1
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Klees-Themens G, Théoret H. The effects of transcranial direct current stimulation on corticospinal excitability: A systematic review of nonsignificant findings. Eur J Neurosci 2023; 58:3074-3097. [PMID: 37407275 DOI: 10.1111/ejn.16073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 07/07/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that can modulate brain activity through the application of low-intensity electrical currents. Based on its reported effects on corticospinal excitability (CSE), tDCS has been used to study cognition in healthy individuals and reduce symptoms in a variety of clinical conditions. Despite its increasing popularity as a research and clinical tool, high interindividual variability has been reported in the response to protocols using transcranial magnetic stimulation (TMS) to assess tDCS-induced changes in CSE leading to several nonsignificant findings. In this systematic review, studies that reported no significant modulation of CSE following tDCS were identified from PubMed and Embase (Ovid) databases. Forty-three articles were identified where demographic, TMS and tDCS parameters were extracted. Overall, stimulation parameters, CSE measurements and participant characteristics were similar to those described in studies reporting positive results and were likewise heterogeneous between studies. Small sample sizes and inadequate blinding were notable features of the reviewed studies. This systematic review suggests that studies reporting nonsignificant findings do not markedly differ from those reporting significant modulation of CSE.
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Affiliation(s)
| | - Hugo Théoret
- Department of Psychology, Université de Montréal, Montreal, Québec, Canada
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2
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Ma W, Nemdharry S, Elgueta Cancino E, Chiou SY. Influence of coil orientation on corticospinal excitability of trunk muscles during postural and volitional tasks in healthy adults. Front Hum Neurosci 2023; 17:1108169. [PMID: 36816500 PMCID: PMC9929149 DOI: 10.3389/fnhum.2023.1108169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/16/2023] [Indexed: 02/04/2023] Open
Abstract
Introduction Trunk muscles play a role in maintaining postural stability and performing goal-directed voluntary movements in activities of daily living. Evidence has shown that the primary motor cortex (M1) is involved in modulation of postural control and voluntary movements of the trunk. However, it remains unknown whether the neural circuits within the M1 were recruited to the same extent between a postural task and a goal-directed voluntary task. Methods To address this, we examined latencies and amplitudes of motor evoked potentials (MEPs) of the erector spinae (ES) with transcranial magnetic stimulation (TMS) figure-of-eight coil oriented to induce latero-medial (LM), posterior-anterior (PA), and anterior-posterior (AP) currents in the M1 in twenty healthy participants during a dynamic shoulder flexion (DSF) task, a postural task requiring anticipatory postural adjustments (APAs), and during a static trunk extension (STE) task, a voluntary task without involvement of APAs. Results We found that differences in the AP-LM latency of ES MEP were longer compared with the PA-LM latency in both tasks. Corticospinal excitability was overall greater during the DSF task than during the STE task irrespective of the coil orientation. Discussion Our findings suggest that while the same neural circuits in the M1 were recruited to modulate both postural and voluntary control of the trunk, the contribution was greater to the postural task than the voluntary task, possibly due to the requirement of APAs in the task.
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Affiliation(s)
- Wesley Ma
- School of Sport, Exercise and Rehabilitation Science, University of Birmingham, Birmingham, United Kingdom
| | - Sheanil Nemdharry
- School of Sport, Exercise and Rehabilitation Science, University of Birmingham, Birmingham, United Kingdom
| | - Edith Elgueta Cancino
- School of Sport, Exercise and Rehabilitation Science, University of Birmingham, Birmingham, United Kingdom,Exercise and Rehabilitation Sciences Institute, School of Physical Therapy, Faculty of Rehabilitation Science, Universidad Andrés Bello, Santiago, Chile
| | - Shin-Yi Chiou
- School of Sport, Exercise and Rehabilitation Science, University of Birmingham, Birmingham, United Kingdom,*Correspondence: Shin-Yi Chiou ✉
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3
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Neige C, Ciechelski V, Lebon F. The recruitment of indirect waves within primary motor cortex during motor imagery: A directional transcranial magnetic stimulation study. Eur J Neurosci 2022; 56:6187-6200. [PMID: 36215136 PMCID: PMC10092871 DOI: 10.1111/ejn.15843] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/15/2022] [Accepted: 09/28/2022] [Indexed: 12/29/2022]
Abstract
Motor imagery (MI) refers to the mental simulation of an action without overt movement. While numerous transcranial magnetic stimulation (TMS) studies provided evidence for a modulation of corticospinal excitability and intracortical inhibition during MI, the neural signature within the primary motor cortex is not clearly established. In the current study, we used directional TMS to probe the modulation of the excitability of early and late indirect waves (I-waves) generating pathways during MI. Corticospinal responses evoked by TMS with posterior-anterior (PA) and anterior-posterior (AP) current flow within the primary motor cortex evoke preferentially early and late I-waves, respectively. Seventeen participants were instructed to stay at rest or to imagine maximal isometric contractions of the right flexor carpi radialis. We demonstrated that the increase of corticospinal excitability during MI is greater with PA than AP orientation. By using paired-pulse stimulations, we confirmed that short-interval intracortical inhibition (SICI) increased during MI in comparison to rest with PA orientation, whereas we found that it decreased with AP orientation. Overall, these results indicate that the pathways recruited by PA and AP orientations that generate early and late I-waves are differentially modulated by MI.
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Affiliation(s)
- Cécilia Neige
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France.,Centre Hospitalier Le Vinatier, Université Claude Bernard Lyon 1, INSERM, CNRS, CRNL U1028 UMR5292, PsyR2 Team, Bron, France
| | - Valentin Ciechelski
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Florent Lebon
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
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4
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Key factors in the cortical response to transcranial electrical Stimulations—A multi-scale modeling study. Comput Biol Med 2022; 144:105328. [DOI: 10.1016/j.compbiomed.2022.105328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/26/2022] [Accepted: 02/14/2022] [Indexed: 11/24/2022]
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5
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Pate JW, McCambridge AB. Single Case Experimental Design: A New Approach for Non-invasive Brain Stimulation Research? FRONTIERS IN NEUROERGONOMICS 2021; 2:678579. [PMID: 38235212 PMCID: PMC10790913 DOI: 10.3389/fnrgo.2021.678579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/10/2021] [Indexed: 01/19/2024]
Affiliation(s)
| | - Alana B. McCambridge
- Graduate School of Health, Discipline of Physiotherapy, University of Technology Sydney, Sydney, NSW, Australia
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6
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Hordacre B, McCambridge AB, Ridding MC, Bradnam LV. Can Transcranial Direct Current Stimulation Enhance Poststroke Motor Recovery? Development of a Theoretical Patient-Tailored Model. Neurology 2021; 97:170-180. [PMID: 33986136 DOI: 10.1212/wnl.0000000000012187] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/29/2021] [Indexed: 12/21/2022] Open
Abstract
New treatments that can facilitate neural repair and reduce persistent impairments have significant value in promoting recovery following stroke. One technique that has gained interest is transcranial direct current stimulation (tDCS) as early research suggested it could enhance plasticity and enable greater behavioral recovery. However, several studies have now identified substantial intersubject variability in response to tDCS and clinical trials revealed insufficient evidence of treatment effectiveness. A possible explanation for the varied and negative findings is that the physiologic model of stroke recovery that researchers have used to guide the application of tDCS-based treatments in stroke is overly simplistic and does not account for stroke heterogeneity or known determinants that affect the tDCS response. Here, we propose that tDCS could have a more clearly beneficial role in enhancing stroke recovery if greater consideration is given to individualizing treatment. By critically reviewing the proposed mechanisms of tDCS, stroke physiology across the recovery continuum, and known determinants of tDCS response, we propose a new, theoretical, patient-tailored approach to delivering tDCS after stroke. The proposed model includes a step-by-step principled selection strategy for identifying optimal neuromodulation targets and outlines key areas for further investigation. Tailoring tDCS treatment to individual neuroanatomy and physiology is likely our best chance at producing robust and meaningful clinical benefit for people with stroke and would therefore accelerate opportunities for clinical translation.
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Affiliation(s)
- Brenton Hordacre
- From Innovation, Implementation and Clinical Translation in Health (IIMPACT in Health) (B.H., M.C.R.), Allied Health and Human Performance Academic Unit, University of South Australia, Adelaide; Graduate School of Health, Discipline of Physiotherapy (A.B.M.), University of Technology Sydney, Australia; and Department of Exercise Sciences (L.V.B.), University of Auckland, New Zealand.
| | - Alana B McCambridge
- From Innovation, Implementation and Clinical Translation in Health (IIMPACT in Health) (B.H., M.C.R.), Allied Health and Human Performance Academic Unit, University of South Australia, Adelaide; Graduate School of Health, Discipline of Physiotherapy (A.B.M.), University of Technology Sydney, Australia; and Department of Exercise Sciences (L.V.B.), University of Auckland, New Zealand
| | - Michael C Ridding
- From Innovation, Implementation and Clinical Translation in Health (IIMPACT in Health) (B.H., M.C.R.), Allied Health and Human Performance Academic Unit, University of South Australia, Adelaide; Graduate School of Health, Discipline of Physiotherapy (A.B.M.), University of Technology Sydney, Australia; and Department of Exercise Sciences (L.V.B.), University of Auckland, New Zealand
| | - Lynley V Bradnam
- From Innovation, Implementation and Clinical Translation in Health (IIMPACT in Health) (B.H., M.C.R.), Allied Health and Human Performance Academic Unit, University of South Australia, Adelaide; Graduate School of Health, Discipline of Physiotherapy (A.B.M.), University of Technology Sydney, Australia; and Department of Exercise Sciences (L.V.B.), University of Auckland, New Zealand
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7
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Opie GM, Liao WY, Semmler JG. Interactions Between Cerebellum and the Intracortical Excitatory Circuits of Motor Cortex: a Mini-Review. CEREBELLUM (LONDON, ENGLAND) 2021; 21:159-166. [PMID: 33978934 DOI: 10.1007/s12311-021-01278-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 05/03/2021] [Indexed: 12/28/2022]
Abstract
Interactions between cerebellum (CB) and primary motor cortex (M1) are critical for effective motor function. Although the associated neurophysiological processes are yet to be fully characterised, a growing body of work using non-invasive brain stimulation (NIBS) techniques has significantly progressed our current understanding. In particular, recent developments with both transcranial magnetic (TMS) and direct current (tDCS) stimulation suggest that CB modulates the activity of local excitatory interneuronal circuits within M1. These circuits are known to be important both physiologically and functionally, and understanding the nature of their connectivity with CB therefore has the potential to provide important insight for NIBS applications. Consequently, this mini-review provides an overview of the emerging literature that has investigated interactions between CB and the intracortical excitatory circuits of M1.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Wei-Yeh Liao
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia.
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Karabanov AN, Shindo K, Shindo Y, Raffin E, Siebner HR. Multimodal Assessment of Precentral Anodal TDCS: Individual Rise in Supplementary Motor Activity Scales With Increase in Corticospinal Excitability. Front Hum Neurosci 2021; 15:639274. [PMID: 33762917 PMCID: PMC7982814 DOI: 10.3389/fnhum.2021.639274] [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: 12/08/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Background Transcranial direct current stimulation (TDCS) targeting the primary motor hand area (M1-HAND) may induce lasting shifts in corticospinal excitability, but after-effects show substantial inter-individual variability. Functional magnetic resonance imaging (fMRI) can probe after-effects of TDCS on regional neural activity on a whole-brain level. Objective Using a double-blinded cross-over design, we investigated whether the individual change in corticospinal excitability after TDCS of M1-HAND is associated with changes in task-related regional activity in cortical motor areas. Methods Seventeen healthy volunteers (10 women) received 20 min of real (0.75 mA) or sham TDCS on separate days in randomized order. Real and sham TDCS used the classic bipolar set-up with the anode placed over right M1-HAND. Before and after each TDCS session, we recorded motor evoked potentials (MEP) from the relaxed left first dorsal interosseus muscle after single-pulse transcranial magnetic stimulation(TMS) of left M1-HAND and performed whole-brain fMRI at 3 Tesla while participants completed a visuomotor tracking task with their left hand. We also assessed the difference in MEP latency when applying anterior-posterior and latero-medial TMS pulses to the precentral hand knob (AP-LM MEP latency). Results Real TDCS had no consistent aftereffects on mean MEP amplitude, task-related activity or motor performance. Individual changes in MEP amplitude, measured directly after real TDCS showed a positive linear relationship with individual changes in task-related activity in the supplementary motor area and AP-LM MEP latency. Conclusion Functional aftereffects of classical bipolar anodal TDCS of M1-HAND on the motor system vary substantially across individuals. Physiological features upstream from the primary motor cortex may determine how anodal TDCS changes corticospinal excitability.
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Affiliation(s)
- Anke Ninija Karabanov
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Keiichiro Shindo
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjyuku-ku, Japan
| | - Yuko Shindo
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjyuku-ku, Japan
| | - Estelle Raffin
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology, Geneva, Switzerland
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
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9
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Modulation of Motor Cortex Plasticity by Repetitive Paired-Pulse TMS at Late I-Wave Intervals Is Influenced by Intracortical Excitability. Brain Sci 2021; 11:brainsci11010121. [PMID: 33477434 PMCID: PMC7829868 DOI: 10.3390/brainsci11010121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 01/28/2023] Open
Abstract
The late indirect (I)-waves recruited by transcranial magnetic stimulation (TMS) over primary motor cortex (M1) can be modulated using I-wave periodicity repetitive TMS (iTMS). The purpose of this study was to determine if the response to iTMS is influenced by different interstimulus intervals (ISIs) targeting late I-waves, and whether these responses were associated with individual variations in intracortical excitability. Seventeen young (27.2 ± 6.4 years, 12 females) healthy adults received iTMS at late I-wave intervals (4.0, 4.5, and 5.0 ms) in three separate sessions. Changes due to each intervention were examined with motor evoked potential (MEP) amplitudes and short-interval intracortical facilitation (SICF) using both posterior-anterior (PA) and anterior-posterior (AP) TMS current directions. Changes in MEP amplitude and SICF were influenced by iTMS ISI, with the greatest facilitation for ISIs at 4 and 5 ms with PA TMS, and 4 ms with AP TMS. Maximum SICF at baseline (irrespective of ISI) was associated with increased iTMS response, but only for PA stimulation. These results suggest that modifying iTMS parameters targeting late I-waves can influence M1 plasticity. They also suggest that maximum SICF may be a means by which responders to iTMS targeting the late I-waves could be identified.
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10
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Opie GM, Semmler JG. Preferential Activation of Unique Motor Cortical Networks With Transcranial Magnetic Stimulation: A Review of the Physiological, Functional, and Clinical Evidence. Neuromodulation 2020; 24:813-828. [PMID: 33295685 DOI: 10.1111/ner.13314] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/30/2020] [Accepted: 10/19/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The corticospinal volley produced by application of transcranial magnetic stimulation (TMS) over primary motor cortex consists of a number of waves generated by trans-synaptic input from interneuronal circuits. These indirect (I)-waves mediate the sensitivity of TMS to cortical plasticity and intracortical excitability and can be assessed by altering the direction of cortical current induced by TMS. While this methodological approach has been conventionally viewed as preferentially recruiting early or late I-wave inputs from a given populations of neurons, growing evidence suggests recruitment of different neuronal populations, and this would strongly influence interpretation and application of these measures. The aim of this review is therefore to consider the physiological, functional, and clinical evidence for the independence of the neuronal circuits activated by different current directions. MATERIALS AND METHODS To provide the relevant context, we begin with an overview of TMS methodology, focusing on the different techniques used to quantify I-waves. We then comprehensively review the literature that has used variations in coil orientation to investigate the I-wave circuits, grouping studies based on the neurophysiological, functional, and clinical relevance of their outcomes. RESULTS Review of the existing literature reveals significant evidence supporting the idea that varying current direction can recruit different neuronal populations having unique functionally and clinically relevant characteristics. CONCLUSIONS Further research providing greater characterization of the I-wave circuits activated with different current directions is required. This will facilitate the development of interventions that are able to modulate specific intracortical circuits, which will be an important application of TMS.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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11
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Pellegrini M, Zoghi M, Jaberzadeh S. A Checklist to Reduce Response Variability in Studies Using Transcranial Magnetic Stimulation for Assessment of Corticospinal Excitability: A Systematic Review of the Literature. Brain Connect 2020; 10:53-71. [PMID: 32093486 DOI: 10.1089/brain.2019.0715] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Response variability between individuals (interindividual variability) and within individuals (intraindividual variability) is an important issue in the transcranial magnetic stimulation (TMS) literature. This has raised questions of the validity of TMS to assess changes in corticospinal excitability (CSE) in a predictable and reliable manner. Several participant-specific factors contribute to this observed response variability with a current lack of consensus on the degree each factor contributes. This highlights a need for consistency and structure in reporting study designs and methodologies. Currently, there is no summarized review of the participant-specific factors that can be controlled and may contribute to response variability. This systematic review aimed to develop a checklist of methodological measures taken by previously published research to increase the homogeneity of participant selection criteria, preparation of participants before experimental testing, participant scheduling, and the instructions given to participants throughout experimental testing to minimize their effect on response variability. Seven databases were searched in full. Studies were included if CSE was measured via TMS and included methodological measures to increase the homogeneity of the participants. Eighty-four studies were included. Twenty-three included measures to increase participant selection homogeneity, 21 included measures to increase participant preparation homogeneity, while 61 included measures to increase participant scheduling and instructions during experimental testing homogeneity. These methodological measures were summarized into a user-friendly checklist with considerations, suggestions, and rationale/justification for their inclusion. This may provide the framework for further insights into ways to reduce response variability in TMS research.
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Affiliation(s)
- Michael Pellegrini
- Non-Invasive 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, Victoria, Australia
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, Discipline of Physiotherapy, School of Allied Health, La Trobe University, Melbourne, Victoria, Australia
| | - Shapour Jaberzadeh
- Non-Invasive 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, Victoria, Australia
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12
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Kuo IJ, Tang CW, Tsai YA, Tang SC, Lin CJ, Hsu SP, Liang WK, Juan CH, Zich C, Stagg CJ, Lee IH. Neurophysiological signatures of hand motor response to dual-transcranial direct current stimulation in subacute stroke: a TMS and MEG study. J Neuroeng Rehabil 2020; 17:72. [PMID: 32527268 PMCID: PMC7291576 DOI: 10.1186/s12984-020-00706-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/01/2020] [Indexed: 11/11/2022] Open
Abstract
Background Dual transcranial direct current stimulation (tDCS) to the bilateral primary motor cortices (M1s) has potential benefits in chronic stroke, but its effects in subacute stroke, when behavioural effects might be expected to be greater, have been relatively unexplored. Here, we examined the neurophysiological effects and the factors influencing responsiveness of dual-tDCS in subacute stroke survivors. Methods We conducted a randomized sham-controlled crossover study in 18 survivors with first-ever, unilateral subcortical ischaemic stroke 2–4 weeks after stroke onset and 14 matched healthy controls. Participants had real dual-tDCS (with an ipsilesional [right for controls] M1 anode and a contralesional M1 [left for controls] cathode; 2 mA for 20mins) and sham dual-tDCS on separate days, with concurrent paretic [left for controls] hand exercise. Using transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG), we recorded motor evoked potentials (MEPs), the ipsilateral silent period (iSP), short-interval intracortical inhibition, and finger movement-related cortical oscillations before and immediately after tDCS. Results Stroke survivors had decreased excitability in ipsilesional M1 with a relatively excessive transcallosal inhibition from the contralesional to ipsilesional hemisphere at baseline compared with controls, as quantified by decreased MEPs and increased iSP duration. Dual-tDCS led to increased MEPs and decreased iSP duration in ipsilesional M1. The magnitude of the tDCS-induced MEP increase in stroke survivors was predicted by baseline contralesional-to-ipsilesional transcallosal inhibition (iSP) ratio. Baseline post-movement synchronization in α-band activity in ipsilesional M1 was decreased after stroke compared with controls, and its tDCS-induced increase correlated with upper limb score in stroke survivors. No significant adverse effects were observed during or after dual-tDCS. Conclusions Task-concurrent dual-tDCS in subacute stroke can safely and effectively modulate bilateral M1 excitability and inter-hemispheric imbalance and also movement-related α-activity.
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Affiliation(s)
- I-Ju Kuo
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Chih-Wei Tang
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Department of Neurology, Far Eastern Memorial Hospital, No.21, Sec. 2, Nanya S. Rd., Banqiao Dist, New Taipei City, 220, Taiwan
| | - Yun-An Tsai
- Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Shuen-Chang Tang
- Department of Neurosurgery, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Chun-Jen Lin
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan.,Division of Cerebrovascular Diseases, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan
| | - Shih-Pin Hsu
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, No.300, Zhongda Rd., Zhongli Dist, Taoyuan City, 320, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, No.300, Zhongda Rd., Zhongli Dist, Taoyuan City, 320, Taiwan
| | - Catharina Zich
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK.,Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, OX3 7JX, UK.,MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - Charlotte J Stagg
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK.,Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, OX3 7JX, UK.,MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - I-Hui Lee
- Institute of Brain Science, Brain Research Center, National Yang-Ming University, No.155, Sec. 2, Linong St., Beitou Dist, Taipei City, 112, Taiwan. .,Division of Cerebrovascular Diseases, Neurological Institute, Taipei Veterans General Hospital, No.201, Sec. 2, Shipai Rd., Beitou Dist, Taipei City, 112, Taiwan.
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13
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Gowan S, Hordacre B. Transcranial Direct Current Stimulation to Facilitate Lower Limb Recovery Following Stroke: Current Evidence and Future Directions. Brain Sci 2020; 10:brainsci10050310. [PMID: 32455671 PMCID: PMC7287858 DOI: 10.3390/brainsci10050310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 12/30/2022] Open
Abstract
Stroke remains a global leading cause of disability. Novel treatment approaches are required to alleviate impairment and promote greater functional recovery. One potential candidate is transcranial direct current stimulation (tDCS), which is thought to non-invasively promote neuroplasticity within the human cortex by transiently altering the resting membrane potential of cortical neurons. To date, much work involving tDCS has focused on upper limb recovery following stroke. However, lower limb rehabilitation is important for regaining mobility, balance, and independence and could equally benefit from tDCS. The purpose of this review is to discuss tDCS as a technique to modulate brain activity and promote recovery of lower limb function following stroke. Preliminary evidence from both healthy adults and stroke survivors indicates that tDCS is a promising intervention to support recovery of lower limb function. Studies provide some indication of both behavioral and physiological changes in brain activity following tDCS. However, much work still remains to be performed to demonstrate the clinical potential of this neuromodulatory intervention. Future studies should consider treatment targets based on individual lesion characteristics, stage of recovery (acute vs. chronic), and residual white matter integrity while accounting for known determinants and biomarkers of tDCS response.
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Affiliation(s)
- Samuel Gowan
- Interdisciplinary Neuroscience Program, Department of Biology, University of Wisconsin—La Crosse, La Crosse, WI 54601, USA
- Correspondence: ; Tel.: +61-8-83021286
| | - Brenton Hordacre
- IIMPACT in Health, University of South Australia, Adelaide, SA 5001, Australia;
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14
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Volz LJ, Hamada M, Michely J, Pool EM, Nettekoven C, Rothwell JC, Grefkes Hermann C. Modulation of I-wave generating pathways by theta-burst stimulation: a model of plasticity induction. J Physiol 2019; 597:5963-5971. [PMID: 31647123 DOI: 10.1113/jp278636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/11/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Mechanisms underlying plasticity induction by repetitive transcranial magnetic stimulation protocols such as intermittent theta-burst stimulation (iTBS) remain poorly understood. Individual response to iTBS is associated with recruitment of late indirect wave (I-wave) generating pathways that can be probed by the onset latency of transcranial magnetic stimulation applied to primary motor cortex (M1) at different coil orientations. We found an association between late I-wave recruitment [reflected by anterior-posterior (AP)-lateromedial (LM) latency; i.e. the excess latency of motor-evoked potentials generated by transcranial magnetic stimulation with an AP orientation over the latency of motor-evoked potentials evoked by direct activation of corticospinal axons using LM stimulation] and changes in cortical excitability following iTBS, confirming previous studies. AP-LM latency significantly decreased following iTBS, and this decrease correlated with the iTBS-induced increase in cortical excitability across subjects. Plasticity in the motor network may in part derive from a modulation of excitability and the recruitment of late I-wave generating cortical pathways. ABSTRACT Plasticity-induction following theta burst transcranial stimulation (TBS) varies considerably across subjects, and the underlying neurophysiological mechanisms remain poorly understood, representing a challenge for scientific and clinical applications. In human motor cortex (M1), recruitment of indirect waves (I-waves) can be probed by the excess latency of motor-evoked potentials elicited by transcranial magnetic stimulation with an anterior-posterior (AP) orientation over the latency of motor-evoked potentials evoked by direct activation of corticospinal axons using lateromedial (LM) stimulation, referred to as the 'AP-LM latency' difference. Importantly, AP-LM latency has been shown to predict individual responses to TBS across subjects. We, therefore, hypothesized that the plastic changes in corticospinal excitability induced by TBS are the result, at least in part, of changes in excitability of these same I-wave generating pathways. In 20 healthy subjects, we investigated whether intermittent TBS (iTBS) modulates I-wave recruitment as reflected by changes in the AP-LM latency. As expected, we found that AP-LM latencies before iTBS were associated with iTBS-induced excitability changes. A novel finding was that iTBS reduced AP-LM latency, and that this reduction significantly correlated with changes in cortical excitability observed following iTBS: subjects with larger reductions in AP-LM latencies featured larger increases in cortical excitability following iTBS. Our findings suggest that plasticity-induction by iTBS may derive from the modulation of I-wave generating pathways projecting onto M1, accounting for the predictive potential of I-wave recruitment. The excitability of I-wave generating pathways may serve a critical role in modulating motor cortical excitability and hence represent a promising target for novel repetitive transcranial magnetic stimulation protocols.
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Affiliation(s)
- Lukas J Volz
- Medical Faculty, University of Cologne & Department of Neurology, University Hospital Cologne, Germany.,Institute for Neuroscience and Medicine (INM-3), Research Center Jülich, Germany
| | - Masashi Hamada
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurology, The University of Tokyo, Japan
| | - Jochen Michely
- Medical Faculty, University of Cologne & Department of Neurology, University Hospital Cologne, Germany.,Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, UK
| | - Eva-Maria Pool
- Medical Faculty, University of Cologne & Department of Neurology, University Hospital Cologne, Germany.,Institute for Neuroscience and Medicine (INM-3), Research Center Jülich, Germany
| | - Charlotte Nettekoven
- Institute for Neuroscience and Medicine (INM-3), Research Center Jülich, Germany
| | - John C Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Christian Grefkes Hermann
- Medical Faculty, University of Cologne & Department of Neurology, University Hospital Cologne, Germany.,Institute for Neuroscience and Medicine (INM-3), Research Center Jülich, Germany
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15
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Alder G, Signal N, Olsen S, Taylor D. A Systematic Review of Paired Associative Stimulation (PAS) to Modulate Lower Limb Corticomotor Excitability: Implications for Stimulation Parameter Selection and Experimental Design. Front Neurosci 2019; 13:895. [PMID: 31507367 PMCID: PMC6718871 DOI: 10.3389/fnins.2019.00895] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022] Open
Abstract
Non-invasive neuromodulatory interventions have the potential to influence neural plasticity and augment motor rehabilitation in people with stroke. Paired associative stimulation (PAS) involves the repeated pairing of single pulses of electrical stimulation to a peripheral nerve and single pulses of transcranial magnetic stimulation over the contralateral primary motor cortex. Efficacy of PAS in the lower limb of healthy and stroke populations has not been systematically appraised. Optimal protocols including stimulation parameter settings have yet to be determined. This systematic review (a) examines the efficacy of PAS on lower limb corticomotor excitability in healthy and stroke populations and (b) evaluates the stimulation parameters employed. Five databases were searched for randomized, non-randomized, and pre-post experimental studies evaluating lower limb PAS in healthy and stroke populations. Two independent reviewers identified eligible studies and assessed methodological quality using a modified Downs and Blacks Tool and the TMS Checklist. Intervention stimulation parameters and TMS measurement details were also extracted and compared. Twelve articles, comprising 24 experiments, met the inclusion criteria. Four articles evaluated PAS in people with stroke. Following a single session of PAS, 21 experiments reported modulation of corticomotor excitability, lasting up to 60 min; however, the research lacked methodological rigor. Intervention stimulation parameters were highly variable across experiments, and whilst these appeared to influence efficacy, variations in the intervention and outcome assessment methods hindered the ability to draw conclusions about optimal parameters. Lower limb PAS research requires further investigation before considering its translation into clinical practice. Eight key recommendations serve as guide for enhancing future research in the field.
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Affiliation(s)
- Gemma Alder
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Nada Signal
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Sharon Olsen
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Denise Taylor
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
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16
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Abraha B, Chaves AR, Kelly LP, Wallack EM, Wadden KP, McCarthy J, Ploughman M. A Bout of High Intensity Interval Training Lengthened Nerve Conduction Latency to the Non-exercised Affected Limb in Chronic Stroke. Front Physiol 2018; 9:827. [PMID: 30013489 PMCID: PMC6036480 DOI: 10.3389/fphys.2018.00827] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/12/2018] [Indexed: 12/13/2022] Open
Abstract
Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke. Design: Randomized cross-over trial. Setting: Research laboratory in a tertiary rehabilitation hospital. Participants: Convenience sample of 12 chronic stroke survivors. Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength). Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R2 = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R2 = 0.26 p = 0.02). Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.
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Affiliation(s)
- Beraki Abraha
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Arthur R Chaves
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Liam P Kelly
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Elizabeth M Wallack
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Katie P Wadden
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Jason McCarthy
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Lab, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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17
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Federico P, Perez MA. Distinct Corticocortical Contributions to Human Precision and Power Grip. Cereb Cortex 2018; 27:5070-5082. [PMID: 27707769 DOI: 10.1093/cercor/bhw291] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/22/2016] [Indexed: 12/21/2022] Open
Abstract
The corticospinal tract contributes to the control of finger muscles during precision and power grip. The involvement of different sets of cortical interneuronal circuits during these distinct grasping behaviors remains unknown. To examine this question in humans we used noninvasive transcranial magnetic stimulation (TMS) over the hand representation of the primary motor cortex to elicit motor evoked potentials (MEPs) in an intrinsic finger muscle during index finger abduction (control task), precision grip, and power grip. The TMS coil was oriented to induce currents in the brain in the latero-medial (LM), posterior-anterior (PA), and anterior-posterior (AP) direction to preferentially activate corticospinal axons directly and early and late synaptic inputs to corticospinal neurons, respectively. We found that AP-LM MEP latency differences were consistently longer during power grip compared with index finger abduction and precision grip, while PA-LM differences remained similar across tasks. Short-interval intracortical facilitation, targeting AP but not PA inputs, increased during power grip compared with other tasks. Our novel findings suggest that cortical structures activated by PA and AP stimuli are differentially active during precision and power grip. We propose that a preferential recruitment of late synaptic inputs to corticospinal neurons may be achieved when humans perform a power grip.
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Affiliation(s)
- Paolo Federico
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, FL33136, USA
| | - Monica A Perez
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, FL33136, USA
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18
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Mooney RA, Cirillo J, Byblow WD. Adaptive threshold hunting for the effects of transcranial direct current stimulation on primary motor cortex inhibition. Exp Brain Res 2018; 236:1651-1663. [DOI: 10.1007/s00221-018-5250-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 03/30/2018] [Indexed: 11/25/2022]
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19
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Huang YZ, Lu MK, Antal A, Classen J, Nitsche M, Ziemann U, Ridding M, Hamada M, Ugawa Y, Jaberzadeh S, Suppa A, Paulus W, Rothwell J. Plasticity induced by non-invasive transcranial brain stimulation: A position paper. Clin Neurophysiol 2017; 128:2318-2329. [DOI: 10.1016/j.clinph.2017.09.007] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 08/31/2017] [Accepted: 09/05/2017] [Indexed: 12/11/2022]
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20
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Polarity-independent effects of tDCS on paired associative stimulation-induced plasticity. Brain Stimul 2017; 10:1061-1069. [DOI: 10.1016/j.brs.2017.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/24/2017] [Accepted: 07/25/2017] [Indexed: 12/19/2022] Open
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21
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Abstract
PURPOSE OF REVIEW To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain stimulation. Trait-related and state-related determinants contribute to this variability, challenging the standard approach to apply stimulation in a rigid, one-size-fits-all fashion. Several strategies have been identified to reduce variability and maximize the plasticity-inducing effects of noninvasive transcranial brain stimulation. Priming interventions or paired associative stimulation can be used to 'standardize' the brain-state and hereby, homogenize the group response to stimulation. Neuroanatomical and neurochemical profiling based on magnetic resonance imaging and spectroscopy can capture trait-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified rules. In contrast, adaptive closed-loop stimulation dynamically adjusts stimulation settings based on the occurrence of stimulation-induced state changes. SUMMARY Approaches that take into account trait-related and state-related determinants of stimulation-induced plasticity bear considerable potential to establish noninvasive transcranial brain stimulation as interventional therapeutic tool.
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22
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Nuzum ND, Hendy AM, Russell AP, Teo WP. Measures to Predict The Individual Variability of Corticospinal Responses Following Transcranial Direct Current Stimulation. Front Hum Neurosci 2016; 10:487. [PMID: 27766075 PMCID: PMC5052268 DOI: 10.3389/fnhum.2016.00487] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 09/14/2016] [Indexed: 12/20/2022] Open
Abstract
Individual responses to transcranial direct current stimulation (tDCS) are varied and therefore potentially limit its application. There is evidence that this variability is related to the contributions of Indirect waves (I-waves) recruited in the cortex. The latency of motor-evoked potentials (MEPs) can be measured through transcranial magnetic stimulation (TMS), allowing an individual's responsiveness to tDCS to be determined. However, this single-pulse method requires several different orientations of the TMS coil, potentially affecting its reliability. Instead, we propose a paired-pulse TMS paradigm targeting I-waves as an alternative method. This method uses one orientation that reduces inter- and intra-trial variability. It was hypothesized that the paired-pulse method would correlate more highly to tDCS responses than the single-pulse method. In a randomized, double blinded, cross-over design, 30 healthy participants completed two sessions, receiving 20 min of either anodal (2 mA) or sham tDCS. TMS was used to quantify Short interval intracortical facilitation (SICF) at Inter stimulus intervals (ISIs) of 1.5, 3.5 and 4.5 ms. Latency was determined in the posterior-anterior (PA), anterior-posterior (AP) and latero-medial (LM) coil orientations. The relationship between latency, SICF measures and the change in suprathreshold MEP amplitude size following tDCS were determined with Pearson's correlations. TMS measures, SICI and SICF were also used to determine responses to Anodal-tDCS (a-tDCS). Neither of the latency differences nor the SICF measures correlated to the change in MEP amplitude from pre-post tDCS (all P > 0.05). Overall, there was no significant response to tDCS in this cohort. This study highlights the need for testing the effects of various tDCS protocols on the different I-waves. Further research into SICF and whether it is a viable measure of I-wave facilitation is warranted.
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Affiliation(s)
- Nathan D Nuzum
- School of Exercise and Nutrition Sciences, Deakin University Geelong, VIC, Australia
| | - Ashlee M Hendy
- School of Exercise and Nutrition Sciences, Deakin University Geelong, VIC, Australia
| | - Aaron P Russell
- Institute for Physical Activity and Nutrition (IPAN), Deakin University Geelong, VIC, Australia
| | - Wei-Peng Teo
- Institute for Physical Activity and Nutrition (IPAN), Deakin University Geelong, VIC, Australia
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23
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Facilitatory non-invasive brain stimulation in older adults: the effect of stimulation type and duration on the induction of motor cortex plasticity. Exp Brain Res 2016; 234:3411-3423. [DOI: 10.1007/s00221-016-4740-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/19/2016] [Indexed: 10/21/2022]
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24
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Tremblay S, Larochelle-Brunet F, Lafleur LP, El Mouderrib S, Lepage JF, Théoret H. Systematic assessment of duration and intensity of anodal transcranial direct current stimulation on primary motor cortex excitability. Eur J Neurosci 2016; 44:2184-90. [DOI: 10.1111/ejn.13321] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/14/2016] [Accepted: 06/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Sara Tremblay
- Département de Psychologie; Université de Montréal; Montréal QC Canada
- Sobell Department of Motor Neuroscience and Movement Disorders; Institute of Neurology; University College London; 33 Queen Square London WC1N 3BG UK
| | | | | | | | - Jean-François Lepage
- Centre de Recherche du CHU Sherbrooke; Sherbrooke QC Canada
- Département de Pédiatrie; Université de Sherbrooke; Sherbrooke QC Canada
- Université du Québec à Trois-Rivières; Trois-Rivières QC Canada
| | - Hugo Théoret
- Département de Psychologie; Université de Montréal; Montréal QC Canada
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25
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Royter V, Gharabaghi A. Brain State-Dependent Closed-Loop Modulation of Paired Associative Stimulation Controlled by Sensorimotor Desynchronization. Front Cell Neurosci 2016; 10:115. [PMID: 27242429 PMCID: PMC4861730 DOI: 10.3389/fncel.2016.00115] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 04/20/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Pairing peripheral electrical stimulation (ES) and transcranial magnetic stimulation (TMS) increases corticospinal excitability when applied with a specific temporal pattern. When the two stimulation techniques are applied separately, motor imagery (MI)-related oscillatory modulation amplifies both ES-related cortical effects-sensorimotor event-related desynchronization (ERD), and TMS-induced peripheral responses-motor-evoked potentials (MEP). However, the influence of brain self-regulation on the associative pairing of these stimulation techniques is still unclear. OBJECTIVE The aim of this pilot study was to investigate the effects of MI-related ERD during associative ES and TMS on subsequent corticospinal excitability. METHOD The paired application of functional electrical stimulation (FES) of the extensor digitorum communis (EDC) muscle and subsequent single-pulse TMS (110% resting motor threshold (RMT)) of the contralateral primary motor cortex (M1) was controlled by beta-band (16-22 Hz) ERD during MI of finger extension and applied within a brain-machine interface environment in six healthy subjects. Neural correlates were probed by acquiring the stimulus-response curve (SRC) of both MEP peak-to-peak amplitude and area under the curve (AUC) before and after the intervention. RESULT The application of approximately 150 pairs of associative FES and TMS resulted in a significant increase of MEP amplitudes and AUC, indicating that the induced increase of corticospinal excitability was mediated by the recruitment of additional neuronal pools. MEP increases were brain state-dependent and correlated with beta-band ERD, but not with the background EDC muscle activity; this finding was independent of the FES intensity applied. CONCLUSION These results could be relevant for developing closed-loop therapeutic approaches such as the application of brain state-dependent, paired associative stimulation (PAS) in the context of neurorehabilitation.
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Affiliation(s)
- Vladislav Royter
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
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26
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McCambridge AB, Stinear JW, Byblow WD. Neurophysiological and behavioural effects of dual-hemisphere transcranial direct current stimulation on the proximal upper limb. Exp Brain Res 2016; 234:1419-28. [PMID: 26749182 DOI: 10.1007/s00221-015-4547-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/23/2015] [Indexed: 11/25/2022]
Abstract
Dual-hemisphere transcranial direct current stimulation over the primary motor cortex (M1-M1 tDCS) is assumed to modulate neural excitability in a polarity-dependent manner and improve motor performance of the hand. In the proximal upper limb, the neurophysiological and behavioural after-effects of M1-M1 tDCS are not well known. This study investigated the after-effects of M1-M1 tDCS on contralateral, ipsilateral and transcallosal excitability to the proximal upper limb muscle biceps brachii (BB). Circle tracing was used to assess motor performance before and after tDCS as this task requires coordination of proximal and distal musculature. Sixteen healthy right-handed adults participated in the study, each receiving M1-M1 tDCS (1 mA, 15 min) or sham tDCS in separate sessions. The anode was positioned over right M1 and cathode over left M1. M1-M1 tDCS suppressed transcallosal inhibition from the M1 under the cathode (P < 0.045). No other neurophysiologic or behavioural effects were observed (P > 0.6). The study provides important information regarding inconsistent neurophysiological and behavioural changes following tDCS that have implications for future tDCS research on the motor system.
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Affiliation(s)
- Alana B McCambridge
- Movement Neuroscience Laboratory, Department of Exercise Sciences, and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - James W Stinear
- Movement Neuroscience Laboratory, Department of Exercise Sciences, and Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Winston D Byblow
- Movement Neuroscience Laboratory, Department of Exercise Sciences, and Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
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