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de Albuquerque LL, Pantovic M, Wilkins EW, Morris D, Clingo M, Boss S, Riley ZA, Poston B. Exploring the Influence of Inter-Trial Interval on the Assessment of Short-Interval Intracortical Inhibition. Bioengineering (Basel) 2024; 11:645. [PMID: 39061727 PMCID: PMC11274151 DOI: 10.3390/bioengineering11070645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/05/2024] [Accepted: 06/17/2024] [Indexed: 07/28/2024] Open
Abstract
Short-interval intracortical inhibition (SICI) is a common paired-pulse transcranial magnetic stimulation (TMS) measure used to assess primary motor cortex (M1) interneuron activity in healthy populations and in neurological disorders. Many of the parameters of TMS stimulation to most accurately measure SICI have been determined. However, one TMS parameter that has not been investigated is the time between SICI trials (termed inter-trial interval; ITI). This is despite a series of single-pulse TMS studies which have reported that motor evoked potential (MEP) amplitude were suppressed for short, but not long ITIs in approximately the initial ten trials of a TMS block of 20-30 trials. The primary purpose was to examine the effects of ITI on the quantification of SICI at rest. A total of 23 healthy adults completed an experimental session that included four SICI trial blocks. Each block utilized a different ITI (4, 6, 8, and 10 s) and was comprised of a total of 26 SICI trials divided into three epochs. ANOVA revealed that the main effects for ITI and epoch as well as their interaction were all non-statistically significant for SICI. We conclude that the shorter (4-6 s) ITIs used in studies investigating SICI should not alter the interpretation of M1 activity, while having the advantages of being more comfortable to participants and reducing the experimental time needed to evaluate perform single and paired-pulse TMS experiments.
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Affiliation(s)
- Lidio Lima de Albuquerque
- School of Health and Applied Human Sciences, University of North Carolina Wilmington, Wilmington, NC 28403, USA;
| | - Milan Pantovic
- Health and Human Performance Department, Utah Tech University, St. George, UT 84770, USA;
| | - Erik W. Wilkins
- Department of Kinesiology and Nutrition Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA;
| | - Desiree Morris
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (D.M.); (M.C.)
| | - Mitchell Clingo
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (D.M.); (M.C.)
| | - Sage Boss
- School of Life Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
| | - Zachary A. Riley
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA;
| | - Brach Poston
- Department of Kinesiology and Nutrition Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA;
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Prei K, Kanig C, Osnabruegge M, Langguth B, Mack W, Abdelnaim M, Schecklmann M, Schoisswohl S. Limited evidence for reliability of low and high frequency rTMS over the motor cortex. Brain Res 2023; 1820:148534. [PMID: 37586677 DOI: 10.1016/j.brainres.2023.148534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/07/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the reliability of low-frequency and high-frequency repetitive transcranial magnetic stimulation (rTMS) on healthy individuals over the motor cortex. A secondary outcome was the assessment if low-frequency rTMS results in inhibition and high-frequency rTMS results in facilitation. METHODS In this experiment, 30 healthy participants received on four consecutive days one session each with application of 1 Hz or 20 Hz rTMS over the left motor cortex. 1 Hz and 20 Hz were applied in alternating order, whereby the starting frequency was randomized. Motor evoked potentials (MEPs) were measured before and after each session. Reliability measures were intraclass and Pearson's correlation coefficient (ICC and r). RESULTS ICCs and r values were low to moderate. Notably, within subgroups of less confounded measures, we found good r values for 20 Hz rTMS. The group-level analysis did not demonstrate a clear low-frequency inhibition and high-frequency facilitation pattern. At the single-subject level, only one participant exhibited significant changes consistent with the expected pattern, with concurrent decreases in MEPs following 1 Hz sessions and increases following 20 Hz sessions. CONCLUSION The investigated neuromodulatory protocols show low to moderate reliability. Results are questioning the low-frequency inhibition and high-frequency facilitation pattern. SIGNIFICANCE Methodological improvements for the usage of rTMS are necessary to increase validity and reliability of non-invasive brain stimulation.
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Affiliation(s)
- Kilian Prei
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Carolina Kanig
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany.
| | - Mirja Osnabruegge
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
| | - Berthold Langguth
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Wolfgang Mack
- Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
| | - Mohamed Abdelnaim
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Martin Schecklmann
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany
| | - Stefan Schoisswohl
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93053 Regensburg, Germany; Department of Human Sciences, University of the Bundeswehr Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
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3
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Pantovic M, Boss R, Noorda KJ, Premyanov MI, Aynlender DG, Wilkins EW, Boss S, Riley ZA, Poston B. The Influence of Different Inter-Trial Intervals on the Quantification of Intracortical Facilitation in the Primary Motor Cortex. Bioengineering (Basel) 2023; 10:1278. [PMID: 38002401 PMCID: PMC10669180 DOI: 10.3390/bioengineering10111278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/29/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
Intracortical facilitation (ICF) is a paired-pulse transcranial magnetic stimulation (TMS) measurement used to quantify interneuron activity in the primary motor cortex (M1) in healthy populations and motor disorders. Due to the prevalence of the technique, most of the stimulation parameters to optimize ICF quantification have been established. However, the underappreciated methodological issue of the time between ICF trials (inter-trial interval; ITI) has been unstandardized, and different ITIs have never been compared in a paired-pulse TMS study. This is important because single-pulse TMS studies have found motor evoked potential (MEP) amplitude reductions over time during TMS trial blocks for short, but not long ITIs. The primary purpose was to determine the influence of different ITIs on the measurement of ICF. Twenty adults completed one experimental session that involved 4 separate ICF trial blocks with each utilizing a different ITI (4, 6, 8, and 10 s). Two-way ANOVAs indicated no significant ITI main effects for test MEP amplitudes, condition-test MEP amplitudes, and therefore ICF. Accordingly, all ITIs studied provided nearly identical ICF values when averaged over entire trial blocks. Therefore, it is recommended that ITIs of 4-6 s be utilized for ICF quantification to optimize participant comfort and experiment time efficiency.
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Affiliation(s)
- Milan Pantovic
- Health and Human Performance Department, Utah Tech University, St. George, UT 84770, USA;
| | - Rhett Boss
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (R.B.); (K.J.N.); (M.I.P.); (D.G.A.)
| | - Kevin J. Noorda
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (R.B.); (K.J.N.); (M.I.P.); (D.G.A.)
| | - Mario I. Premyanov
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (R.B.); (K.J.N.); (M.I.P.); (D.G.A.)
| | - Daniel G. Aynlender
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (R.B.); (K.J.N.); (M.I.P.); (D.G.A.)
| | - Erik W. Wilkins
- Department of Kinesiology and Nutrition Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
| | - Sage Boss
- School of Life Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
| | - Zachary A. Riley
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA;
| | - Brach Poston
- Department of Kinesiology and Nutrition Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
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Knowles KS, Beausejour JP, Harmon KK, Girts RM, Fukuda DH, Kidgell DJ, Stock MS. The Influence of Transcranial Magnetic Stimulation Interpulse Interval Duration on Knee Extensor Corticospinal Excitability. Brain Connect 2023; 13:521-527. [PMID: 37522578 DOI: 10.1089/brain.2023.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023] Open
Abstract
Background/Purpose: To examine the influence of interpulse interval duration on knee extensor corticospinal excitability. Methods: Seventeen college-aged males and females participated in a single laboratory visit, during which 25 single transcranial magnetic stimulation pulses were delivered to the motor cortex with interpulse intervals of 5, 10, 15, and 20 sec. Surface electromyographic signals were detected from the dominant vastus lateralis and rectus femoris. Motor evoked potential amplitude was compared across the four conditions. Results: For the vastus lateralis, the Friedman test indicated significant differences among conditions (chi-squared [3] = 7.80, p = 0.050); however, there were no pairwise differences (p ≥ 0.094) and small effect sizes (d ≤ 0.269). For the rectus femoris, the Friedman test results showed no significant differences among conditions (chi-squared [3] = 2.44, p = 0.487). Across all muscles and conditions, low intraclass correlation coefficients and high standard errors of measurement were suggestive of poor reliability. Conclusion: Unlike resting hand muscles, interpulse interval duration has little influence on corticospinal excitability for the knee extensors during active contractions.
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Affiliation(s)
- Kevan S Knowles
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida, USA
| | - Jonathan P Beausejour
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida, USA
| | - Kylie K Harmon
- David B. Falk College of Sport and Human Dynamics, Syracuse University, Syracuse, New York, USA
| | - Ryan M Girts
- Department of Natural and Health Sciences, Pfeiffer University, Misenheimer, North Carolina, USA
| | - David H Fukuda
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida, USA
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, School of Primary and Allied Healthcare, Monash University, Melbourne, Australia
| | - Matt S Stock
- Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, Florida, USA
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Grimm K, Prilop L, Schön G, Gelderblom M, Misselhorn J, Gerloff C, Zittel S. Cerebellar Modulation of Sensorimotor Associative Plasticity Is Impaired in Cervical Dystonia. Mov Disord 2023; 38:2084-2093. [PMID: 37641392 DOI: 10.1002/mds.29586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/28/2023] [Accepted: 08/04/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND In recent years, cervical dystonia (CD) has been recognized as a network disorder that involves not only the basal ganglia but other brain regions, such as the primary motor and somatosensory cortex, brainstem, and cerebellum. So far, the role of the cerebellum in the pathophysiology of dystonia is only poorly understood. OBJECTIVE The objective of this study was to investigate the role of the cerebellum on sensorimotor associative plasticity in patients with CD. METHODS Sixteen patients with CD and 13 healthy subjects received cerebellar transcranial direct current stimulation (ctDCS) followed by a paired associative stimulation (PAS) protocol based on transcranial magnetic stimulation that induces sensorimotor associative plasticity. Across three sessions the participants received excitatory anodal, inhibitory cathodal, and sham ctDCS in a double-blind crossover design. Before and after the intervention, motor cortical excitability and motor symptom severity were assessed. RESULTS PAS induced an increase in motor cortical excitability in both healthy control subjects and patients with CD. In healthy subjects this effect was attenuated by both anodal and cathodal ctDCS with a stronger effect of cathodal stimulation. In patients with CD, anodal stimulation suppressed the PAS effect, whereas cathodal stimulation had no influence on PAS. Motor symptom severity was unchanged after the intervention. CONCLUSIONS Cerebellar modulation with cathodal ctDCS had no effect on sensorimotor associative plasticity in patients with CD, in contrast with the net inhibitory effect in healthy subjects. This is further evidence that the cerebello-thalamo-cortical network plays a role in the pathophysiology of dystonia. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Kai Grimm
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lisa Prilop
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerhard Schön
- Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mathias Gelderblom
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jonas Misselhorn
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Gerloff
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Simone Zittel
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Spampinato DA, Ibanez J, Rocchi L, Rothwell J. Motor potentials evoked by transcranial magnetic stimulation: interpreting a simple measure of a complex system. J Physiol 2023; 601:2827-2851. [PMID: 37254441 PMCID: PMC10952180 DOI: 10.1113/jp281885] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 05/18/2023] [Indexed: 06/01/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive technique that is increasingly used to study the human brain. One of the principal outcome measures is the motor-evoked potential (MEP) elicited in a muscle following TMS over the primary motor cortex (M1), where it is used to estimate changes in corticospinal excitability. However, multiple elements play a role in MEP generation, so even apparently simple measures such as peak-to-peak amplitude have a complex interpretation. Here, we summarize what is currently known regarding the neural pathways and circuits that contribute to the MEP and discuss the factors that should be considered when interpreting MEP amplitude measured at rest in the context of motor processing and patients with neurological conditions. In the last part of this work, we also discuss how emerging technological approaches can be combined with TMS to improve our understanding of neural substrates that can influence MEPs. Overall, this review aims to highlight the capabilities and limitations of TMS that are important to recognize when attempting to disentangle sources that contribute to the physiological state-related changes in corticomotor excitability.
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Affiliation(s)
- Danny Adrian Spampinato
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- Department of Human NeurosciencesSapienza University of RomeRomeItaly
- Department of Clinical and Behavioral NeurologyIRCCS Santa Lucia FoundationRomeItaly
| | - Jaime Ibanez
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- BSICoS group, I3A Institute and IIS AragónUniversity of ZaragozaZaragozaSpain
- Department of Bioengineering, Centre for NeurotechnologiesImperial College LondonLondonUK
| | - Lorenzo Rocchi
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- Department of Medical Sciences and Public HealthUniversity of CagliariCagliariItaly
| | - John Rothwell
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
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7
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Weise K, Numssen O, Kalloch B, Zier AL, Thielscher A, Haueisen J, Hartwigsen G, Knösche TR. Precise motor mapping with transcranial magnetic stimulation. Nat Protoc 2023; 18:293-318. [PMID: 36460808 DOI: 10.1038/s41596-022-00776-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 08/17/2022] [Indexed: 12/03/2022]
Abstract
We describe a routine to precisely localize cortical muscle representations within the primary motor cortex with transcranial magnetic stimulation (TMS) based on the functional relation between induced electric fields at the cortical level and peripheral muscle activation (motor-evoked potentials; MEPs). Besides providing insights into structure-function relationships, this routine lays the foundation for TMS dosing metrics based on subject-specific cortical electric field thresholds. MEPs for different coil positions and orientations are combined with electric field modeling, exploiting the causal nature of neuronal activation to pinpoint the cortical origin of the MEPs. This involves constructing an individual head model using magnetic resonance imaging, recording MEPs via electromyography during TMS and computing the induced electric fields with numerical modeling. The cortical muscle representations are determined by relating the TMS-induced electric fields to the MEP amplitudes. Subsequently, the coil position to optimally stimulate the origin of the identified cortical MEP can be determined by numerical modeling. The protocol requires 2 h of manual preparation, 10 h for the automated head model construction, one TMS session lasting 2 h, 12 h of computational postprocessing and an optional second TMS session lasting 30 min. A basic level of computer science expertise and standard TMS neuronavigation equipment suffices to perform the protocol.
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Affiliation(s)
- Konstantin Weise
- Methods and Development Group 'Brain Networks', Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. .,Technische Universität Ilmenau, Advanced Electromagnetics Group, Ilmenau, Germany.
| | - Ole Numssen
- Lise Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Benjamin Kalloch
- Methods and Development Group 'Brain Networks', Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Ilmenau, Germany
| | - Anna Leah Zier
- Institute of Medical Psychology, Medical Faculty, Goethe-University, Frankfurt/Main, Germany
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager and Hvidovre, Hvidovre, Denmark.,Technical University of Denmark, Center for Magnetic Resonance, Department of Health Technology, Kongens Lyngby, Denmark
| | - Jens Haueisen
- Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Ilmenau, Germany
| | - Gesa Hartwigsen
- Lise Meitner Research Group Cognition and Plasticity, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Thomas R Knösche
- Methods and Development Group 'Brain Networks', Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.,Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Ilmenau, Germany
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8
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The effects of concurrent bilateral anodal tDCS of primary motor cortex and cerebellum on corticospinal excitability: a randomized, double-blind sham-controlled study. Brain Struct Funct 2022; 227:2395-2408. [PMID: 35984496 PMCID: PMC9418272 DOI: 10.1007/s00429-022-02533-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 06/30/2022] [Indexed: 11/11/2022]
Abstract
Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1), and cerebellum (CB) can change the level of M1 corticospinal excitability (CSE). A randomized double-blinded crossover, the sham-controlled study design was used to investigate the effects of concurrent bilateral anodal tDCS of M1 and CB (concurrent bilateral a-tDCSM1+CB) on the CSE. Twenty-one healthy participants were recruited in this study. Each participant received anodal-tDCS (a-tDCS) of 2 mA, 20 min in four pseudo-randomized, counterbalanced sessions, separated by at least 7 days (7.11 days ± 0.65). These sessions were bilateral M1 stimulation (bilateral a-tDCSM1), bilateral cerebellar stimulation (bilateral a-tDCSCB), concurrent bilateral a-tDCSM1+CB, and sham stimulation (bilateral a-tDCSSham). Transcranial magnetic stimulation (TMS) was delivered over the left M1, and motor evoked potentials (MEPs) of a contralateral hand muscle were recorded before and immediately after the intervention to measure CSE changes. Short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long interval intracortical inhibition (LICI) were assessed with paired-pulse TMS protocols. Anodal-tDCS significantly increased CSE after concurrent bilateral a-tDCSM1+CB and bilateral a-tDCSCB. Interestingly, CSE was decreased after bilateral a-tDCSM1. Respective alterations in SICI, LICI, and ICF were seen, including increased SICI and decreased ICF, which indicate the involvement of glutamatergic and GABAergic systems in these effects. These results confirm that the concurrent bilateral a-tDCSM1+CB have a facilitatory effect on CSE, whereas bilateral a-tDCSM1 exert some inhibitory effects. Moreover, the effects of the 2 mA, 20 min a-tDCS on the CB were consistent with its effects on the M1.
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Kallioniemi E, Awiszus F, Pitkänen M, Julkunen P. Fast acquisition of resting motor threshold with a stimulus-response curve - Possibility or hazard for transcranial magnetic stimulation applications? Clin Neurophysiol Pract 2022; 7:7-15. [PMID: 35024510 PMCID: PMC8733273 DOI: 10.1016/j.cnp.2021.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 09/15/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022] Open
Abstract
Objective Previous research has suggested that transcranial magnetic stimulation (TMS) related cortical excitability measures could be estimated quickly using stimulus-response curves with short interstimulus intervals (ISIs). Here we evaluated the resting motor threshold (rMT) estimated with these curves. Methods Stimulus-response curves were measured with three ISIs: 1.2-2 s, 2-3 s, and 3-4 s. Each curve was formed with 108 stimuli using stimulation intensities ranging from 0.75 to 1.25 times the rMTguess, which was estimated based on motor evoked potential (MEP) amplitudes of three scout responses. Results The ISI did not affect the rMT estimated from the curves (F = 0.235, p = 0.683) or single-trial MEP amplitudes at the group level (F = 0.90, p = 0.405), but a significant subject by ISI interaction (F = 3.64; p < 0.001) was detected in MEP amplitudes. No trend was observed which ISI was most excitable, as it varied between subjects. Conclusions At the group level, the stimulus-response curves are unaffected by the short ISI. At the individual level, these curves are highly affected by the ISI. Significance Estimating rMT using stimulus-response curves with short ISIs impacts the rMT estimate and should be avoided in clinical and research TMS applications.
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Key Words
- APB, abductor pollicis brevis
- EMG, electromyography
- ISI, interstimulus interval
- Interstimulus interval
- MEP, motor evoked potential
- MRI, magnetic resonance imaging
- MSO, maximum stimulator output
- Motor evoked potential
- Motor threshold
- SI, stimulation intensity
- Stimulus-response curve
- TMS, transcranial magnetic stimulation
- rMT, resting motor threshold
- rMTRR, resting motor threshold estimated with the Rossini-Rothwell method
- rMTestimate, resting motor threshold estimated with stimulus–response curves
- rMTguess, resting motor threshold estimated with prior information and three scout pulses
- rMTthreshold, resting motor threshold estimated with the threshold-hunting method
- rMTtrue, true resting motor threshold in simulations
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Affiliation(s)
- Elisa Kallioniemi
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, United States
| | - Friedemann Awiszus
- Neuromuscular Research Group at the Department of Orthopaedics, Otto-von-Guericke University, Magdeburg, Germany
| | - Minna Pitkänen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Petro Julkunen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
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10
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Bekkali S, Youssef GJ, Donaldson PH, Hyde C, Do M, He JL, Barhoun P, Enticott PG. Is there a relationship between EEG and sTMS neurophysiological markers of the putative human mirror neuron system? J Neurosci Res 2021; 99:3238-3249. [PMID: 34747052 DOI: 10.1002/jnr.24969] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 11/08/2022]
Abstract
The mirror neuron system (MNS) has been theorized to play a neurobiological role in a number of social cognitive abilities and is commonly indexed putatively in humans via interpersonal motor resonance (IMR) and mu suppression. Although both indices are thought to measure similar neuronal populations (i.e., "mirror neurons"), it has been suggested that these methods are unrelated, and therefore, incompatible. However, prior studies reporting no relationships were typically conducted in small and underpowered samples. Thus, we aimed to investigate this potential association in a large sample of neurotypical adults (N = 116; 72 females). Participants underwent transcranial magnetic stimulation (TMS), electromyography (EMG), and electroencephalography (EEG) during the observation of videos of actors performing grasping actions in order to index IMR and mu suppression (in beta, lower alpha, and upper alpha bandwidths). A series of linear regressions revealed no associations between IMR and each of the mu suppression bandwidths. Supplementary Bayesian analyses provided further evidence in favor of the null (B01 = 8.85-8.93), providing further support for no association between the two indices of MNS activity. Our findings suggest that these two measures may indeed be unrelated indices that perhaps assess different neurophysiological aspects of the MNS. These results have important implications for future studies examining the MNS.
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Affiliation(s)
- Soukayna Bekkali
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
| | - George J Youssef
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia.,Centre for Adolescent Health, Murdoch Children's Research Institute, Parkville, Melbourne, VIC, Australia
| | - Peter H Donaldson
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
| | - Christian Hyde
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
| | - Michael Do
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
| | - Jason L He
- Department of Forensic and Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Pamela Barhoun
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
| | - Peter G Enticott
- Cognitive Neuroscience Unit (CNU), School of Psychology, Deakin University, Burwood, VIC, Australia
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11
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Roumengous T, Reutter AB, Peterson CL. Effect of low-cost transcranial magnetic stimulation navigation on hotspot targeting and motor evoked potential variability in the biceps brachii. Restor Neurol Neurosci 2021; 39:319-328. [PMID: 34657854 DOI: 10.3233/rnn-211207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) can monitor or modulate brain excitability. However, reliability of TMS outcomes depends on consistent coil placement during stimulation. Neuronavigated TMS systems can address this issue, but their cost limits their use outside of specialist research environments. OBJECTIVE The objective was to evaluate the performance of a low-cost navigated TMS approach in improving coil placement consistency and its effect on motor evoked potentials (MEPs) when targeting the biceps brachii at rest and during voluntary contractions. METHODS We implemented a navigated TMS system using a low-cost 3D camera system and open-source software environment programmed using the Unity 3D engine. MEPs were collected from the biceps brachii at rest and during voluntary contractions across two sessions in ten non-disabled individuals. Motor hotspots were recorded and targeted via two conditions: navigated and conventional. RESULTS The low-cost navigated TMS system reduced coil orientation error (pitch: 1.18°±1.2°, yaw: 1.99°±1.9°, roll: 1.18°±2.2° with navigation, versus pitch: 3.7°±5.7°, yaw: 3.11°±3.1°, roll: 3.8°±9.1° with conventional). The improvement in coil orientation had no effect on MEP amplitudes and variability. CONCLUSIONS The low-cost system is a suitable alternative to expensive systems in tracking the motor hotspot between sessions and quantifying the error in coil placement when delivering TMS. Biceps MEP variability reflects physiological variability across a range of voluntary efforts, that can be captured equally well with navigated or conventional approaches of coil locating.
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Affiliation(s)
- Thibault Roumengous
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Alec B Reutter
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Carrie L Peterson
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, USA
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12
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Geffen A, Bland N, Sale MV. Effects of Slow Oscillatory Transcranial Alternating Current Stimulation on Motor Cortical Excitability Assessed by Transcranial Magnetic Stimulation. Front Hum Neurosci 2021; 15:726604. [PMID: 34588969 PMCID: PMC8473706 DOI: 10.3389/fnhum.2021.726604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/24/2021] [Indexed: 11/13/2022] Open
Abstract
Converging evidence suggests that transcranial alternating current stimulation (tACS) may entrain endogenous neural oscillations to match the frequency and phase of the exogenously applied current and this entrainment may outlast the stimulation (although only for a few oscillatory cycles following the cessation of stimulation). However, observing entrainment in the electroencephalograph (EEG) during stimulation is extremely difficult due to the presence of complex tACS artifacts. The present study assessed entrainment to slow oscillatory (SO) tACS by measuring motor cortical excitability across different oscillatory phases during (i.e., online) and outlasting (i.e., offline) stimulation. 30 healthy participants received 60 trials of intermittent SO tACS (0.75 Hz; 16 s on/off interleaved) at an intensity of 2 mA peak-to-peak. Motor cortical excitability was assessed using transcranial magnetic stimulation (TMS) of the hand region of the primary motor cortex (M1HAND) to induce motor evoked potentials (MEPs) in the contralateral thumb. MEPs were acquired at four time-points within each trial – early online, late online, early offline, and late offline – as well as at the start and end of the overall stimulation period (to probe longer-lasting aftereffects of tACS). A significant increase in MEP amplitude was observed from pre- to post-tACS (paired-sample t-test; t29 = 2.64, P = 0.013, d = 0.48) and from the first to the last tACS block (t29 = −2.93, P = 0.02, d = 0.54). However, no phase-dependent modulation of excitability was observed. Therefore, although SO tACS had a facilitatory effect on motor cortical excitability that outlasted stimulation, there was no evidence supporting entrainment of endogenous oscillations as the underlying mechanism.
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Affiliation(s)
- Asher Geffen
- School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Nicholas Bland
- School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, QLD, Australia.,Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.,School of Human Movement and Nutrition Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Martin V Sale
- School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, QLD, Australia.,Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
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13
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The Effect of Sound and Stimulus Expectation on Transcranial Magnetic Stimulation-Elicited Motor Evoked Potentials. Brain Topogr 2021; 34:720-730. [PMID: 34490506 PMCID: PMC8556164 DOI: 10.1007/s10548-021-00867-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2021] [Indexed: 11/23/2022]
Abstract
The amplitude of motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the motor cortex is influenced by multiple factors. TMS delivery is accompanied by an abrupt clicking noise which can induce a startle response. This study investigated how masking/attenuating the sound produced by the TMS system discharging influences MEP amplitudes. In addition, the effects of increasing the time between consecutive stimuli and of making participants aware of the time at which they would be stimulated were studied. MEPs were recorded from the Flexor Carpi Radialis (FCR) muscle at rest by stimulation at motor threshold (MT), 120% MT and 140% MT intensity. Participants (N = 23) received stimulation under normal (NORMAL) conditions and while: wearing sound-attenuating earmuffs (EAR); listening to white noise (NOISE); the interval between stimuli were prolonged (LONG); stimulation timing was presented on a screen (READY). The results showed that masking (p = 0.020) and attenuating (p = 0.004) the incoming sound significantly reduced the amplitude of MEPs recorded across the intensities of stimulation. Increasing the interval between pulses had no effect on the recorded traces if a jitter was introduced (p = 1), but making participants aware of stimulation timing decreased MEP amplitudes (p = 0.049). These findings suggest that the sound produced by TMS at discharging increases MEP amplitudes and that MEP amplitudes are influenced by stimulus expectation. These confounding factors need to be considered when using TMS to assess corticospinal excitability.
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14
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Kearney-Ramos T, Haney M. Repetitive transcranial magnetic stimulation as a potential treatment approach for cannabis use disorder. Prog Neuropsychopharmacol Biol Psychiatry 2021; 109:110290. [PMID: 33677045 PMCID: PMC9165758 DOI: 10.1016/j.pnpbp.2021.110290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/22/2021] [Accepted: 02/19/2021] [Indexed: 01/22/2023]
Abstract
The expanding legalization of cannabis across the United States is associated with increases in cannabis use, and accordingly, an increase in the number and severity of individuals with cannabis use disorder (CUD). The lack of FDA-approved pharmacotherapies and modest efficacy of psychotherapeutic interventions means that many of those who seek treatment for CUD relapse within the first few months. Consequently, there is a pressing need for innovative, evidence-based treatment development for CUD. Preliminary evidence suggests that repetitive transcranial magnetic stimulation (rTMS) may be a novel, non-invasive therapeutic neuromodulation tool for the treatment of a variety of substance use disorders (SUDs), including recently receiving FDA clearance (August 2020) for use as a smoking cessation aid in tobacco cigarette smokers. However, the potential of rTMS for CUD has not yet been reviewed. This paper provides a primer on therapeutic neuromodulation techniques for SUDs, with a particular focus on reviewing the current status of rTMS research in people who use cannabis. Lastly, future directions are proposed for rTMS treatment development in CUD, with suggestions for study design parameters and clinical endpoints based on current gold-standard practices for therapeutic neuromodulation research.
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Affiliation(s)
- Tonisha Kearney-Ramos
- New York State Psychiatric Institute, New York, NY, USA; Columbia University Irving Medical Center, New York, NY, USA.
| | - Margaret Haney
- New York State Psychiatric Institute, New York, New York, USA,Columbia University Irving Medical Center, New York, New York, USA
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15
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Guder S, Frey BM, Backhaus W, Braass H, Timmermann JE, Gerloff C, Schulz R. The Influence of Cortico-Cerebellar Structural Connectivity on Cortical Excitability in Chronic Stroke. Cereb Cortex 2021; 30:1330-1344. [PMID: 31647536 DOI: 10.1093/cercor/bhz169] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/17/2019] [Accepted: 06/22/2019] [Indexed: 12/11/2022] Open
Abstract
Brain imaging has recently evidenced that the structural state of distinct reciprocal cortico-cerebellar fiber tracts, the dentato-thalamo-cortical tract (DTCT), and the cortico-ponto-cerebellar tract (CPCeT), significantly influences residual motor output in chronic stroke patients, independent from the level of damage to the corticospinal tract (CST). Whether such structural information might also directly relate to measures of cortical excitability is an open question. Eighteen chronic stroke patients with supratentorial ischemic lesions and 17 healthy controls underwent transcranial magnetic stimulation to assess recruitment curves of motor evoked potentials of both hemispheres. Diffusion-weighted imaging and probabilistic tractography were applied to reconstruct reciprocal cortico-cerebellar motor tracts between the primary motor cortex and the cerebellum. Tract-related microstructure was estimated by means of fractional anisotropy, and linear regression modeling was used to relate it to cortical excitability. The main finding was a significant association between cortical excitability and the structural integrity of the DTCT, the main cerebellar outflow tract, independent from the level of damage to the CST. A comparable relationship was neither detectable for the CPCeT nor for the healthy controls. This finding contributes to a mechanistic understanding of the putative supportive role of the cerebellum for residual motor output by facilitating cortical excitability after stroke.
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Affiliation(s)
- Stephanie Guder
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Benedikt M Frey
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Winifried Backhaus
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Hanna Braass
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Jan E Timmermann
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Christian Gerloff
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Robert Schulz
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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16
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Varone G, Hussain Z, Sheikh Z, Howard A, Boulila W, Mahmud M, Howard N, Morabito FC, Hussain A. Real-Time Artifacts Reduction during TMS-EEG Co-Registration: A Comprehensive Review on Technologies and Procedures. SENSORS 2021; 21:s21020637. [PMID: 33477526 PMCID: PMC7831109 DOI: 10.3390/s21020637] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 01/24/2023]
Abstract
Transcranial magnetic stimulation (TMS) excites neurons in the cortex, and neural activity can be simultaneously recorded using electroencephalography (EEG). However, TMS-evoked EEG potentials (TEPs) do not only reflect transcranial neural stimulation as they can be contaminated by artifacts. Over the last two decades, significant developments in EEG amplifiers, TMS-compatible technology, customized hardware and open source software have enabled researchers to develop approaches which can substantially reduce TMS-induced artifacts. In TMS-EEG experiments, various physiological and external occurrences have been identified and attempts have been made to minimize or remove them using online techniques. Despite these advances, technological issues and methodological constraints prevent straightforward recordings of early TEPs components. To the best of our knowledge, there is no review on both TMS-EEG artifacts and EEG technologies in the literature to-date. Our survey aims to provide an overview of research studies in this field over the last 40 years. We review TMS-EEG artifacts, their sources and their waveforms and present the state-of-the-art in EEG technologies and front-end characteristics. We also propose a synchronization toolbox for TMS-EEG laboratories. We then review subject preparation frameworks and online artifacts reduction maneuvers for improving data acquisition and conclude by outlining open challenges and future research directions in the field.
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Affiliation(s)
- Giuseppe Varone
- Department of Medical and Surgical Sciences, Magna Greacia University of Catanzaro, 88100 Catanzaro, Italy;
| | - Zain Hussain
- College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH16 4TJ, UK; (Z.H.); (Z.S.)
- Howard Brain Sciences Foundation, Providence, RI 02906, USA;
| | - Zakariya Sheikh
- College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH16 4TJ, UK; (Z.H.); (Z.S.)
| | - Adam Howard
- Howard Brain Sciences Foundation, Providence, RI 02906, USA;
| | - Wadii Boulila
- RIADI Laboratory, National School of Computer Sciences, University of Manouba, Manouba 2010, Tunisia;
- IS Department, College of Computer Science and Engineering, Taibah University, Medina 42353, Saudi Arabia
| | - Mufti Mahmud
- Department of Computer Science and Medical Technology Innovation Facility, Nottingham Trent University, Clifton, Nottingham NG11 8NS, UK;
| | - Newton Howard
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX3 9DU, UK;
| | | | - Amir Hussain
- School of Computing, Edinburgh Napier University, Edinburgh EH11 4BN, UK;
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17
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Ammann C, Guida P, Caballero-Insaurriaga J, Pineda-Pardo JA, Oliviero A, Foffani G. A framework to assess the impact of number of trials on the amplitude of motor evoked potentials. Sci Rep 2020; 10:21422. [PMID: 33293541 PMCID: PMC7722939 DOI: 10.1038/s41598-020-77383-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022] Open
Abstract
The amplitude of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) is a common yet highly variable measure of corticospinal excitability. The tradeoff between maximizing the number of trials and minimizing experimental time remains a hurdle. It is therefore important to establish how many trials should be used. The aim of this study is not to provide rule-of-thumb answers that may be valid only in specific experimental conditions, but to offer a more general framework to inform the decision about how many trials to use under different experimental conditions. Specifically, we present a set of equations that show how the number of trials affects single-subject MEP amplitude, population MEP amplitude, hypothesis testing and test-retest reliability, depending on the variability within and between subjects. The equations are derived analytically, validated with Monte Carlo simulations, and representatively applied to experimental data. Our findings show that the minimum number of trials for estimating single-subject MEP amplitude largely depends on the experimental conditions and on the error considered acceptable by the experimenter. Conversely, estimating population MEP amplitude and hypothesis testing are markedly more dependent on the number of subjects than on the number of trials. These tools and results help to clarify the impact of the number of trials in the design and reproducibility of past and future experiments.
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Affiliation(s)
- Claudia Ammann
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
| | - Pasqualina Guida
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
| | | | - José A Pineda-Pardo
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Guglielmo Foffani
- HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Universidad CEU-San Pablo, Madrid, Spain.
- CIBERNED, Instituto de Salud Carlos III, Madrid, Spain.
- Hospital Nacional de Parapléjicos, Toledo, Spain.
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18
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Giuffre A, Kahl CK, Zewdie E, Wrightson JG, Bourgeois A, Condliffe EG, Kirton A. Reliability of robotic transcranial magnetic stimulation motor mapping. J Neurophysiol 2020; 125:74-85. [PMID: 33146067 DOI: 10.1152/jn.00527.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Robotic transcranial magnetic stimulation (TMS) is a noninvasive and safe tool that produces cortical motor maps using neuronavigational and neuroanatomical images. Motor maps are individualized representations of the primary motor cortex (M1) topography that may reflect developmental and interventional plasticity. Results of TMS motor map reliability testing have been variable, and robotic measures are undefined. We aimed to determine the short- and long-term reliability of robotic TMS motor maps. Twenty healthy participants underwent motor mapping at baseline, 24 h, and 4 wk. A 12 × 12 grid (7-mm spacing) was placed over the left M1, centered over the hand knob area. Four suprathreshold stimulations were delivered at each grid point. First dorsal interosseous (FDI) motor-evoked potentials (MEPs) were analyzed offline to generate map characteristics of area, volume, center of gravity (COG), and hotspot magnitude. Subsets of each outcome corresponding to 75%, 50%, and 25% of each map were determined. Reliability measures including intraclass correlation coefficient (ICC), minimal detectable change (MDC), and standard error of measure (SEM) were calculated. Map volume, COG, and hotspot magnitude were the most reliable measures (good-to-excellent) over both short- and long-term sessions. Map area reliability was poor-to-moderate for short- and long-term sessions. Smaller map percentile subsets showed decreased variability but only minimal improvements in reliability. MDC for most outcomes was >50%. Procedures were well tolerated with no serious adverse events. Robotic TMS motor mapping is relatively reliable over time, but careful consideration of specific outcomes is required for this method to interrogate plasticity in the human motor system.NEW & NOTEWORTHY Robotic transcranial magnetic stimulation (TMS) is a noninvasive and safe tool that produces cortical motor maps-individualized representations of the primary motor cortex (M1) topography-that may reflect developmental and interventional plasticity. This study is the first to evaluate short- and long-term relative and absolute reliability of TMS mapping outcomes at various M1 excitability levels using novel robotic neuronavigated TMS.
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Affiliation(s)
- Adrianna Giuffre
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, Alberta, Canada.,Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cynthia K Kahl
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Psychiatry, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ephrem Zewdie
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, Alberta, Canada.,Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - James G Wrightson
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anna Bourgeois
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Elizabeth G Condliffe
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Adam Kirton
- Calgary Pediatric Stroke Program, Alberta Children's Hospital, Calgary, Alberta, Canada.,Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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19
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Welch JF, Argento PJ, Mitchell GS, Fox EJ. Reliability of diaphragmatic motor-evoked potentials induced by transcranial magnetic stimulation. J Appl Physiol (1985) 2020; 129:1393-1404. [PMID: 33031020 DOI: 10.1152/japplphysiol.00486.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The diaphragmatic motor-evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) permits electrophysiological assessment of the cortico-diaphragmatic pathway. Despite the value of TMS for investigating diaphragm motor integrity in health and disease, reliability of the technique has not been established. The study aim was to determine within- and between-session reproducibility of surface electromyogram recordings of TMS-evoked diaphragm potentials. Fifteen healthy young adults participated (6 females, age = 29 ± 7 yr). Diaphragm activation was determined by gradually increasing the stimulus intensity from 60 to 100% of maximal stimulator output (MSO). A minimum of seven stimulations were performed at each intensity. A second block of stimuli was delivered 30 min later for within-day comparisons, and a third block was performed on a separate day for between-day comparisons. Reliability of diaphragm MEPs was assessed at 100% MSO using intraclass correlation coefficients (ICC) and 95% limits of agreement (LOA). MEP latency (ICC = 0.984, P < 0.001), duration (ICC = 0.958, P < 0.001), amplitude (ICC = 0.950, P < 0.001), and area (ICC = 0.956, P < 0.001) were highly reproducible within-day. Between-day reproducibility was good to excellent for all MEP characteristics (latency ICC = 0.953, P < 0.001; duration ICC = 0.879, P = 0.002; amplitude ICC = 0.789, P = 0.019; area ICC = 0.815, P = 0.012). Data revealed less precision between-day versus within-day, as evidenced by wider LOA for all MEP characteristics. Large within- and between-subject variability in MEP amplitude and area was observed. In conclusion, TMS is a reliable means of inducing diaphragm potentials in most healthy individuals.NEW & NOTEWORTHY Transcranial magnetic stimulation (TMS) is a noninvasive technique to assess neural impulse conduction along the cortico-diaphragmatic pathway. The reliability of diaphragm motor-evoked potentials (MEP) induced by TMS is unknown. Notwithstanding large variability in MEP amplitude, we found good-to-excellent reproducibility of all MEP characteristics (latency, duration, amplitude, and area) both within- and between-day in healthy adult men and women. Our findings support the use of TMS and surface EMG to assess diaphragm activation in humans.
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Affiliation(s)
- Joseph F Welch
- Breathing Research and Therapeutics Center, Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Patrick J Argento
- Herbert Wertheim College of Engineering, University of Florida, Gainesville, Florida
| | - Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Emily J Fox
- Breathing Research and Therapeutics Center, Department of Physical Therapy, University of Florida, Gainesville, Florida.,Brooks Rehabilitation, Jacksonville, Florida
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20
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Corp DT, Bereznicki HGK, Clark GM, Youssef GJ, Fried PJ, Jannati A, Davies CB, Gomes-Osman J, Stamm J, Chung SW, Bowe SJ, Rogasch NC, Fitzgerald PB, Koch G, Di Lazzaro V, Pascual-Leone A, Enticott PG. Large-scale analysis of interindividual variability in theta-burst stimulation data: Results from the 'Big TMS Data Collaboration'. Brain Stimul 2020; 13:1476-1488. [PMID: 32758665 PMCID: PMC7494610 DOI: 10.1016/j.brs.2020.07.018] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Many studies have attempted to identify the sources of interindividual variability in response to theta-burst stimulation (TBS). However, these studies have been limited by small sample sizes, leading to conflicting results. OBJECTIVE/HYPOTHESIS This study brought together over 60 TMS researchers to form the 'Big TMS Data Collaboration', and create the largest known sample of individual participant TBS data to date. The goal was to enable a more comprehensive evaluation of factors driving TBS response variability. METHODS 118 corresponding authors of TMS studies were emailed and asked to provide deidentified individual TMS data. Mixed-effects regression investigated a range of individual and study level variables for their contribution to iTBS and cTBS response variability. RESULTS 430 healthy participants' TBS data was pooled across 22 studies (mean age = 41.9; range = 17-82; females = 217). Baseline MEP amplitude, age, target muscle, and time of day significantly predicted iTBS-induced plasticity. Baseline MEP amplitude and timepoint after TBS significantly predicted cTBS-induced plasticity. CONCLUSIONS This is the largest known study of interindividual variability in TBS. Our findings indicate that a significant portion of variability can be attributed to the methods used to measure the modulatory effects of TBS. We provide specific methodological recommendations in order to control and mitigate these sources of variability.
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Affiliation(s)
- Daniel T Corp
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia; Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Hannah G K Bereznicki
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Gillian M Clark
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - George J Youssef
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia; Centre for Adolescent Health, Murdoch Children's Research Institute, Parkville, Australia
| | - Peter J Fried
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ali Jannati
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charlotte B Davies
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Joyce Gomes-Osman
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Physical Therapy, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Julie Stamm
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Sung Wook Chung
- Monash Alfred Psychiatry Research Centre, Central Clinical School, The Alfred and Monash University, Melbourne, Australia
| | - Steven J Bowe
- Deakin Biostatistics Unit Faculty of Health Deakin University, Geelong, Australia
| | - Nigel C Rogasch
- Discipline of Psychiatry, Adelaide Medical School, University of Adelaide, Adelaide, Australia; Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, Australia; The Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, Central Clinical School, The Alfred and Monash University, Melbourne, Australia; Epworth Centre for Innovation in Mental Health, Epworth HealthCare and Central Clinical School, Melbourne, Australia
| | - Giacomo Koch
- Non-invasive Brain Stimulation Unit, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Biomedical and Specialty Surgical Sciences, Section of Human Physiology, University of Ferrara, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology and Neurobiology, Università Campus Bio-Medico, Rome, Italy
| | - Alvaro Pascual-Leone
- Hinda and Arthur Marcus Institute for Aging Research. Hebrew SeniorLife, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Guttmann Brain Health Institute, Institut Guttmann de Neurorehabilitació, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
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21
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Bekkali S, Youssef GJ, Donaldson PH, He J, Do M, Hyde C, Barhoun P, Enticott PG. Do Gaze Behaviours during Action Observation Predict Interpersonal Motor Resonance? Soc Cogn Affect Neurosci 2020; 17:61-71. [PMID: 32780868 PMCID: PMC8824634 DOI: 10.1093/scan/nsaa106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 06/16/2020] [Accepted: 07/21/2020] [Indexed: 12/01/2022] Open
Abstract
Interpersonal motor resonance (IMR) is a common putative index of the mirror neuron system (MNS), a network containing specialised cells that fire during both action execution and observation. Visual content inputs to the MNS, however, it is unclear whether visual behaviours mediate the putative MNS response. We aimed to examine gaze effects on IMR during action observation. Neurotypical adults (N = 99; 60 female) underwent transcranial magnetic stimulation, electromyography, and eye-tracking during the observation of videos of actors performing grasping actions. IMR was measured as a percentage change in motor evoked potentials (MEPs) of the first dorsal interosseous muscle during action observation relative to baseline. MEP facilitation was observed during action observation, indicating IMR (65.43%, SE = 11.26%, P < 0.001). Fixations occurring in biologically relevant areas (face/hand/arm) yielded significantly stronger IMR (81.03%, SE = 14.15%) than non-biological areas (63.92%, SE = 14.60, P = 0.012). This effect, however, was only evident in the first of four experimental blocks. Our results suggest that gaze fixation can modulate IMR, but this may be affected by the salience and novelty of the observed action. These findings have important methodological implications for future studies in both clinical and healthy populations.
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Affiliation(s)
- Soukayna Bekkali
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
| | - George J Youssef
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia.,Centre for Adolescent Health, Murdoch Children's Research Institute, 50 Flemington Rd, Parkville, Melbourne, Victoria, 3052, Australia
| | - Peter H Donaldson
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
| | - Jason He
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia.,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Forensic and Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, United Kingdom
| | - Michael Do
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
| | - Christian Hyde
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
| | - Pamela Barhoun
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, 221 Burwood Hwy, Burwood, Victoria, 3125, Australia
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22
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Hassanzahraee M, Zoghi M, Jaberzadeh S. Longer Transcranial Magnetic Stimulation Intertrial Interval Increases Size, Reduces Variability, and Improves the Reliability of Motor Evoked Potentials. Brain Connect 2020; 9:770-776. [PMID: 31744309 DOI: 10.1089/brain.2019.0714] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
High rates of variability in the amplitude of transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs), a popular method for assessing corticospinal excitability (CSE), make it essential to examine inherent reliability of the MEP amplitude. We aimed to investigate the effects of different intertrial intervals (ITIs) of single-pulse TMS on the amplitude, variability, and test-retest reliability of MEPs. Twenty-five TMS single pulses were recorded at four different ITIs of 5, 10, 15, and 20 sec from 15 healthy participants who attended two experimental sessions. Repeated measures analysis of variance (rmANOVA) and standardized z-value standard deviations (SDs) were used to investigate the effects of ITIs on MEP amplitudes and variability. Test-retest reliability of MEP amplitudes was also assessed using rmANOVA and intraclass correlation (ICC). rmANOVA revealed significantly larger MEP amplitudes following ITIs of 10, 15, and 20 sec compared with ITI 5, with no significant increases between ITIs of 15 and 20 sec. Standardized z-value SDs revealed variability rate reduction following longer ITIs with significant reductions occurring following ITIs of 10, 15, and 20 sec compared with ITI 5 with no significant difference between ITIs of 15 and 20 sec. rmANOVA showed no significant Time main effect on the MEP changes confirming within- and between-session agreement. ICCs reported significant within- and between-session reliability in all selected ITIs. The findings of the current study indicate that longer ITIs up to 15 sec can significantly induce larger MEPs with lower variability and higher reliability. The increase in ITIs not only reduces the chance of TMS-induced changes in CSE but also helps us to use this assessment tool in studies with smaller sample sizes.
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Affiliation(s)
- Maryam Hassanzahraee
- Noninvasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Melbourne, Australia
| | - Shapour Jaberzadeh
- Noninvasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
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23
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Fleischmann R, Köhn A, Tränkner S, Brandt SA, Schmidt S. Individualized Template MRI Is a Valid and Reliable Alternative to Individual MRI for Spatial Tracking in Navigated TMS Studies in Healthy Subjects. Front Hum Neurosci 2020; 14:174. [PMID: 32477086 PMCID: PMC7241258 DOI: 10.3389/fnhum.2020.00174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/20/2020] [Indexed: 11/28/2022] Open
Abstract
Objectives: Navigated transcranial magnetic stimulation (nTMS) provides significant benefits over classic TMS. Yet, the acquisition of individual structural magnetic resonance images (MRIindividual) is a time-consuming, expensive, and not feasible prerequisite in all subjects for spatial tracking and anatomical guidance in nTMS studies. We hypothesize that spatial transformation can be used to adjust MRI templates to individual head shapes (MRIwarped) and that TMS parameters do not differ between nTMS using MRIindividual or MRIwarped. Materials and Methods: Twenty identical TMS sessions, each including four different navigation conditions, were conducted in 10 healthy subjects (one female, 27.4 ± 3.8 years), i.e., twice per subject by two researchers to additionally assess interrater reliabilities. MRIindividual were acquired for all subjects. MRIwarped were obtained through the spatial transformation of a template MRI following a 5-, 9-and 36-point head surface registration (MRIwarped_5, MRIwarped_9, MRIwarped_36). Stimulation hotspot locations, resting motor threshold (RMT), 500 μV motor threshold (500 μV-MT), and mean absolute motor evoked potential difference (MAD) of primary motor cortex (M1) examinations were compared between nTMS using either MRIwarped variants or MRIindividual and non-navigated TMS. Results: M1 hotspots were spatially consistent between MRIindividual and MRIwarped_36 (insignificant deviation by 4.79 ± 2.62 mm). MEP thresholds and variance were also equivalent between MRIindividual and MRIwarped_36 with mean differences of RMT by −0.05 ± 2.28% maximum stimulator output (%MSO; t(19) = −0.09, p = 0.923), 500 μV-MT by −0.15 ± 1.63%MSO (t(19) = −0.41, p = 0.686) and MAD by 70.5 ± 214.38 μV (t(19) = 1.47, p = 0.158). Intraclass correlations (ICC) of motor thresholds were between 0.88 and 0.97. Conclusions: NTMS examinations of M1 yield equivalent topographical and functional results using MRIindividual and MRIwarped if a sufficient number of registration points are used.
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Affiliation(s)
- Robert Fleischmann
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Neurology, University Medicine Greifswald, Greifswald, Germany
| | - Arvid Köhn
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Steffi Tränkner
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A Brandt
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sein Schmidt
- Vision and Motor System Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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24
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Lorenz S, Alex B, Kammer T. Ten minutes of transcranial static magnetic field stimulation does not reliably modulate motor cortex excitability. PLoS One 2020; 15:e0233614. [PMID: 32453767 PMCID: PMC7250443 DOI: 10.1371/journal.pone.0233614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/08/2020] [Indexed: 12/18/2022] Open
Abstract
Recently, modulatory effects of static magnetic field stimulation (tSMS) on excitability of the motor cortex have been reported. In our previous study we failed to replicate these results. It was suggested that the lack of modulatory effects was due to the use of an auditory oddball task in our study. Thus, we aimed to evaluate the role of an oddball task on the effects of tSMS on motor cortex excitability. In a within-subject-design we compared 10 minutes tSMS with and without oddball task. In one of the two sessions subjects had to solve an auditory oddball task during the exposure to the magnet, whereas there was no task during exposure in the other session. Motor cortex excitability was measured before and after tSMS. No modulation was observed in any condition. However, when data were pooled regarding the order of the sessions, a trend for an increase of excitability was observed in the first session compared to the second session. We now can rule out that the auditory oddball task destroys tSMS effects, as postulated. Our results rather suggest that fluctuations in the amplitudes of single pulse motor evoked potentials may possibly mask weak modulatory effects but may also lead to false positive results if the number of subjects in a study is too low. In addition, there might be a habituation effect to the whole procedure, resulting in less variability when subjects underwent the same experiment twice.
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Affiliation(s)
- Sabrina Lorenz
- Department of Psychiatry, Section for Neurostimulation, University of Ulm, Ulm, Germany
- * E-mail:
| | - Birte Alex
- Department of Psychiatry, Section for Neurostimulation, University of Ulm, Ulm, Germany
| | - Thomas Kammer
- Department of Psychiatry, Section for Neurostimulation, University of Ulm, Ulm, Germany
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25
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Mirbagheri A, Schneider H, Zdunczyk A, Vajkoczy P, Picht T. NTMS mapping of non-primary motor areas in brain tumour patients and healthy volunteers. Acta Neurochir (Wien) 2020; 162:407-416. [PMID: 31768755 DOI: 10.1007/s00701-019-04086-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/20/2019] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Navigated transcranial magnetic stimulation (nTMS) has been increasingly used for presurgical cortical mapping of the primary motor cortex (M1) but remains controversial for the evaluation of non-primary motor areas (NPMA). This study investigates clinical and neurophysiological parameters in brain tumour patients and healthy volunteers to decide whether single-pulse biphasic nTMS allows to reliably elicite MEP outside from M1 or not. MATERIALS AND METHODS Twelve brain tumour patients and six healthy volunteers underwent M1 nTMS mapping. NPMA nTMS mapping followed using 120% and 150% M1 resting motor threshold (RMT) stimulation intensity. Spearman's correlation analysis tested the association of clinical and neurophysiological parameters between M1 and NPMA mapping. RESULTS A total of 88.81% of nTMS stimulations in NPMA in patients/83.87% in healthy volunteers in patients/83.87% in healthy volunteers did not result in MEPs ≥ 50 μV. Positive nTMS mapping in NPMA correlated with higher stimulation intensity and larger M1 areas in patients (120% M1 RMT SI p = 0.005/150% M1 RMT SI p = 0.198). CONCLUSION Our findings indicate that in case of positive nTMS mapping in NPMA, MEPs originate mostly from M1. For future studies, MEP parameters and TMS coil rotation should be studied closely to assess the risk for postoperative motor deterioration.
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Affiliation(s)
- Andia Mirbagheri
- Department of Neurosurgery, Charité University Medicine, Charitéplatz 1, Berlin, Germany.
| | - Heike Schneider
- Department of Neurosurgery, Charité University Medicine, Charitéplatz 1, Berlin, Germany
| | - Anna Zdunczyk
- Department of Neurosurgery, Charité University Medicine, Charitéplatz 1, Berlin, Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité University Medicine, Charitéplatz 1, Berlin, Germany
| | - Thomas Picht
- Department of Neurosurgery, Charité University Medicine, Charitéplatz 1, Berlin, Germany
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26
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Lafleur LP, Klees-Themens G, Chouinard-Leclaire C, Larochelle-Brunet F, Tremblay S, Lepage JF, Théoret H. Neurophysiological aftereffects of 10 Hz and 20 Hz transcranial alternating current stimulation over bilateral sensorimotor cortex. Brain Res 2020; 1727:146542. [PMID: 31712086 DOI: 10.1016/j.brainres.2019.146542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/28/2022]
Abstract
Alpha (8-12 Hz) and beta (13-30 Hz) oscillations are believed to be involved in motor control. Their modulation with transcranial alternating current stimulation (tACS) has been shown to alter motor behavior and cortical excitability. The aim of the present study was to determine whether tACS applied bilaterally over sensorimotor cortex at 10 Hz and 20 Hz modulates interhemispheric interactions and corticospinal excitability. Thirty healthy volunteers participated in a randomized, cross-over, sham-controlled, double-blind protocol. Sham and active tACS (10 Hz, 20 Hz, 1 mA) were applied for 20 min over bilateral sensorimotor areas. The physiological effects of tACS on corticospinal excitability and interhemispheric inhibition were assessed with transcranial magnetic stimulation. Physiological mirror movements were assessed to measure the overflow of motor activity to the contralateral M1 during voluntary muscle contraction. Bilateral 10 Hz tACS reduced corticospinal excitability. There was no significant effect of tACS on physiological mirror movements and interhemispheric inhibition. Ten Hz tACS was associated with response patterns consistent with corticospinal inhibition in 57% of participants. The present results indicate that application of tACS at the alpha frequency can induce aftereffects in sensorimotor cortex of healthy individuals.
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Affiliation(s)
- Louis-Philippe Lafleur
- Department of psychologie, Université de Montréal, Montréal, Canada; Centre de recherche du Centre Hospitalier Universitaire Sainte-Justine, Montréal, Canada
| | | | | | | | - Sara Tremblay
- Department of Psychology, Carleton University, Ottawa, Canada
| | - Jean-Francois Lepage
- Département de Pédiatrie, Médecine nucléaire et radiobiologie, Centre de recherche du CHU Sherbrooke, Sherbrooke, Canada
| | - Hugo Théoret
- Department of psychologie, Université de Montréal, Montréal, Canada; Centre de recherche du Centre Hospitalier Universitaire Sainte-Justine, Montréal, Canada.
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27
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Burgess JD, Major BP, McNeel C, Clark GM, Lum JAG, Enticott PG. Learning to Expect: Predicting Sounds During Movement Is Related to Sensorimotor Association During Listening. Front Hum Neurosci 2019; 13:215. [PMID: 31333431 PMCID: PMC6624421 DOI: 10.3389/fnhum.2019.00215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 06/11/2019] [Indexed: 11/13/2022] Open
Abstract
Sensory experiences, such as sound, often result from our motor actions. Over time, repeated sound-producing performance can generate sensorimotor associations. However, it is not clear how sensory and motor information are associated. Here, we explore if sensory prediction is associated with the formation of sensorimotor associations during a learning task. We recorded event-related potentials (ERPs) while participants produced index and little finger-swipes on a bespoke device, generating novel sounds. ERPs were also obtained as participants heard those sounds played back. Peak suppression was compared to assess sensory prediction. Additionally, transcranial magnetic stimulation (TMS) was used during listening to generate finger-motor evoked potentials (MEPs). MEPs were recorded before and after training upon hearing these sounds, and then compared to reveal sensorimotor associations. Finally, we explored the relationship between these components. Results demonstrated that an increased positive-going peak (e.g., P2) and a suppressed negative-going peak (e.g., N2) were recorded during action, revealing some sensory prediction outcomes (P2: p = 0.050, ηp2 = 0.208; N2: p = 0.001, ηp2 = 0.474). Increased MEPs were also observed upon hearing congruent sounds compared with incongruent sounds (i.e., associated to a finger), demonstrating precise sensorimotor associations that were not present before learning (Index finger: p < 0.001, ηp2 = 0.614; Little finger: p < 0.001, ηp2 = 0.529). Consistent with our broad hypotheses, a negative association between the MEPs in one finger during listening and ERPs during performance of the other was observed (Index finger MEPs and Fz N1 action ERPs; r = −0.655, p = 0.003). Overall, data suggest that predictive mechanisms are associated with the fine-tuning of sensorimotor associations.
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Affiliation(s)
- Jed D Burgess
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Brendan P Major
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Claire McNeel
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Gillian M Clark
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Jarrad A G Lum
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, VIC, Australia
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28
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Jooss A, Haberbosch L, Köhn A, Rönnefarth M, Bathe-Peters R, Kozarzewski L, Fleischmann R, Scholz M, Schmidt S, Brandt SA. Motor Task-Dependent Dissociated Effects of Transcranial Random Noise Stimulation in a Finger-Tapping Task Versus a Go/No-Go Task on Corticospinal Excitability and Task Performance. Front Neurosci 2019; 13:161. [PMID: 30872997 PMCID: PMC6400855 DOI: 10.3389/fnins.2019.00161] [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: 10/30/2018] [Accepted: 02/12/2019] [Indexed: 01/18/2023] Open
Abstract
Background and Objective: Transcranial random noise stimulation (tRNS) is an emerging non-invasive brain stimulation technique to modulate brain function, with previous studies highlighting its considerable benefits in therapeutic stimulation of the motor system. However, high variability of results and bidirectional task-dependent effects limit more widespread clinical application. Task dependency largely results from a lack of understanding of the interaction between externally applied tRNS and the endogenous state of neural activity during stimulation. Hence, the aim of this study was to investigate the task dependency of tRNS-induced neuromodulation in the motor system using a finger-tapping task (FT) versus a go/no-go task (GNG). We hypothesized that the tasks would modulate tRNS’ effects on corticospinal excitability (CSE) and task performance in opposite directions. Methods: Thirty healthy subjects received 10 min of tRNS of the dominant primary motor cortex in a double-blind, sham-controlled study design. tRNS was applied during two well-established tasks tied to diverging brain states. Accordingly, participants were randomly assigned to two equally-sized groups: the first group performed a simple motor training task (FT task), known primarily to increase CSE, while the second group performed an inhibitory control task (go/no-go task) associated with inhibition of CSE. To establish task-dependent effects of tRNS, CSE was evaluated prior to- and after stimulation with navigated transcranial magnetic stimulation. Results: In an ‘activating’ motor task, tRNS during FT significantly facilitated CSE. FT task performance improvements, shown by training-related reductions in intertap intervals and increased number of finger taps, were similar for both tRNS and sham stimulation. In an ‘inhibitory’ motor task, tRNS during GNG left CSE unchanged while inhibitory control was enhanced as shown by slowed reaction times and enhanced task accuracy during and after stimulation. Conclusion: We provide evidence that tRNS-induced neuromodulatory effects are task-dependent and that resulting enhancements are specific to the underlying task-dependent brain state. While mechanisms underlying this effect require further investigation, these findings highlight the potential of tRNS in enhancing task-dependent brain states to modulate human behavior.
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Affiliation(s)
- Andreas Jooss
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Linus Haberbosch
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Arvid Köhn
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Maria Rönnefarth
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Rouven Bathe-Peters
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Leonard Kozarzewski
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Robert Fleischmann
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Michael Scholz
- Neural Information Processing Group, Technische Universität Berlin, Berlin, Germany
| | - Sein Schmidt
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A Brandt
- Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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29
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Cole EJ, Barraclough NE. Timing of mirror system activation when inferring the intentions of others. Brain Res 2018; 1700:109-117. [DOI: 10.1016/j.brainres.2018.07.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 10/28/2022]
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30
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Adank P, Kennedy-Higgins D, Maegherman G, Hannah R, Nuttall HE. Effects of Coil Orientation on Motor Evoked Potentials From Orbicularis Oris. Front Neurosci 2018; 12:683. [PMID: 30483044 PMCID: PMC6243052 DOI: 10.3389/fnins.2018.00683] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/11/2018] [Indexed: 11/13/2022] Open
Abstract
This study aimed to characterize effects of coil orientation on the size of Motor Evoked Potentials (MEPs) from both sides of Orbicularis Oris (OO) and both First Dorsal Interosseous (FDI) muscles, following stimulation to left lip and left hand Primary Motor Cortex. Using a 70 mm figure-of-eight coil, we collected MEPs from eight different orientations while recording from contralateral and ipsilateral OO and FDI using a monophasic pulse delivered at 120% active motor threshold. MEPs from OO were evoked consistently for six orientations for contralateral and ipsilateral sites. Contralateral orientations 0°, 45°, 90°, and 315° were found to best elicit OO MEPs with a likely cortical origin. The largest FDI MEPs were recorded for contralateral 45°, invoking a posterior-anterior (PA) current flow. Orientations traditionally used for FDI were also found to be suitable for eliciting OO MEPs. Individuals vary more in their optimal orientation for OO than for FDI. It is recommended that researchers iteratively probe several orientations when eliciting MEPs from OO. Several orientations likely induced direct activation of facial muscles.
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Affiliation(s)
- Patti Adank
- Department of Speech, Hearing and Phonetic Sciences, University College London, London, United Kingdom
| | - Dan Kennedy-Higgins
- Department of Speech, Hearing and Phonetic Sciences, University College London, London, United Kingdom
| | - Gwijde Maegherman
- Department of Speech, Hearing and Phonetic Sciences, University College London, London, United Kingdom
| | - Ricci Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Helen E. Nuttall
- Department of Speech, Hearing and Phonetic Sciences, University College London, London, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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31
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Dissanayaka T, Zoghi M, Farrell M, Egan G, Jaberzadeh S. Comparison of Rossini-Rothwell and adaptive threshold-hunting methods on the stability of TMS induced motor evoked potentials amplitudes. J Neurosci Res 2018; 96:1758-1765. [DOI: 10.1002/jnr.24319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 07/31/2018] [Accepted: 07/31/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Thusharika Dissanayaka
- Faculty of Medicine, Nursing and Health Sciences, Department of Physiotherapy, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied health; La Trobe University; Melbourne Victoria Australia
| | - Michael Farrell
- Monash Biomedical Imaging; Monash University; Melbourne Victoria Australia
- Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences; Monash University; Clayton Victoria Australia
| | - Gary Egan
- Monash Biomedical Imaging; Monash University; Melbourne Victoria Australia
| | - Shapour Jaberzadeh
- Faculty of Medicine, Nursing and Health Sciences, Department of Physiotherapy, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
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32
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Action observation effects reflect the modular organization of the human motor system. Cortex 2017; 95:104-118. [PMID: 28866300 DOI: 10.1016/j.cortex.2017.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/27/2017] [Accepted: 07/20/2017] [Indexed: 11/21/2022]
Abstract
Action observation, similarly to action execution, facilitates the observer's motor system and Transcranial Magnetic Stimulation (TMS) has been instrumental in exploring the nature of these motor activities. However, contradictory findings question some of the fundamental assumptions regarding the neural computations run by the Action Observation Network (AON). To better understand this issue, we delivered TMS over the observers' motor cortex at two timings of two reaching-grasping actions (precision vs power grip) and we recorded Motor-Evoked Potentials (4 hand/arm muscles; MEPs). At the same time, we also recorded whole-hand TMS Evoked Kinematics (8 hand elevation angles; MEKs) that capture the global functional motor output, as opposed to the limited view offered by recording few muscles. By repeating the same protocol twice, and a third time after continuous theta burst stimulation (cTBS) over the motor cortex, we observe significant time-dependent grip-specific MEPs and MEKs modulations, that disappeared after cTBS. MEKs, differently from MEPs, exhibit a consistent significant modulation across pre-cTBS sessions. Beside clear methodological implications, the multidimensionality of MEKs opens a window on muscle synergies needed to overcome system redundancy. By providing better access to the AON computations, our results strengthen the idea that action observation shares key organizational similarities with action execution.
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33
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Physical activity levels determine exercise-induced changes in brain excitability. PLoS One 2017; 12:e0173672. [PMID: 28278300 PMCID: PMC5344515 DOI: 10.1371/journal.pone.0173672] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/25/2017] [Indexed: 12/22/2022] Open
Abstract
Emerging evidence suggests that regular physical activity can impact cortical function and facilitate plasticity. In the present study, we examined how physical activity levels influence corticospinal excitability and intracortical circuitry in motor cortex following a single session of moderate intensity aerobic exercise. We aimed to determine whether exercise-induced short-term plasticity differed between high versus low physically active individuals. Participants included twenty-eight young, healthy adults divided into two equal groups based on physical activity level determined by the International Physical Activity Questionnaire: low-to-moderate (LOW) and high (HIGH) physical activity. Transcranial magnetic stimulation was used to assess motor cortex excitability via motor evoked potential (MEP) recruitment curves for the first dorsal interosseous (FDI) muscle at rest (MEPREST) and during tonic contraction (MEPACTIVE), short-interval intracortical inhibition (SICI) and facilitation (SICF), and intracortical facilitation (ICF). All dependent measures were obtained in the resting FDI muscle, with the exception of AMT and MEPACTIVE recruitment curves that were obtained during tonic FDI contraction. Dependent measures were acquired before and following moderate intensity aerobic exercise (20 mins, ~60% of the age-predicted maximal heart rate) performed on a recumbent cycle ergometer. Results indicate that MEPREST recruitment curve amplitudes and area under the recruitment curve (AURC) were increased following exercise in the HIGH group only (p = 0.002 and p = 0.044, respectively). SICI and ICF were reduced following exercise irrespective of physical activity level (p = 0.007 and p = 0.04, respectively). MEPACTIVE recruitment curves and SICF were unaltered by exercise. These findings indicate that the propensity for exercise-induced plasticity is different in high versus low physically active individuals. Additionally, these data highlight that a single session of aerobic exercise can transiently reduce inhibition in the motor cortex regardless of physical activity level, potentially priming the system for plasticity induction.
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Hashemirad F, Zoghi M, Fitzgerald PB, Jaberzadeh S. Reliability of Motor Evoked Potentials Induced by Transcranial Magnetic Stimulation: The Effects of Initial Motor Evoked Potentials Removal. Basic Clin Neurosci 2017; 8:43-50. [PMID: 28446949 PMCID: PMC5396172 DOI: 10.15412/j.bcn.03080106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Transcranial magnetic stimulation (TMS) is a useful tool for assessment of corticospinal excitability (CSE) changes in both healthy individuals and patients with brain disorders. The usefulness of TMS-elicited motor evoked potentials (MEPs) for the assessment of CSE in a clinical context depends on their intra-and inter-session reliability. This study aimed to evaluate if removal of initial MEPs elicited by using two types of TMS techniques influences the reliability scores and whether this effect is different in blocks with variable number of MEPs. METHODS Twenty-three healthy participants were recruited in this study. The stimulus intensity was set at 120% of resting motor threshold (RMT) for one group while the stimulus intensity was adjusted to record MEPs up to 1 mV for the other group. Twenty MEPs were recorded at 3 time points on 2 separate days. An intra-class correlation coefficient (ICC) reliability with absolute agreement and analysis of variance model were used to assess reliability of the MEP amplitudes for blocks with variable number of MEPs. RESULTS A decrease in ICC values was observed with removal of 3 or 5 MEPs in both techniques when compared to all MEP responses in any given block. Therefore, removal of the first 3 or 5 MEPs failed to further increase the reliability of MEP responses. CONCLUSION Our findings revealed that a greater number of trials involving averaged MEPs can influence TMS reliability more than removal of the first trials.
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Affiliation(s)
- Fahimeh Hashemirad
- Department of Physiotherapy, School of Primary Health Care, Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Maryam Zoghi
- Department of Medicine at Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, Alfred and Monash University Central Clinical School, Melbourne, Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy, School of Primary Health Care, Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
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Washabaugh EP, Krishnan C. A low-cost system for coil tracking during transcranial magnetic stimulation. Restor Neurol Neurosci 2016; 34:337-46. [PMID: 26923620 DOI: 10.3233/rnn-150609] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE Accurate coil placement over a target area is critical during transcranial magnetic stimulation (TMS), as small deviations can alter testing outcomes. Accordingly, frameless stereotaxic systems (FSS) are recommended for reliable coil placement during TMS applications. However, FSS is not practical due to the cost associated with procuring such systems. Therefore, the purpose of this study was to develop a low-cost TMS coil tracking approach using simple webcams and an image processing algorithm in LabVIEW Vision Assistant. METHODS A system was created using two webcams, retroreflective markers, and computer stereovision, for tracking the TMS coil over a target area. Accuracy of the system was validated in both the global and local reference frames, while repeatability was measured within- and between-days for placement of the TMS coil over the target area relative to the head. The feasibility of our system was also verified by collecting motor evoked potentials (MEPs) of first dorsal interosseous muscle from human subjects. RESULTS The results of this study indicated that the system was highly accurate and repeatable, and could track the coil position with <5 mm error and orientation <1.1° error from the target. We also observed larger and more consistent MEPs when stimulating the brain using feedback from the coil tracking system than when the examiner attempted to stimulate without any feedback. CONCLUSION The findings suggest that webcam-based coil tracking is a feasible low-cost solution to track coil positions during TMS procedures.
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Affiliation(s)
- Edward P Washabaugh
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.,School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
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Rogić Vidaković M, Jerković A, Jurić T, Vujović I, Šoda J, Erceg N, Bubić A, Zmajević Schönwald M, Lioumis P, Gabelica D, Đogaš Z. Neurophysiologic markers of primary motor cortex for laryngeal muscles and premotor cortex in caudal opercular part of inferior frontal gyrus investigated in motor speech disorder: a navigated transcranial magnetic stimulation (TMS) study. Cogn Process 2016; 17:429-442. [PMID: 27130564 DOI: 10.1007/s10339-016-0766-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/18/2016] [Indexed: 11/24/2022]
Abstract
Transcranial magnetic stimulation studies have so far reported the results of mapping the primary motor cortex (M1) for hand and tongue muscles in stuttering disorder. This study was designed to evaluate the feasibility of repetitive navigated transcranial magnetic stimulation (rTMS) for locating the M1 for laryngeal muscle and premotor cortical area in the caudal opercular part of inferior frontal gyrus, corresponding to Broca's area in stuttering subjects by applying new methodology for mapping these motor speech areas. Sixteen stuttering and eleven control subjects underwent rTMS motor speech mapping using modified patterned rTMS. The subjects performed visual object naming task during rTMS applied to the (a) left M1 for laryngeal muscles for recording corticobulbar motor-evoked potentials (CoMEP) from cricothyroid muscle and (b) left premotor cortical area in the caudal opercular part of inferior frontal gyrus while recording long latency responses (LLR) from cricothyroid muscle. The latency of CoMEP in control subjects was 11.75 ± 2.07 ms and CoMEP amplitude was 294.47 ± 208.87 µV, and in stuttering subjects CoMEP latency was 12.13 ± 0.75 ms and 504.64 ± 487.93 µV CoMEP amplitude. The latency of LLR in control subjects was 52.8 ± 8.6 ms and 54.95 ± 4.86 in stuttering subjects. No significant differences were found in CoMEP latency, CoMEP amplitude, and LLR latency between stuttering and control-fluent speakers. These results indicate there are probably no differences in stuttering compared to controls in functional anatomy of the pathway used for transmission of information from premotor cortex to the M1 cortices for laryngeal muscle representation and from there via corticobulbar tract to laryngeal muscles.
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Affiliation(s)
- Maja Rogić Vidaković
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia.
| | - Ana Jerković
- Faculty of Philosophy, University of Zagreb, Ivana Lučića 3, 10000, Zagreb, Croatia
| | - Tomislav Jurić
- Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Department of Electronics, University of Split, R. Boškovića 32, Split, Croatia
| | - Igor Vujović
- Faculty of Maritime Studies, Signal Processing, Analysis and Advanced Diagnostics Research and Education Laboratory (SPAADREL), University of Split, Ruđera-Boškovića 37, Split, Croatia
| | - Joško Šoda
- Faculty of Maritime Studies, Signal Processing, Analysis and Advanced Diagnostics Research and Education Laboratory (SPAADREL), University of Split, Ruđera-Boškovića 37, Split, Croatia
| | - Nikola Erceg
- Faculty of Humanities and Social Sciences, University of Split, Put iza nove bolnice 10 C, Split, Croatia
| | - Andreja Bubić
- Faculty of Humanities and Social Sciences, University of Split, Put iza nove bolnice 10 C, Split, Croatia
| | - Marina Zmajević Schönwald
- Clinical Medical Centre "Sisters of Mercy", Department of Neurosurgery, Clinical Unit for Intraoperative Neurophysiologic Monitoring, Vinogradska 29 A, Zagreb, Croatia
| | - Pantelis Lioumis
- Bio Mag Laboratory HUS Medical Imaging center, Helsinki University Hospital, P.O. Box 340, 00029, HUS, Helsinki, Finland
| | - Dragan Gabelica
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia.,SGM Medical Monitoring, Grge Novaka 22A, 21000, Split, Croatia
| | - Zoran Đogaš
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia
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Goldsworthy M, Hordacre B, Ridding M. Minimum number of trials required for within- and between-session reliability of TMS measures of corticospinal excitability. Neuroscience 2016; 320:205-9. [DOI: 10.1016/j.neuroscience.2016.02.012] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 11/30/2022]
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Repeatability of functional anisotropy in navigated transcranial magnetic stimulation--coil-orientation versus response. Neuroreport 2016; 26:515-21. [PMID: 26011386 DOI: 10.1097/wnr.0000000000000380] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Transcranial magnetic stimulation (TMS) can be used for evaluating the function of motor pathways. According to the principles of electromagnetism and electrophysiology, TMS activates those neurons that are suitably oriented with respect to the TMS-induced electric field. We hypothesized that TMS could potentially be able to evaluate the neuronal structure, although until now, this putative application has not been exploited. We have developed a TMS-based method to evaluate the function and structure of the motor cortex concurrently in a quantitative manner. This method produced a measure, the anisotropy index (AI), which is based on the motor-evoked potentials induced at different coil orientations. The AI was demonstrated to exhibit an association with both motor cortex excitability and neuronal structure. In the present study, we evaluated the repeatability (intrasession and intersession) of AI in three consecutive measurements. In addition, we studied the repeatability of the optimal coil angle in inducing motor-evoked potentials. Two of the measurements were conducted on the same stimulation target and the third on a remapped target. The coefficient of repeatability of the AI was 0.022 for intrasession and 0.040 for intersession assessments. For the optimal stimulation angle, the coefficients of repeatability were 3.7° and 5.1°, respectively. Both the AI and the optimal stimulation angle demonstrated good repeatability (Cronbach's α>0.760). In conclusion, the results indicate that the AI can provide a reliable estimation of local functional anisotropy changes under conditions affecting the cortex, such as during stroke or focal dysplasia.
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Ongoing cumulative effects of single TMS pulses on corticospinal excitability: An intra- and inter-block investigation. Clin Neurophysiol 2016; 127:621-628. [DOI: 10.1016/j.clinph.2015.03.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/04/2015] [Accepted: 03/09/2015] [Indexed: 11/20/2022]
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Woods AJ, Antal A, Bikson M, Boggio PS, Brunoni AR, Celnik P, Cohen LG, Fregni F, Herrmann CS, Kappenman ES, Knotkova H, Liebetanz D, Miniussi C, Miranda PC, Paulus W, Priori A, Reato D, Stagg C, Wenderoth N, Nitsche MA. A technical guide to tDCS, and related non-invasive brain stimulation tools. Clin Neurophysiol 2015; 127:1031-1048. [PMID: 26652115 DOI: 10.1016/j.clinph.2015.11.012] [Citation(s) in RCA: 813] [Impact Index Per Article: 90.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/14/2015] [Accepted: 11/17/2015] [Indexed: 01/29/2023]
Abstract
Transcranial electrical stimulation (tES), including transcranial direct and alternating current stimulation (tDCS, tACS) are non-invasive brain stimulation techniques increasingly used for modulation of central nervous system excitability in humans. Here we address methodological issues required for tES application. This review covers technical aspects of tES, as well as applications like exploration of brain physiology, modelling approaches, tES in cognitive neurosciences, and interventional approaches. It aims to help the reader to appropriately design and conduct studies involving these brain stimulation techniques, understand limitations and avoid shortcomings, which might hamper the scientific rigor and potential applications in the clinical domain.
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Affiliation(s)
- A J Woods
- Center for Cognitive Aging and Memory, Institute on Aging, McKnight Brain Institute, Department of Aging and Geriatric Research, Department of Neuroscience, University of Florida, Gainesville, FL, USA.
| | - A Antal
- University Medical Center, Dept. Clinical Neurophysiology, Georg-August-University, Goettingen, Germany
| | - M Bikson
- Department of Biomedical Engineering, The City College of New York, USA
| | - P S Boggio
- Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program, Center for Health and Biological Science, Mackenzie Presbyterian University, São Paulo, SP, Brazil
| | - A R Brunoni
- Service of Interdisciplinary Neuromodulation, Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - P Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD, USA
| | - L G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - F Fregni
- Laboratory of Neuromodulation, Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard University, USA
| | - C S Herrmann
- Experimental Psychology Lab, Center of excellence Hearing4all, Department for Psychology, Faculty for Medicine and Health Sciences, Carl von Ossietzky Universität, Ammerländer Heerstr, Oldenburg, Germany
| | - E S Kappenman
- Center for Mind & Brain and Department of Psychology, University of California, Davis, CA, USA
| | - H Knotkova
- MJHS Institute for Innovation in Palliative Care, New York, NY, USA
| | - D Liebetanz
- University Medical Center, Dept. Clinical Neurophysiology, Georg-August-University, Goettingen, Germany
| | - C Miniussi
- Neuroscience Section, Department of Clinical and Experimental Sciences, University of Brescia & Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - P C Miranda
- Institute of Biophysics and Biomedical Engineering (IBEB), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - W Paulus
- University Medical Center, Dept. Clinical Neurophysiology, Georg-August-University, Goettingen, Germany
| | - A Priori
- Direttore Clinica Neurologica III, Università degli Studi di Milano, Ospedale San Paolo, Milan, Italy
| | - D Reato
- Department of Biomedical Engineering, The City College of New York, USA
| | - C Stagg
- Centre for Functional MRI of the Brain (FMRIB) Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Centre for Human Brain Activity (OHBA), Department of Psychiatry, University of Oxford, Oxford, UK
| | - N Wenderoth
- Neural Control of Movement Lab, Dept. Health Sciences and Technology, ETH Zürich, Switzerland
| | - M A Nitsche
- University Medical Center, Dept. Clinical Neurophysiology, Georg-August-University, Goettingen, Germany; Leibniz Research Center for Working Environment and Human Factors, Dortmund, Germany; Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Germany
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Consistency of evoked responses to dual-stimulator, single-pulse transcranial magnetic stimulation in the lower limb of people with multiple sclerosis. J Clin Neurosci 2015; 22:1434-7. [DOI: 10.1016/j.jocn.2015.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/21/2015] [Indexed: 11/21/2022]
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Andrews SC, Enticott PG, Hoy KE, Thomson RH, Fitzgerald PB. No evidence for mirror system dysfunction in schizophrenia from a multimodal TMS/EEG study. Psychiatry Res 2015; 228:431-40. [PMID: 26154818 DOI: 10.1016/j.psychres.2015.05.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 05/20/2015] [Accepted: 05/25/2015] [Indexed: 11/26/2022]
Abstract
Dysfunctional mirror neuron systems have been proposed to contribute to the social cognitive deficits observed in schizophrenia. A few studies have explored mirror systems in schizophrenia using various techniques such as TMS (levels of motor resonance) or EEG (levels of mu suppression), with mixed results. This study aimed to use a novel multimodal approach (i.e. concurrent TMS and EEG) to further investigate mirror systems and social cognition in schizophrenia. Nineteen individuals with schizophrenia or schizoaffective disorder and 19 healthy controls participated. Single-pulse TMS was applied to M1 during the observation of hand movements designed to elicit mirror system activity. Single EEG electrodes (C3, CZ, C4) recorded brain activity. Participants also completed facial affect recognition and theory of mind tasks. The schizophrenia group showed significant deficits in facial affect recognition and higher level theory of mind compared to healthy controls. A significant positive relationship was revealed between mu suppression and motor resonance for the overall sample, indicating concurrent validity of these measures. Levels of mu suppression and motor resonance were not significantly different between groups. These findings indicate that in stable outpatients with schizophrenia, mirror system functioning is intact, and therefore their social cognitive difficulties may be caused by alternative pathophysiology.
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Affiliation(s)
- Sophie C Andrews
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia.
| | - Peter G Enticott
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia; Cognitive Neuroscience Unit, School of Psychology, Deakin University, Burwood, Victoria, Australia
| | - Kate E Hoy
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia
| | - Richard H Thomson
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, The Alfred and Central Clinical School Monash University, Melbourne, Victoria, Australia
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Kehrer S, Kraft A, Koch SP, Kathmann N, Irlbacher K, Brandt SA. Timing of spatial priming within the fronto-parietal attention network: A TMS study. Neuropsychologia 2015; 74:30-6. [DOI: 10.1016/j.neuropsychologia.2014.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 11/24/2022]
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The uses and interpretations of the motor-evoked potential for understanding behaviour. Exp Brain Res 2015; 233:679-89. [DOI: 10.1007/s00221-014-4183-7] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 12/09/2014] [Indexed: 12/21/2022]
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How Reproducible Are Transcranial Magnetic Stimulation–Induced MEPs in Subacute Stroke? J Clin Neurophysiol 2014; 31:556-62. [DOI: 10.1097/wnp.0000000000000114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kraft A, Dyrholm M, Kehrer S, Kaufmann C, Bruening J, Kathmann N, Bundesen C, Irlbacher K, Brandt SA. TMS over the right precuneus reduces the bilateral field advantage in visual short term memory capacity. Brain Stimul 2014; 8:216-23. [PMID: 25481073 DOI: 10.1016/j.brs.2014.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 10/21/2014] [Accepted: 11/06/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Several studies have demonstrated a bilateral field advantage (BFA) in early visual attentional processing, that is, enhanced visual processing when stimuli are spread across both visual hemifields. The results are reminiscent of a hemispheric resource model of parallel visual attentional processing, suggesting more attentional resources on an early level of visual processing for bilateral displays [e.g. Sereno AB, Kosslyn SM. Discrimination within and between hemifields: a new constraint on theories of attention. Neuropsychologia 1991;29(7):659-75.]. Several studies have shown that the BFA extends beyond early stages of visual attentional processing, demonstrating that visual short term memory (VSTM) capacity is higher when stimuli are distributed bilaterally rather than unilaterally. OBJECTIVE/HYPOTHESIS Here we examine whether hemisphere-specific resources are also evident on later stages of visual attentional processing. METHODS Based on the Theory of Visual Attention (TVA) [Bundesen C. A theory of visual attention. Psychol Rev 1990;97(4):523-47.] we used a whole report paradigm that allows investigating visual attention capacity variability in unilateral and bilateral displays during navigated repetitive transcranial magnetic stimulation (rTMS) of the precuneus region. RESULTS A robust BFA in VSTM storage capacity was apparent after rTMS over the left precuneus and in the control condition without rTMS. In contrast, the BFA diminished with rTMS over the right precuneus. CONCLUSION This finding indicates that the right precuneus plays a causal role in VSTM capacity, particularly in bilateral visual displays.
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Affiliation(s)
- Antje Kraft
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany; Berlin Institute of Health, Charité Universitätsmedizin Berlin, Berlin, Germany.
| | - Mads Dyrholm
- Center of Visual Cognition, Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Stefanie Kehrer
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Christian Kaufmann
- Clinical Psychology, Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jovita Bruening
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Norbert Kathmann
- Clinical Psychology, Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Claus Bundesen
- Center of Visual Cognition, Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Kerstin Irlbacher
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Stephan A Brandt
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
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Kuppuswamy A, Clark EV, Turner IF, Rothwell JC, Ward NS. Post-stroke fatigue: a deficit in corticomotor excitability? ACTA ACUST UNITED AC 2014; 138:136-48. [PMID: 25367024 DOI: 10.1093/brain/awu306] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The pathophysiology of post-stroke fatigue is poorly understood although it is thought to be a consequence of central nervous system pathophysiology. In this study we investigate the relationship between corticomotor excitability and self-reported non-exercise related fatigue in chronic stroke population. Seventy first-time non-depressed stroke survivors (60.36 ± 12.4 years, 20 females, 56.81 ± 63 months post-stroke) with minimal motor and cognitive impairment were included in the cross-sectional observational study. Fatigue was measured using two validated questionnaires: Fatigue Severity Scale 7 and Neurological Fatigue Index - Stroke. Perception of effort was measured using a 0-10 numerical rating scale in an isometric biceps hold-task and was used as a secondary measure of fatigue. Neurophysiological measures of corticomotor excitability were performed using transcranial magnetic stimulation. Corticospinal excitability was quantified using resting and active motor thresholds and stimulus-response curves of the first dorsal interosseous muscle. Intracortical M1 excitability was measured using paired pulse paradigms: short and long interval intracortical inhibition in the same hand muscle as above. Excitability of cortical and subcortical inputs that drive M1 output was measured in the biceps muscle using a modified twitch interpolation technique to provide an index of central activation failure. Stepwise regression was performed to determine the explanatory variables that significantly accounted for variance in the fatigue and perception scores. Resting motor threshold (R = 0.384; 95% confidence interval = 0.071; P = 0.036) accounted for 14.7% (R(2)) of the variation in Fatigue Severity Scale 7. Central activation failure (R = 0.416; 95% confidence interval = -1.618; P = 0.003) accounted for 17.3% (R(2)) of the variation in perceived effort score. Thus chronic stroke survivors with high fatigue exhibit high motor thresholds and those who perceive high effort have low excitability of inputs that drive motor cortex output. We suggest that low excitability of both corticospinal output and its facilitatory synaptic inputs from cortical and sub-cortical sites contribute to high levels of fatigue after stroke.
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Affiliation(s)
| | - Ella V Clark
- Sobell Department of Motor Neuroscience, Institute of Neurology, UCL, London, UK
| | - Isobel F Turner
- Sobell Department of Motor Neuroscience, Institute of Neurology, UCL, London, UK
| | - John C Rothwell
- Sobell Department of Motor Neuroscience, Institute of Neurology, UCL, London, UK
| | - Nick S Ward
- Sobell Department of Motor Neuroscience, Institute of Neurology, UCL, London, UK
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Neurophysiologic markers in laryngeal muscles indicate functional anatomy of laryngeal primary motor cortex and premotor cortex in the caudal opercular part of inferior frontal gyrus. Clin Neurophysiol 2014; 125:1912-22. [DOI: 10.1016/j.clinph.2014.01.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 11/23/2022]
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Schmidt S, Bathe-Peters R, Fleischmann R, Rönnefarth M, Scholz M, Brandt SA. Nonphysiological factors in navigated TMS studies; confounding covariates and valid intracortical estimates. Hum Brain Mapp 2014; 36:40-9. [PMID: 25168635 DOI: 10.1002/hbm.22611] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 11/09/2022] Open
Abstract
UNLABELLED Brain stimulation is used to induce transient alterations of neural excitability to probe or modify brain function. For example, single-pulse transcranial magnetic stimulation (TMS) of the motor cortex can probe corticospinal excitability (CSE). Yet, CSE measurements are confounded by a high level of variability. This variability is due to physical and physiological factors. Navigated TMS (nTMS) systems can record physical parameters of the TMS coil (tilt, location, and orientation) and some also estimate intracortical electric fields (EFs) on a trial-by-trial basis. Thus, these parameters can be partitioned with stepwise regression. PURPOSE The primary objective was to dissociate variance due to physical parameters from variance due to physiological factors for CSE estimates. The secondary objective was to establish the predictive validity of EF estimates from spherical head models. HYPOTHESIS Variability of physical parameters of TMS predicts CSE variability. METHODS Event-related measurements of physical parameters were analyzed in stepwise regression. Partitioned parameter variance and predictive validity were compared for a target-controlled and a nontarget-controlled experiment. A control experiment (preinnervation) confirmed the validity of linear data analysis. A bias-free model quantified the effect of divergence from optimum. RESULTS Partitioning physical parameter variance reduces CSE variability. EF estimates from spherical models were valid. Post hoc analyses showed that even small physical fluctuations can confound the statistical comparison of CSE measurements. CONCLUSIONS It is necessary to partition physical and physiological variance in TMS studies to make confounded data interpretable. The spatial resolution of nTMS is <5 mm and the EF-estimates are valid.
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Affiliation(s)
- Sein Schmidt
- Vision & Motor Research Group, Department of Neurology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany
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Rogić M, Deletis V, Fernández-Conejero I. Inducing transient language disruptions by mapping of Broca's area with modified patterned repetitive transcranial magnetic stimulation protocol. J Neurosurg 2014; 120:1033-41. [DOI: 10.3171/2013.11.jns13952] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Until now there has been no reliable stimulation protocol for inducing transient language disruptions while mapping Broca's area. Despite the promising data of only a few studies in which speech arrest and language disturbances have been induced, certain concerns have been raised. The purpose of this study was to map Broca's area by using event-related navigated transcranial magnetic stimulation (nTMS) to generate a modified patterned nTMS protocol.
Methods
Eleven right-handed subjects underwent nTMS to Broca's area while engaged in a visual object-naming task. Navigated TMS was triggered 300 msec after picture presentation. The modified patterned nTMS protocol consists of 4 stimuli with an interstimulus interval of 6 msec; 8 or 16 of those bursts were repeated with a burst repetition rate of 12 Hz. Prior to mapping of Broca's area, the primary motor cortices (M1) for hand and laryngeal muscles were mapped. The Euclidian distance on MRI was measured between cortical points eliciting transient language disruptions and M1 for the laryngeal muscle.
Results
On stimulating Broca's area, transient language disruptions were induced in all subjects. The mean Euclidian distance between cortical spots inducing transient language disruptions and M1 for the laryngeal muscle was 17.23 ± 4.73 mm.
Conclusions
The stimulation paradigm with the modified patterned nTMS protocol was shown to be promising and might gain more widespread use in speech localization in clinical and research applications.
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Affiliation(s)
- Maja Rogić
- 1Laboratory for Human and Experimental Neurophysiology, School of Medicine, University of Split, Croatia
| | - Vedran Deletis
- 1Laboratory for Human and Experimental Neurophysiology, School of Medicine, University of Split, Croatia
- 2Department for Intraoperative Neurophysiology, Roosevelt Hospital, New York, New York; and
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