within the body. There is a lack of data regarding risk of congenital malformations following exposure to ultrasound in utero in the first trimester and also about the possible health effects of interactions between ultrasound and contrast media.
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83
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Kim SJ, Kim KA. Safety issues and updates under MR environments. Eur J Radiol 2017; 89:7-13. [PMID: 28267552 DOI: 10.1016/j.ejrad.2017.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 11/18/2022]
Abstract
Magnetic resonance (MR) imaging is a useful imaging tool with superior soft tissue contrast for diagnostic evaluation. The MR environments poses unique risks to patients and employees differently from ionizing radiation exposure originated from computed tomography and plain x-ray films. The technology associated with MR system has evolved continuously since its introduction in the late 1970s. MR systems have advanced with static magnetic fields, faster and stronger gradient magnetic fields and more powerful radiofrequency transmission coils. Higher field strengths of MR offers greater signal to noise capability and better spatial resolution, resulting in better visualization of anatomic detail, with a reduction in scan time. With the rapid evolution of technology associated with MR, we encounter new MR-related circumstances and unexpected dangerous conditions. A comprehensive update of our knowledge about MR safety is necessary to prevent MR-related accidents and to ensure safety for patients and staff associated with MR. This review presents an overview about MR-related safety issues and updates.
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Affiliation(s)
- Soo Jung Kim
- Department of Radiology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung Ah Kim
- Department of Radiology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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84
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Kirollos R, Allison RS, Palmisano S. Cortical Correlates of the Simulated Viewpoint Oscillation Advantage for Vection. Multisens Res 2017. [DOI: 10.1163/22134808-00002593] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Behavioural studies have consistently found stronger vection responses for oscillating, compared to smooth/constant, patterns of radial flow (the simulated viewpoint oscillation advantage for vection). Traditional accounts predict that simulated viewpoint oscillation should impair vection by increasing visual–vestibular conflicts in stationary observers (as this visual oscillation simulates self-accelerations that should strongly stimulate the vestibular apparatus). However, support for increased vestibular activity during accelerating vection has been mixed in the brain imaging literature. This fMRI study examined BOLD activity in visual (cingulate sulcus visual area — CSv; medial temporal complex — MT+; V6; precuneus motion area — PcM) and vestibular regions (parieto-insular vestibular cortex — PIVC/posterior insular cortex — PIC; ventral intraparietal region — VIP) when stationary observers were exposed to vection-inducing optic flow (i.e., globally coherent oscillating and smooth self-motion displays) as well as two suitable control displays. In line with earlier studies in which no vection occurred, CSv and PIVC/PIC both showed significantly increased BOLD activity during oscillating global motion compared to the other motion conditions (although this effect was found for fewer subjects in PIVC/PIC). The increase in BOLD activity in PIVC/PIC during prolonged exposure to the oscillating (compared to smooth) patterns of global optical flow appears consistent with vestibular facilitation.
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Affiliation(s)
- Ramy Kirollos
- Centre for Vision Research, York University, Toronto, ON, M3J 1P3, Canada
| | - Robert S. Allison
- Centre for Vision Research, York University, Toronto, ON, M3J 1P3, Canada
| | - Stephen Palmisano
- Centre for Psychophysics, Psychophysiology, and Psychopharmacology
- School of Psychology, University of Wollongong, Wollongong, NSW, 2522, Australia
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85
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Van Ombergen A, Heine L, Jillings S, Roberts RE, Jeurissen B, Van Rompaey V, Mucci V, Vanhecke S, Sijbers J, Vanhevel F, Sunaert S, Bahri MA, Parizel PM, Van de Heyning PH, Laureys S, Wuyts FL. Altered functional brain connectivity in patients with visually induced dizziness. NEUROIMAGE-CLINICAL 2017; 14:538-545. [PMID: 28331800 PMCID: PMC5345975 DOI: 10.1016/j.nicl.2017.02.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/06/2017] [Accepted: 02/24/2017] [Indexed: 02/06/2023]
Abstract
Background Vestibular patients occasionally report aggravation or triggering of their symptoms by visual stimuli, which is called visually induced dizziness (VID). These patients therefore experience dizziness, discomfort, disorientation and postural unsteadiness. The underlying pathophysiology of VID is still poorly understood. Objective The aim of the current explorative study was to gain a first insight in the underlying neural aspects of VID. Methods We included 10 VID patients and 10 healthy matched controls, all of which underwent a resting state fMRI scan session. Changes in functional connectivity were explored by means of the intrinsic connectivity contrast (ICC). Seed-based analysis was subsequently performed in visual and vestibular seeds. Results We found a decreased functional connectivity in the right central operculum (superior temporal gyrus), as well as increased functional connectivity in the occipital pole in VID patients as compared to controls in a hypothesis-free analysis. A weaker functional connectivity between the thalamus and most of the right putamen was measured in VID patients in comparison to controls in a seed-based analysis. Furthermore, also by means of a seed-based analysis, a decreased functional connectivity between the visual associative area and the left parahippocampal gyrus was found in VID patients. Additionally, we found increased functional connectivity between thalamus and occipital and cerebellar areas in the VID patients, as well as between the associative visual cortex and both middle frontal gyrus and precuneus. Conclusions We found alterations in the visual and vestibular cortical network in VID patients that could underlie the typical VID symptoms such as a worsening of their vestibular symptoms when being exposed to challenging visual stimuli. These preliminary findings provide the first insights into the underlying functional brain connectivity in VID patients. Future studies should extend these findings by employing larger sample sizes, by investigating specific task-based paradigms in these patients and by exploring the implications for treatment. Visually-induced patients present decreased functional connectivity of vestibular-related brain regions. Visually-induced dizziness patients present increased functional connectivity of visual and cerebellar brain regions. These findings might underlie typically seen symptoms in visually-induced dizziness, i.e. an overreliance on visual cues. This is the first exploratory study investigating the underlying neural aspects of visually-induced dizziness. These preliminary findings should be extended by larger sample sizes and by supplementing rsfMRI with task-based paradigms.
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86
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Roberts RE, Ahmad H, Arshad Q, Patel M, Dima D, Leech R, Seemungal BM, Sharp DJ, Bronstein AM. Functional neuroimaging of visuo-vestibular interaction. Brain Struct Funct 2016; 222:2329-2343. [PMID: 27942855 PMCID: PMC5504268 DOI: 10.1007/s00429-016-1344-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 11/19/2016] [Indexed: 12/21/2022]
Abstract
The brain combines visual, vestibular and proprioceptive information to distinguish between self- and world motion. Often these signals are complementary and indicate that the individual is moving or stationary with respect to the surroundings. However, conflicting visual motion and vestibular cues can lead to ambiguous or false sensations of motion. In this study, we used functional magnetic resonance imaging to explore human brain activation when visual and vestibular cues were either complementary or in conflict. We combined a horizontally moving optokinetic stimulus with caloric irrigation of the right ear to produce conditions where the vestibular activation and visual motion indicated the same (congruent) or opposite directions of self-motion (incongruent). Visuo-vestibular conflict was associated with increased activation in a network of brain regions including posterior insular and transverse temporal areas, cerebellar tonsil, cingulate and medial frontal gyri. In the congruent condition, there was increased activation in primary and secondary visual cortex. These findings suggest that when sensory information regarding self-motion is contradictory, there is preferential activation of multisensory vestibular areas to resolve this ambiguity. When cues are congruent, there is a bias towards visual cortical activation. The data support the view that a network of brain areas including the posterior insular cortex may play an important role in integrating and disambiguating visual and vestibular cues.
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Affiliation(s)
- R E Roberts
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK.
| | - H Ahmad
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK
| | - Q Arshad
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK
| | - M Patel
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK
| | - D Dima
- Department of Psychology, City, University of London, London, UK.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - R Leech
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - B M Seemungal
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK
| | - D J Sharp
- Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - A M Bronstein
- Neuro-otology Unit, Division of Brain Sciences, Charing Cross Hospital, Imperial College London, London, UK.
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87
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Jokela K, Laakso I. Dielectric polarization transients in biological tissue moving in a static magnetic field. Bioelectromagnetics 2016; 37:409-22. [DOI: 10.1002/bem.21979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/26/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Kari Jokela
- Radiation and Nuclear Safety Authority (STUK); Helsinki Finland
| | - Ilkka Laakso
- Department of Electrical Engineering and Automation; Aalto University School of Electrical Engineering; Espoo Finland
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88
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Bonello J, Sammut CV. Experimental analysis of radiographer exposure to the static field from a 1.5-T magnetic resonance imaging machine. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2016; 23:133-138. [PMID: 27458053 DOI: 10.1080/10803548.2016.1216357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION This study measures the exposure of occupational therapists from a 1.5-T magnetic resonance imaging (MRI) machine. METHOD A total of 14 time-series on each of the chest, head and hand were taken before and after different MRI procedures. The peak values were noted in each case together with an average of all data recorded in the time-series. RESULTS The highest exposure recorded was observed on the hand, followed by the head and the chest. The overall maximum exposure (1479.40 mT) recorded was observed on the hand during a change of coil. It was also observed that the recorded exposure of experienced radiographers working in the MRI environment was less than that of junior staff due to different practices. CONCLUSION This study is of significant importance in Malta since it is the first conducted in a MRI environment, especially because the results were compared with limits imposed by EU Directive 2013/35/EU which has to be implemented by July 2016.
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89
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Budinger TF, Bird MD, Frydman L, Long JR, Mareci TH, Rooney WD, Rosen B, Schenck JF, Schepkin VD, Sherry AD, Sodickson DK, Springer CS, Thulborn KR, Uğurbil K, Wald LL. Toward 20 T magnetic resonance for human brain studies: opportunities for discovery and neuroscience rationale. MAGMA (NEW YORK, N.Y.) 2016; 29:617-39. [PMID: 27194154 PMCID: PMC5538368 DOI: 10.1007/s10334-016-0561-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 12/16/2022]
Abstract
An initiative to design and build magnetic resonance imaging (MRI) and spectroscopy (MRS) instruments at 14 T and beyond to 20 T has been underway since 2012. This initiative has been supported by 22 interested participants from the USA and Europe, of which 15 are authors of this review. Advances in high temperature superconductor materials, advances in cryocooling engineering, prospects for non-persistent mode stable magnets, and experiences gained from large-bore, high-field magnet engineering for the nuclear fusion endeavors support the feasibility of a human brain MRI and MRS system with 1 ppm homogeneity over at least a 16-cm diameter volume and a bore size of 68 cm. Twelve neuroscience opportunities are presented as well as an analysis of the biophysical and physiological effects to be investigated before exposing human subjects to the high fields of 14 T and beyond.
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Affiliation(s)
- Thomas F Budinger
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, USA.
| | - Mark D Bird
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Lucio Frydman
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
- Weizmann Institute, Rehovot, Israel
| | - Joanna R Long
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Thomas H Mareci
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | | | - Bruce Rosen
- Massachusetts General Hospital, Harvard Medical School, Harvard, MA, USA
| | - John F Schenck
- General Electric Corporate Research, Schenectady, NY, USA
| | - Victor D Schepkin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - A Dean Sherry
- University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | | | | | | | - Lawrence L Wald
- Massachusetts General Hospital, Harvard Medical School, Harvard, MA, USA
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90
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Jareonsettasin P, Otero-Millan J, Ward BK, Roberts DC, Schubert MC, Zee DS. Multiple Time Courses of Vestibular Set-Point Adaptation Revealed by Sustained Magnetic Field Stimulation of the Labyrinth. Curr Biol 2016; 26:1359-66. [PMID: 27185559 DOI: 10.1016/j.cub.2016.03.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 11/28/2022]
Abstract
A major focus in neurobiology is how the brain adapts its motor behavior to changes in its internal and external environments [1, 2]. Much is known about adaptively optimizing the amplitude and direction of eye and limb movements, for example, but little is known about another essential form of learning, "set-point" adaptation. Set-point adaptation balances tonic activity so that reciprocally acting, agonist and antagonist muscles have a stable platform from which to launch accurate movements. Here, we use the vestibulo-ocular reflex-a simple behavior that stabilizes the position of the eye while the head is moving-to investigate how tonic activity is adapted toward a new set point to prevent eye drift when the head is still [3, 4]. Set-point adaptation was elicited with magneto-hydrodynamic vestibular stimulation (MVS) by placing normal humans in a 7T MRI for 90 min. MVS is ideal for prolonged labyrinthine activation because it mimics constant head acceleration and induces a sustained nystagmus similar to natural vestibular lesions [5, 6]. The MVS-induced nystagmus diminished slowly but incompletely over multiple timescales. We propose a new adaptation hypothesis, using a cascade of imperfect mathematical integrators, that reproduces the response to MVS (and more natural chair rotations), including the gradual decrease in nystagmus as the set point changes over progressively longer time courses. MVS set-point adaptation is a biological model with applications to basic neurophysiological research into all types of movements [7], functional brain imaging [8], and treatment of vestibular and higher-level attentional disorders by introducing new biases to counteract pathological ones [9].
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Affiliation(s)
- Prem Jareonsettasin
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 1TA, UK
| | - Jorge Otero-Millan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dale C Roberts
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Michael C Schubert
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David S Zee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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91
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High magnetic field induced otolith fusion in the zebrafish larvae. Sci Rep 2016; 6:24151. [PMID: 27063288 PMCID: PMC4827070 DOI: 10.1038/srep24151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 03/21/2016] [Indexed: 01/07/2023] Open
Abstract
Magnetoreception in animals illustrates the interaction of biological systems with the geomagnetic field (geoMF). However, there are few studies that identified the impact of high magnetic field (MF) exposure from Magnetic Resonance Imaging (MRI) scanners (>100,000 times of geoMF) on specific biological targets. Here, we investigated the effects of a 14 Tesla MRI scanner on zebrafish larvae. All zebrafish larvae aligned parallel to the B0 field, i.e. the static MF, in the MRI scanner. The two otoliths (ear stones) in the otic vesicles of zebrafish larvae older than 24 hours post fertilization (hpf) fused together after the high MF exposure as short as 2 hours, yielding a single-otolith phenotype with aberrant swimming behavior. The otolith fusion was blocked in zebrafish larvae under anesthesia or embedded in agarose. Hair cells may play an important role on the MF-induced otolith fusion. This work provided direct evidence to show that high MF interacts with the otic vesicle of zebrafish larvae and causes otolith fusion in an "all-or-none" manner. The MF-induced otolith fusion may facilitate the searching for MF sensors using genetically amenable vertebrate animal models, such as zebrafish.
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92
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Boegle R, Stephan T, Ertl M, Glasauer S, Dieterich M. Magnetic vestibular stimulation modulates default mode network fluctuations. Neuroimage 2016; 127:409-421. [PMID: 26666898 DOI: 10.1016/j.neuroimage.2015.11.065] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 10/22/2022] Open
Abstract
Strong magnetic fields (>1 Tesla) can cause dizziness and it was recently shown that healthy subjects (resting in total darkness) developed a persistent nystagmus even when remaining completely motionless within a MR tomograph. Consequently, it was speculated that this magnetic vestibular stimulation (MVS) might influence fMRI results, as nystagmus is indicative of an imbalance in the vestibular system, potentially influencing other systems via multisensory vestibular interactions. The objective of our study was to investigate whether MVS does indeed modulate BOLD signal fluctuations. We recorded eye movements, as well as, resting-state fMRI of 30 volunteers in darkness at 1.5 T and 3.0 T to answer the question whether MVS modulated parts of the default mode resting-state network (DMN) in accordance with the Lorentz-force model for MVS, while distinguishing this from the known signal increase due to field strength related imaging effects. Our results showed that modulation of the default mode network occurred mainly in areas associated with vestibular and ocular motor function, and was in accordance with the Lorentz-force model, i.e., double than the expected signal scaling due to field strength alone. We discuss the implications of our findings for the interpretation of studies using resting-state fMRI, especially those concerning vestibular research. We conclude that MVS needs to be considered in vestibular research to avoid biased results, but it might also offer the possibility of manipulating network dynamics and may thus help in studying the brain as a dynamical system.
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Affiliation(s)
- Rainer Boegle
- German Center for Vertigo and Balance Disorders (DSGZ-IFB(LMU)), Ludwig-Maximilians-University Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Germany.
| | - Thomas Stephan
- German Center for Vertigo and Balance Disorders (DSGZ-IFB(LMU)), Ludwig-Maximilians-University Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Germany; Department of Neurology, Ludwig-Maximilians-University Munich, Germany
| | - Matthias Ertl
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Germany; Department of Neurology, Ludwig-Maximilians-University Munich, Germany
| | - Stefan Glasauer
- German Center for Vertigo and Balance Disorders (DSGZ-IFB(LMU)), Ludwig-Maximilians-University Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Germany; Center for Sensorimotor Research, Ludwig-Maximilians-University Munich, Germany
| | - Marianne Dieterich
- German Center for Vertigo and Balance Disorders (DSGZ-IFB(LMU)), Ludwig-Maximilians-University Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Germany; Department of Neurology, Ludwig-Maximilians-University Munich, Germany; SyNergy: Cluster for Systems Neurology, Munich, Germany
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93
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Mian OS, Li Y, Antunes A, Glover PM, Day BL. Effect of head pitch and roll orientations on magnetically induced vertigo. J Physiol 2016; 594:1051-67. [PMID: 26614577 PMCID: PMC4753258 DOI: 10.1113/jp271513] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/19/2015] [Indexed: 11/10/2022] Open
Abstract
KEY POINTS Lying supine in a strong magnetic field, such as in magnetic resonance imaging scanners, can induce a perception of whole-body rotation. The leading hypothesis to explain this invokes a Lorentz force mechanism acting on vestibular endolymph that acts to stimulate semicircular canals. The hypothesis predicts that the perception of whole-body rotation will depend on head orientation in the field. Results showed that the direction and magnitude of apparent whole-body rotation while stationary in a 7 T magnetic field is influenced by head orientation. The data are compatible with the Lorentz force hypothesis of magnetic vestibular stimulation and furthermore demonstrate the operation of a spatial transformation process from head-referenced vestibular signals to Earth-referenced body motion. ABSTRACT High strength static magnetic fields are known to induce vertigo, believed to be via stimulation of the vestibular system. The leading hypothesis (Lorentz forces) predicts that the induced vertigo should depend on the orientation of the magnetic field relative to the head. In this study we examined the effect of static head pitch (-80 to +40 deg; 12 participants) and roll (-40 to +40 deg; 11 participants) on qualitative and quantitative aspects of vertigo experienced in the dark by healthy humans when exposed to the static uniform magnetic field inside a 7 T MRI scanner. Three participants were additionally examined at 180 deg pitch and roll orientations. The effect of roll orientation on horizontal and vertical nystagmus was also measured and was found to affect only the vertical component. Vertigo was most discomforting when head pitch was around 60 deg extension and was mildest when it was around 20 deg flexion. Quantitative analysis of vertigo focused on the induced perception of horizontal-plane rotation reported online with the aid of hand-held switches. Head orientation had effects on both the magnitude and the direction of this perceived rotation. The data suggest sinusoidal relationships between head orientation and perception with spatial periods of 180 deg for pitch and 360 deg for roll, which we explain is consistent with the Lorentz force hypothesis. The effects of head pitch on vertigo and previously reported nystagmus are consistent with both effects being driven by a common vestibular signal. To explain all the observed effects, this common signal requires contributions from multiple semicircular canals.
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Affiliation(s)
- Omar S Mian
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
| | - Yan Li
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Andre Antunes
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Paul M Glover
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Brian L Day
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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94
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Indovina I, Riccelli R, Chiarella G, Petrolo C, Augimeri A, Giofrè L, Lacquaniti F, Staab JP, Passamonti L. Role of the Insula and Vestibular System in Patients with Chronic Subjective Dizziness: An fMRI Study Using Sound-Evoked Vestibular Stimulation. Front Behav Neurosci 2015; 9:334. [PMID: 26696853 PMCID: PMC4673311 DOI: 10.3389/fnbeh.2015.00334] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/19/2015] [Indexed: 11/16/2022] Open
Abstract
Chronic subjective dizziness (CSD) is a common vestibular disorder characterized by persistent non-vertiginous dizziness, unsteadiness, and heightened sensitivity to motion stimuli that may last for months to years after events that cause acute vestibular symptoms or disrupt balance. CSD is not associated with abnormalities of basic vestibular or oculomotor reflexes. Rather, it is thought to arise from persistent use of high-threat postural control strategies and greater reliance on visual cues for spatial orientation (i.e., visual dependence), long after triggering events resolve. Anxiety-related personality traits confer vulnerability to CSD. Anomalous interactions between the central vestibular system and neural structures related to anxiety may sustain it. Vestibular- and anxiety-related processes overlap in the brain, particularly in the insula and hippocampus. Alterations in activity and connectivity in these brain regions in response to vestibular stimuli may be the neural basis of CSD. We examined this hypothesis by comparing brain activity from 18 patients with CSD and 18 healthy controls measured by functional magnetic resonance imaging during loud short tone bursts, which are auditory stimuli that evoke robust vestibular responses. Relative to controls, patients with CSD showed reduced activations to sound-evoked vestibular stimulation in the parieto-insular vestibular cortex (PIVC) including the posterior insula, and in the anterior insula, inferior frontal gyrus, hippocampus, and anterior cingulate cortex. Patients with CSD also showed altered connectivity between the anterior insula and PIVC, anterior insula and middle occipital cortex, hippocampus and PIVC, and anterior cingulate cortex and PIVC. We conclude that reduced activation in PIVC, hippocampus, anterior insula, inferior frontal gyrus, and anterior cingulate cortex, as well as connectivity changes among these regions, may be linked to long-term vestibular symptoms in patients with CSD. Furthermore, altered connectivity between the anterior insula and middle occipital cortex may underlie the greater reliance on visual cues for spatial orientation in CSD patients relative to controls.
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Affiliation(s)
- Iole Indovina
- Centre of Space BioMedicine, University of Rome Tor VergataRome, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia FoundationRome, Italy
- *Correspondence: Iole Indovina
| | - Roberta Riccelli
- Department of Medical and Surgical Sciences, University “Magna Graecia,”Catanzaro, Italy
| | - Giuseppe Chiarella
- Department of Experimental and Clinical Medicine, University “Magna Graecia,”Catanzaro, Italy
| | - Claudio Petrolo
- Department of Experimental and Clinical Medicine, University “Magna Graecia,”Catanzaro, Italy
| | - Antonio Augimeri
- Department of Medical and Surgical Sciences, University “Magna Graecia,”Catanzaro, Italy
| | - Laura Giofrè
- Department of Medical and Surgical Sciences, University “Magna Graecia,”Catanzaro, Italy
| | - Francesco Lacquaniti
- Centre of Space BioMedicine, University of Rome Tor VergataRome, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia FoundationRome, Italy
- Department of Systems Medicine, University of Rome Tor VergataRome, Italy
| | - Jeffrey P. Staab
- Department of Psychiatry and Psychology, Mayo ClinicRochester, MN, USA
| | - Luca Passamonti
- Institute of Bioimaging and Molecular Physiology, National Research CouncilCatanzaro, Italy
- Department of Clinical Neurosciences, University of CambridgeCambridge, UK
- Luca Passamonti
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95
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Schaap K, Portengen L, Kromhout H. Exposure to MRI-related magnetic fields and vertigo in MRI workers. Occup Environ Med 2015; 73:161-6. [PMID: 26561507 DOI: 10.1136/oemed-2015-103019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/21/2015] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Vertigo has been reported by people working around magnetic resonance imaging (MRI) scanners and was found to increase with increasing strength of scanner magnets. This suggests an association with exposure to static magnetic fields (SMF) and/or motion-induced time-varying magnetic fields (TVMF). This study assessed the association between various metrics of shift-long exposure to SMF and TVMF and self-reported vertigo among MRI workers. METHODS We analysed 358 shifts from 234 employees at 14 MRI facilities in the Netherlands. Participants used logbooks to report vertigo experienced during the work day at the MRI facility. In addition, personal exposure to SMF and TVMF was measured during the same shifts, using portable magnetic field dosimeters. RESULTS Vertigo was reported during 22 shifts by 20 participants and was significantly associated with peak and time-weighted average (TWA) metrics of SMF as well as TVMF exposure. Associations were most evident with full-shift TWA TVMF exposure. The probability of vertigo occurrence during a work shift exceeded 5% at peak exposure levels of 409 mT and 477 mT/s and at full-shift TWA levels of 3 mT and 0.6 mT/s. CONCLUSIONS These results confirm the hypothesis that vertigo is associated with exposure to MRI-related SMF and TVMF. Strong correlations between various metrics of shift-long exposure make it difficult to disentangle the effects of SMF and TVMF exposure, or identify the most relevant exposure metric. On the other hand, this also implies that several metrics of shift-long exposure to SMF and TVMF should perform similarly in epidemiological studies on MRI-related vertigo.
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Affiliation(s)
- Kristel Schaap
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Lützen Portengen
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Hans Kromhout
- Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
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96
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Francis HW, Papel I, Lina I, Koch W, Tunkel D, Fuchs P, Lin S, Kennedy D, Ruben R, Linthicum F, Marsh B, Best S, Carey J, Lane A, Byrne P, Flint P, Eisele DW. Otolaryngology-head and neck surgery at Johns Hopkins: The first 100 years (1914-2014). Laryngoscope 2015; 125 Suppl 9:S1-35. [PMID: 26297867 PMCID: PMC4696071 DOI: 10.1002/lary.25490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Howard W Francis
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ira Papel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ioan Lina
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Wayne Koch
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Tunkel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Fuchs
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Sandra Lin
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Kennedy
- the Department of Otolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert Ruben
- the Departments ofOtorhinolaryngology-Head and Neck Surgery and Pediatrics, Albert Einstein College of Medicine Montefiore Medical Center, New York, New York
| | - Fred Linthicum
- the Department of Otolaryngology-Head and Neck Surgery, University of California at Los Angeles, Los Angeles, California
| | - Bernard Marsh
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Simon Best
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - John Carey
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Andrew Lane
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Patrick Byrne
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Flint
- Department of Otolaryngology-Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon, U.S.A
| | - David W Eisele
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
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97
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Pfeiffer C, van Elk M, Bernasconi F, Blanke O. Distinct vestibular effects on early and late somatosensory cortical processing in humans. Neuroimage 2015; 125:208-219. [PMID: 26466979 DOI: 10.1016/j.neuroimage.2015.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/31/2015] [Accepted: 10/01/2015] [Indexed: 11/28/2022] Open
Abstract
In non-human primates several brain areas contain neurons that respond to both vestibular and somatosensory stimulation. In humans, vestibular stimulation activates several somatosensory brain regions and improves tactile perception. However, less is known about the spatio-temporal dynamics of such vestibular-somatosensory interactions in the human brain. To address this issue, we recorded high-density electroencephalography during left median nerve electrical stimulation to obtain Somatosensory Evoked Potentials (SEPs). We analyzed SEPs during vestibular activation following sudden decelerations from constant-velocity (90°/s and 60°/s) earth-vertical axis yaw rotations and SEPs during a non-vestibular control period. SEP analysis revealed two distinct temporal effects of vestibular activation: An early effect (28-32ms post-stimulus) characterized by vestibular suppression of SEP response strength that depended on rotation velocity and a later effect (97-112ms post-stimulus) characterized by vestibular modulation of SEP topographical pattern that was rotation velocity-independent. Source estimation localized these vestibular effects, during both time periods, to activation differences in a distributed cortical network including the right postcentral gyrus, right insula, left precuneus, and bilateral secondary somatosensory cortex. These results suggest that vestibular-somatosensory interactions in humans depend on processing in specific time periods in somatosensory and vestibular cortical regions.
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Affiliation(s)
- Christian Pfeiffer
- Laboratoire de Recherche en Neuroimagerie (LREN), Department of Clinical Neuroscience, Lausanne University and University Hospital, Lausanne, Switzerland; Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - Michiel van Elk
- Department of Psychology, University of Amsterdam, Netherlands
| | - Fosco Bernasconi
- Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - Olaf Blanke
- Center for Neuroprosthetics, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; Department of Neurology, University Hospital Geneva, Switzerland.
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98
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99
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Mian OS, Glover PM, Day BL. Reconciling Magnetically Induced Vertigo and Nystagmus. Front Neurol 2015; 6:201. [PMID: 26441821 PMCID: PMC4569971 DOI: 10.3389/fneur.2015.00201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/31/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Omar S Mian
- School of Applied Sciences, London South Bank University , London , UK
| | - Paul M Glover
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham , Nottingham , UK
| | - Brian L Day
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London , London , UK
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100
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Static Magnetic Field Stimulation over the Visual Cortex Increases Alpha Oscillations and Slows Visual Search in Humans. J Neurosci 2015; 35:9182-93. [PMID: 26085640 DOI: 10.1523/jneurosci.4232-14.2015] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transcranial static magnetic field stimulation (tSMS) was recently introduced as a promising tool to modulate human cerebral excitability in a noninvasive and portable way. However, a demonstration that static magnetic fields can influence human brain activity and behavior is currently lacking, despite evidence that static magnetic fields interfere with neuronal function in animals. Here we show that transcranial application of a static magnetic field (120-200 mT at 2-3 cm from the magnet surface) over the human occiput produces a focal increase in the power of alpha oscillations in underlying cortex. Critically, this neurophysiological effect of tSMS is paralleled by slowed performance in a visual search task, selectively for the most difficult target detection trials. The typical relationship between prestimulus alpha power over posterior cortical areas and reaction time (RT) to targets during tSMS is altered such that tSMS-dependent increases in alpha power are associated with longer RTs for difficult, but not easy, target detection trials. Our results directly demonstrate that a powerful magnet placed on the scalp modulates normal brain activity and induces behavioral changes in humans.
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