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TMS Does Not Increase BOLD Activity at the Site of Stimulation: A Review of All Concurrent TMS-fMRI Studies. eNeuro 2022; 9:9/4/ENEURO.0163-22.2022. [PMID: 35981879 PMCID: PMC9410768 DOI: 10.1523/eneuro.0163-22.2022] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/14/2022] [Accepted: 06/30/2022] [Indexed: 11/21/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is widely used for understanding brain function in neurologically intact subjects and for the treatment of various disorders. However, the precise neurophysiological effects of TMS at the site of stimulation remain poorly understood. The local effects of TMS can be studied using concurrent TMS-functional magnetic resonance imaging (fMRI), a technique where TMS is delivered during fMRI scanning. However, although concurrent TMS-fMRI was developed over 20 years ago and dozens of studies have used this technique, there is still no consensus on whether TMS increases blood oxygen level-dependent (BOLD) activity at the site of stimulation. To address this question, here we review all previous concurrent TMS-fMRI studies that reported analyses of BOLD activity at the target location. We find evidence that TMS increases local BOLD activity when stimulating the primary motor (M1) and visual (V1) cortices but that these effects are likely driven by the downstream consequences of TMS (finger twitches and phosphenes). However, TMS does not appear to increase BOLD activity at the site of stimulation for areas outside of the M1 and V1 when conducted at rest. We examine the possible reasons for such lack of BOLD signal increase based on recent work in nonhuman animals. We argue that the current evidence points to TMS inducing periods of increased and decreased neuronal firing that mostly cancel each other out and therefore lead to no change in the overall BOLD signal.
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Mizutani-Tiebel Y, Tik M, Chang KY, Padberg F, Soldini A, Wilkinson Z, Voon CC, Bulubas L, Windischberger C, Keeser D. Concurrent TMS-fMRI: Technical Challenges, Developments, and Overview of Previous Studies. Front Psychiatry 2022; 13:825205. [PMID: 35530029 PMCID: PMC9069063 DOI: 10.3389/fpsyt.2022.825205] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is a promising treatment modality for psychiatric and neurological disorders. Repetitive TMS (rTMS) is widely used for the treatment of psychiatric and neurological diseases, such as depression, motor stroke, and neuropathic pain. However, the underlying mechanisms of rTMS-mediated neuronal modulation are not fully understood. In this respect, concurrent or simultaneous TMS-fMRI, in which TMS is applied during functional magnetic resonance imaging (fMRI), is a viable tool to gain insights, as it enables an investigation of the immediate effects of TMS. Concurrent application of TMS during neuroimaging usually causes severe artifacts due to magnetic field inhomogeneities induced by TMS. However, by carefully interleaving the TMS pulses with MR signal acquisition in the way that these are far enough apart, we can avoid any image distortions. While the very first feasibility studies date back to the 1990s, recent developments in coil hardware and acquisition techniques have boosted the number of TMS-fMRI applications. As such, a concurrent application requires expertise in both TMS and MRI mechanisms and sequencing, and the hurdle of initial technical set up and maintenance remains high. This review gives a comprehensive overview of concurrent TMS-fMRI techniques by collecting (1) basic information, (2) technical challenges and developments, (3) an overview of findings reported so far using concurrent TMS-fMRI, and (4) current limitations and our suggestions for improvement. By sharing this review, we hope to attract the interest of researchers from various backgrounds and create an educational knowledge base.
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Affiliation(s)
- Yuki Mizutani-Tiebel
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany
| | - Martin Tik
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Kai-Yen Chang
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany
| | - Frank Padberg
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany
| | - Aldo Soldini
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany.,International Max Planck Research School for Translational Psychiatry, Munich, Germany
| | - Zane Wilkinson
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany
| | - Cui Ci Voon
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany
| | - Lucia Bulubas
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany.,International Max Planck Research School for Translational Psychiatry, Munich, Germany
| | - Christian Windischberger
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Daniel Keeser
- Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany.,Neuroimaging Core Unit Munich - NICUM, University Hospital LMU, Munich, Germany.,Department of Radiology, University Hospital LMU, Munich, Germany
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Bergmann TO, Varatheeswaran R, Hanlon CA, Madsen KH, Thielscher A, Siebner HR. Concurrent TMS-fMRI for causal network perturbation and proof of target engagement. Neuroimage 2021; 237:118093. [PMID: 33940146 DOI: 10.1016/j.neuroimage.2021.118093] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/06/2021] [Accepted: 04/14/2021] [Indexed: 12/12/2022] Open
Abstract
The experimental manipulation of neural activity by neurostimulation techniques overcomes the inherent limitations of correlative recordings, enabling the researcher to investigate causal brain-behavior relationships. But only when stimulation and recordings are combined, the direct impact of the stimulation on neural activity can be evaluated. In humans, this can be achieved non-invasively through the concurrent combination of transcranial magnetic stimulation (TMS) with functional magnetic resonance imaging (fMRI). Concurrent TMS-fMRI allows the assessment of the neurovascular responses evoked by TMS with excellent spatial resolution and full-brain coverage. This enables the functional mapping of both local and remote network effects of TMS in cortical as well as deep subcortical structures, offering unique opportunities for basic research and clinical applications. The purpose of this review is to introduce the reader to this powerful tool. We will introduce the technical challenges and state-of-the art solutions and provide a comprehensive overview of the existing literature and the available experimental approaches. We will highlight the unique insights that can be gained from concurrent TMS-fMRI, including the state-dependent assessment of neural responsiveness and inter-regional effective connectivity, the demonstration of functional target engagement, and the systematic evaluation of stimulation parameters. We will also discuss how concurrent TMS-fMRI during a behavioral task can help to link behavioral TMS effects to changes in neural network activity and to identify peripheral co-stimulation confounds. Finally, we will review the use of concurrent TMS-fMRI for developing TMS treatments of psychiatric and neurological disorders and suggest future improvements for further advancing the application of concurrent TMS-fMRI.
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Affiliation(s)
- Til Ole Bergmann
- Neuroimaging Center (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131, Mainz, Germany; Leibniz Institute for Resilience Research, Wallstraße 7-9, 55122, Mainz, Germany.
| | - Rathiga Varatheeswaran
- Neuroimaging Center (NIC), Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University Medical Center, Langenbeckstr. 1, 55131, Mainz, Germany; Leibniz Institute for Resilience Research, Wallstraße 7-9, 55122, Mainz, Germany
| | - Colleen A Hanlon
- Department of Cancer Biology, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157, USA
| | - Kristoffer H Madsen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, 2650, Hvidovre, Denmark; Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, 2650, Hvidovre, Denmark; Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, 2650, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400 København NV, Denmark; Department of Clinical Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
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EPI distortion correction for concurrent human brain stimulation and imaging at 3T. J Neurosci Methods 2019; 327:108400. [PMID: 31434000 DOI: 10.1016/j.jneumeth.2019.108400] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 01/21/2023]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) can be paired with functional magnetic resonance imaging (fMRI) in concurrent TMS-fMRI experiments. These multimodal experiments enable causal probing of network architecture in the human brain which can complement alternative network mapping approaches. Critically, merely introducing the TMS coil into the scanner environment can sometimes produce substantial magnetic field inhomogeneities and spatial distortions which limit the utility of concurrent TMS-fMRI. METHOD AND RESULTS We assessed the efficacy of point spread function corrected echo planar imaging (PSF-EPI) in correcting for the field inhomogeneities associated with a TMS coil at 3 T. In phantom and brain scans, we quantitatively compared the coil-induced distortion artifacts measured in EPI scans with and without PSF correction. We found that the application of PSF corrections to the EPI data significantly improved signal-to-noise and reduced distortions. In phantom scans with the PSF-EPI sequence, we also characterized the temporal profile of dynamic artifacts associated with TMS delivery and found that image quality remained high as long as the TMS pulse preceded the RF excitation pulses by at least 50 ms. Lastly, we validated the PSF-EPI sequence in human brain scans involving TMS and motor behavior as well as resting state fMRI scans. CONCLUSIONS Our collective results demonstrate the potential benefits of PSF-EPI for concurrent TMS-fMRI when coil-related artifacts are a concern. The ability to collect high quality resting state fMRI data in the same session as the concurrent TMS-fMRI experiment offers a unique opportunity to interrogate network architecture in the human brain.
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Yau JM, DeAngelis GC, Angelaki DE. Dissecting neural circuits for multisensory integration and crossmodal processing. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140203. [PMID: 26240418 DOI: 10.1098/rstb.2014.0203] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We rely on rich and complex sensory information to perceive and understand our environment. Our multisensory experience of the world depends on the brain's remarkable ability to combine signals across sensory systems. Behavioural, neurophysiological and neuroimaging experiments have established principles of multisensory integration and candidate neural mechanisms. Here we review how targeted manipulation of neural activity using invasive and non-invasive neuromodulation techniques have advanced our understanding of multisensory processing. Neuromodulation studies have provided detailed characterizations of brain networks causally involved in multisensory integration. Despite substantial progress, important questions regarding multisensory networks remain unanswered. Critically, experimental approaches will need to be combined with theory in order to understand how distributed activity across multisensory networks collectively supports perception.
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Affiliation(s)
- Jeffrey M Yau
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gregory C DeAngelis
- Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA
| | - Dora E Angelaki
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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Navarro de Lara LI, Windischberger C, Kuehne A, Woletz M, Sieg J, Bestmann S, Weiskopf N, Strasser B, Moser E, Laistler E. A novel coil array for combined TMS/fMRI experiments at 3 T. Magn Reson Med 2014; 74:1492-501. [PMID: 25421603 PMCID: PMC4737243 DOI: 10.1002/mrm.25535] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 11/22/2022]
Abstract
Purpose To overcome current limitations in combined transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) studies by employing a dedicated coil array design for 3 Tesla. Methods The state‐of‐the‐art setup for concurrent TMS/fMRI is to use a large birdcage head coil, with the TMS between the subject's head and the MR coil. This setup has drawbacks in sensitivity, positioning, and available imaging techniques. In this study, an ultraslim 7‐channel receive‐only coil array for 3 T, which can be placed between the subject's head and the TMS, is presented. Interactions between the devices are investigated and the performance of the new setup is evaluated in comparison to the state‐of‐the‐art setup. Results MR sensitivity obtained at the depth of the TMS stimulation is increased by a factor of five. Parallel imaging with an acceleration factor of two is feasible with low g‐factors. Possible interactions between TMS and the novel hardware were investigated and were found negligible. Conclusion The novel coil array is safe, strongly improves signal‐to‐noise ratio in concurrent TMS/fMRI experiments, enables parallel imaging, and allows for flexible positioning of the TMS on the head while ensuring efficient TMS stimulation due to its ultraslim design. Magn Reson Med 74:1492–1501, 2015. © 2014 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Lucia I Navarro de Lara
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Christian Windischberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Andre Kuehne
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Michael Woletz
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Jürgen Sieg
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Sven Bestmann
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London, United Kingdom
| | - Nikolaus Weiskopf
- Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom
| | - Bernhard Strasser
- MR Centre of Excellence, Medical University of Vienna, Vienna, Austria.,Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
| | - Elmar Laistler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,MR Centre of Excellence, Medical University of Vienna, Vienna, Austria
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Liao DA, Kronemer SI, Yau JM, Desmond JE, Marvel CL. Motor system contributions to verbal and non-verbal working memory. Front Hum Neurosci 2014; 8:753. [PMID: 25309402 PMCID: PMC4173669 DOI: 10.3389/fnhum.2014.00753] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/07/2014] [Indexed: 11/28/2022] Open
Abstract
Working memory (WM) involves the ability to maintain and manipulate information held in mind. Neuroimaging studies have shown that secondary motor areas activate during WM for verbal content (e.g., words or letters), in the absence of primary motor area activation. This activation pattern may reflect an inner speech mechanism supporting online phonological rehearsal. Here, we examined the causal relationship between motor system activity and WM processing by using transcranial magnetic stimulation (TMS) to manipulate motor system activity during WM rehearsal. We tested WM performance for verbalizable (words and pseudowords) and non-verbalizable (Chinese characters) visual information. We predicted that disruption of motor circuits would specifically affect WM processing of verbalizable information. We found that TMS targeting motor cortex slowed response times (RTs) on verbal WM trials with high (pseudoword) vs. low (real word) phonological load. However, non-verbal WM trials were also significantly slowed with motor TMS. WM performance was unaffected by sham stimulation or TMS over visual cortex (VC). Self-reported use of motor strategy predicted the degree of motor stimulation disruption on WM performance. These results provide evidence of the motor system’s contributions to verbal and non-verbal WM processing. We speculate that the motor system supports WM by creating motor traces consistent with the type of information being rehearsed during maintenance.
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Affiliation(s)
- Diana A Liao
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Neuroscience Institute, Princeton University Princeton, NJ, USA
| | - Sharif I Kronemer
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Jeffrey M Yau
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Neuroscience, Baylor College of Medicine Houston, TX, USA
| | - John E Desmond
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Cherie L Marvel
- Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine Baltimore, MD, USA
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Yau JM, Jalinous R, Cantarero GL, Desmond JE. Static field influences on transcranial magnetic stimulation: considerations for TMS in the scanner environment. Brain Stimul 2014; 7:388-93. [PMID: 24656916 DOI: 10.1016/j.brs.2014.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 01/17/2014] [Accepted: 02/14/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) can be combined with functional magnetic resonance imaging (fMRI) to simultaneously manipulate and monitor human cortical responses. Although tremendous efforts have been directed at characterizing the impact of TMS on image acquisition, the influence of the scanner's static field on the TMS coil has received limited attention. OBJECTIVE/HYPOTHESIS The aim of this study was to characterize the influence of the scanner's static field on TMS. We hypothesized that spatial variations in the static field could account for TMS field variations in the scanner environment. METHODS Using an MRI-compatible TMS coil, we estimated TMS field strengths based on TMS-induced voltage changes measured in a search coil. We compared peak field strengths obtained with the TMS coil positioned at different locations (B0 field vs fringe field) and orientations in the static field. We also measured the scanner's static field to derive a field map to account for TMS field variations. RESULTS TMS field strength scaled depending on coil location and orientation with respect to the static field. Larger TMS field variations were observed in fringe field regions near the gantry as compared to regions inside the bore or further removed from the bore. The scanner's static field also exhibited the greatest spatial variations in fringe field regions near the gantry. CONCLUSIONS The scanner's static field influences TMS fields and spatial variations in the static field correlate with TMS field variations. Coil orientation changes in the B0 field did not result in substantial TMS field variations. TMS field variations can be minimized by delivering TMS in the bore or outside of the 0-70 cm region from the bore entrance.
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Affiliation(s)
- Jeffrey M Yau
- Department of Neurology, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
| | | | - Gabriela L Cantarero
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA; Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA
| | - John E Desmond
- Department of Neurology, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA
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