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Sasaki R, Hand BJ, Liao WY, Semmler JG, Opie GM. Investigating the Effects of Repetitive Paired-Pulse Transcranial Magnetic Stimulation on Visuomotor Training Using TMS-EEG. Brain Topogr 2024:10.1007/s10548-024-01071-1. [PMID: 39066878 DOI: 10.1007/s10548-024-01071-1] [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: 02/28/2024] [Accepted: 07/21/2024] [Indexed: 07/30/2024]
Abstract
I-wave periodicity repetitive paired-pulse transcranial magnetic stimulation (iTMS) can modify acquisition of a novel motor skill, but the associated neurophysiological effects remain unclear. The current study therefore used combined TMS-electroencephalography (TMS-EEG) to investigate the neurophysiological effects of iTMS on subsequent visuomotor training (VT). Sixteen young adults (26.1 ± 5.1 years) participated in three sessions including real iTMS and VT (iTMS + VT), control iTMS and VT (iTMSControl + VT), or iTMS alone. Motor-evoked potentials (MEPs) and TMS-evoked potentials (TEPs) were measured before and after iTMS, and again after VT, to assess neuroplastic changes. Irrespective of the intervention, MEP amplitude was not changed after iTMS or VT. Motor skill was improved compared with baseline, but no differences were found between stimulus conditions. In contrast, the P30 peak was altered by VT when preceded by control iTMS (P < 0.05), but this effect was not apparent when VT was preceded by iTMS or following iTMS alone (all P > 0.15). In contrast to expectations, iTMS was unable to modulate MEP amplitude or influence motor learning. Despite this, changes in P30 amplitude suggested that motor learning was associated with altered cortical reactivity. Furthermore, this effect was abolished by priming with iTMS, suggesting an influence of priming that failed to impact learning.
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Affiliation(s)
- Ryoki Sasaki
- Discipline of Physiology, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Brodie J Hand
- Discipline of Physiology, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Wei-Yeh Liao
- Discipline of Physiology, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - John G Semmler
- Discipline of Physiology, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - George M Opie
- Discipline of Physiology, The University of Adelaide, Adelaide, SA, 5005, Australia.
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2
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Debenham MIB, Franz CK, Berger MJ. Neuromuscular consequences of spinal cord injury: New mechanistic insights and clinical considerations. Muscle Nerve 2024; 70:12-27. [PMID: 38477416 DOI: 10.1002/mus.28070] [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: 10/20/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024]
Abstract
The spinal cord facilitates communication between the brain and the body, containing intrinsic systems that work with lower motor neurons (LMNs) to manage movement. Spinal cord injuries (SCIs) can lead to partial paralysis and dysfunctions in muscles below the injury. While traditionally this paralysis has been attributed to disruptions in the corticospinal tract, a growing body of work demonstrates LMN damage is a factor. Motor units, comprising the LMN and the muscle fibers with which they connect, are essential for voluntary movement. Our understanding of their changes post-SCI is still emerging, but the health of motor units is vital, especially when considering innovative SCI treatments like nerve transfer surgery. This review seeks to collate current literature on how SCI impact motor units and explore neuromuscular clinical implications and treatment avenues. SCI reduced motor unit number estimates, and surviving motor units had impaired signal transmission at the neuromuscular junction, force-generating capacity, and excitability, which have the potential to recover chronically, yet the underlaying mechanisms are unclear. Furthermore, electrodiagnostic evaluations can aid in assessing the health lower and upper motor neurons, identify suitable targets for nerve transfer surgeries, and detect patients with time sensitive injuries. Lastly, many electrodiagnostic abnormalities occur in both chronic and acute SCI, yet factors contributing to these abnormalities are unknown. Future studies are required to determine how motor units adapt following SCI and the clinical implications of these adaptations.
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Affiliation(s)
- Mathew I B Debenham
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin K Franz
- Biologics Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Tian Y, Tan C, Tan J, Yang L, Tang Y. Top-down modulation of DLPFC in visual search: a study based on fMRI and TMS. Cereb Cortex 2024; 34:bhad540. [PMID: 38212289 DOI: 10.1093/cercor/bhad540] [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: 11/06/2023] [Revised: 12/23/2023] [Accepted: 12/24/2023] [Indexed: 01/13/2024] Open
Abstract
Effective visual search is essential for daily life, and attention orientation as well as inhibition of return play a significant role in visual search. Researches have established the involvement of dorsolateral prefrontal cortex in cognitive control during selective attention. However, neural evidence regarding dorsolateral prefrontal cortex modulates inhibition of return in visual search is still insufficient. In this study, we employed event-related functional magnetic resonance imaging and dynamic causal modeling to develop modulation models for two types of visual search tasks. In the region of interest analyses, we found that the right dorsolateral prefrontal cortex and temporoparietal junction were selectively activated in the main effect of search type. Dynamic causal modeling results indicated that temporoparietal junction received sensory inputs and only dorsolateral prefrontal cortex →temporoparietal junction connection was modulated in serial search. Such neural modulation presents a significant positive correlation with behavioral reaction time. Furthermore, theta burst stimulation via transcranial magnetic stimulation was utilized to modulate the dorsolateral prefrontal cortex region, resulting in the disappearance of the inhibition of return effect during serial search after receiving continuous theta burst stimulation. Our findings provide a new line of causal evidence that the top-down modulation by dorsolateral prefrontal cortex influences the inhibition of return effect during serial search possibly through the retention of inhibitory tagging via working memory storage.
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Affiliation(s)
- Yin Tian
- School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
- School of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
- Institute for Advanced Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
- Chongqing Institute for Brain and Intelligence, Guangyang Bay Laboratory, Chongqing 400064, China
| | - Congming Tan
- School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Jianling Tan
- School of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Li Yang
- School of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
- Department of Medical Engineering, Daping Hospital, Army Medical University, ChongQing 400065, China
| | - Yi Tang
- School of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
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van Helden JFL, Alexander E, Cabral HV, Strutton PH, Martinez-Valdes E, Falla D, Chowdhury JR, Chiou SY. Home-based arm cycling exercise improves trunk control in persons with incomplete spinal cord injury: an observational study. Sci Rep 2023; 13:22120. [PMID: 38092831 PMCID: PMC10719287 DOI: 10.1038/s41598-023-49053-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/04/2023] [Indexed: 12/17/2023] Open
Abstract
Arm cycling is used for cardiorespiratory rehabilitation but its therapeutic effects on the neural control of the trunk after spinal cord injury (SCI) remain unclear. We investigated the effects of single session of arm cycling on corticospinal excitability, and the feasibility of home-based arm cycling exercise training on volitional control of the erector spinae (ES) in individuals with incomplete SCI. Using transcranial magnetic stimulation, we assessed motor evoked potentials (MEPs) in the ES before and after 30 min of arm cycling in 15 individuals with SCI and 15 able-bodied controls (Experiment 1). Both groups showed increased ES MEP size after the arm cycling. The participants with SCI subsequently underwent a 6-week home-based arm cycling exercise training (Experiment 2). MEP amplitudes and activity of the ES, and movements of the trunk during reaching, self-initiated rapid shoulder flexion, and predicted external perturbation tasks were measured. After the training, individuals with SCI reached further and improved trajectory of the trunk during the rapid shoulder flexion task, accompanied by increased ES activity and MEP amplitudes. Exercise adherence was excellent. We demonstrate preserved corticospinal drive after a single arm cycling session and the effects of home-based arm cycling exercise training on trunk function in individuals with SCI.
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Affiliation(s)
- Joeri F L van Helden
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Emma Alexander
- The Royal London Hospital, Barts Health NHS Trust, London, UK
| | - Hélio V Cabral
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Paul H Strutton
- Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, London, UK
| | - Eduardo Martinez-Valdes
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Joy Roy Chowdhury
- Midland Centre for Spinal Injuries, The Robert Jones and Agnes Hunt Orthopaedic Hospital NHSFT, Oswestry, UK
| | - Shin-Yi Chiou
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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Colamarino E, Lorusso M, Pichiorri F, Toppi J, Tamburella F, Serratore G, Riccio A, Tomaiuolo F, Bigioni A, Giove F, Scivoletto G, Cincotti F, Mattia D. DiSCIoser: unlocking recovery potential of arm sensorimotor functions after spinal cord injury by promoting activity-dependent brain plasticity by means of brain-computer interface technology: a randomized controlled trial to test efficacy. BMC Neurol 2023; 23:414. [PMID: 37990160 PMCID: PMC10662594 DOI: 10.1186/s12883-023-03442-w] [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] [Received: 10/12/2023] [Accepted: 10/19/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND Traumatic cervical spinal cord injury (SCI) results in reduced sensorimotor abilities that strongly impact on the achievement of daily living activities involving hand/arm function. Among several technology-based rehabilitative approaches, Brain-Computer Interfaces (BCIs) which enable the modulation of electroencephalographic sensorimotor rhythms, are promising tools to promote the recovery of hand function after SCI. The "DiSCIoser" study proposes a BCI-supported motor imagery (MI) training to engage the sensorimotor system and thus facilitate the neuroplasticity to eventually optimize upper limb sensorimotor functional recovery in patients with SCI during the subacute phase, at the peak of brain and spinal plasticity. To this purpose, we have designed a BCI system fully compatible with a clinical setting whose efficacy in improving hand sensorimotor function outcomes in patients with traumatic cervical SCI will be assessed and compared to the hand MI training not supported by BCI. METHODS This randomized controlled trial will include 30 participants with traumatic cervical SCI in the subacute phase randomly assigned to 2 intervention groups: the BCI-assisted hand MI training and the hand MI training not supported by BCI. Both interventions are delivered (3 weekly sessions; 12 weeks) as add-on to standard rehabilitation care. A multidimensional assessment will be performed at: randomization/pre-intervention and post-intervention. Primary outcome measure is the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) somatosensory sub-score. Secondary outcome measures include the motor and functional scores of the GRASSP and other clinical, neuropsychological, neurophysiological and neuroimaging measures. DISCUSSION We expect the BCI-based intervention to promote meaningful cortical sensorimotor plasticity and eventually maximize recovery of arm functions in traumatic cervical subacute SCI. This study will generate a body of knowledge that is fundamental to drive optimization of BCI application in SCI as a top-down therapeutic intervention, thus beyond the canonical use of BCI as assistive tool. TRIAL REGISTRATION Name of registry: DiSCIoser: improving arm sensorimotor functions after spinal cord injury via brain-computer interface training (DiSCIoser). TRIAL REGISTRATION NUMBER NCT05637775; registration date on the ClinicalTrial.gov platform: 05-12-2022.
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Affiliation(s)
- Emma Colamarino
- Department of Computer, Control, and Management Engineering "Antonio Ruberti", Sapienza University of Rome, Via Ariosto, 25, 00185, Rome, Italy.
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy.
| | - Matteo Lorusso
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
| | | | - Jlenia Toppi
- Department of Computer, Control, and Management Engineering "Antonio Ruberti", Sapienza University of Rome, Via Ariosto, 25, 00185, Rome, Italy
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
| | | | - Giada Serratore
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
| | - Angela Riccio
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
| | - Francesco Tomaiuolo
- Department of Clinical and Experimental Medicine, University of Messina, Piazza Pugliatti, 1, 98122, Messina, Italy
| | | | - Federico Giove
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
- Museo Storico Della Fisica E Centro Studi E Ricerche Enrico Fermi, Via Panisperna, 89a, 00184, Rome, Italy
| | | | - Febo Cincotti
- Department of Computer, Control, and Management Engineering "Antonio Ruberti", Sapienza University of Rome, Via Ariosto, 25, 00185, Rome, Italy
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
| | - Donatella Mattia
- IRCCS Fondazione Santa Lucia, Via Ardeatina, 306, 00179, Rome, Italy
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Campos B, Choi H, DeMarco AT, Seydell-Greenwald A, Hussain SJ, Joy MT, Turkeltaub PE, Zeiger W. Rethinking Remapping: Circuit Mechanisms of Recovery after Stroke. J Neurosci 2023; 43:7489-7500. [PMID: 37940595 PMCID: PMC10634578 DOI: 10.1523/jneurosci.1425-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 11/10/2023] Open
Abstract
Stroke is one of the most common causes of disability, and there are few treatments that can improve recovery after stroke. Therapeutic development has been hindered because of a lack of understanding of precisely how neural circuits are affected by stroke, and how these circuits change to mediate recovery. Indeed, some of the hypotheses for how the CNS changes to mediate recovery, including remapping, redundancy, and diaschisis, date to more than a century ago. Recent technological advances have enabled the interrogation of neural circuits with ever greater temporal and spatial resolution. These techniques are increasingly being applied across animal models of stroke and to human stroke survivors, and are shedding light on the molecular, structural, and functional changes that neural circuits undergo after stroke. Here we review these studies and highlight important mechanisms that underlie impairment and recovery after stroke. We begin by summarizing knowledge about changes in neural activity that occur in the peri-infarct cortex, specifically considering evidence for the functional remapping hypothesis of recovery. Next, we describe the importance of neural population dynamics, disruptions in these dynamics after stroke, and how allocation of neurons into spared circuits can restore functionality. On a more global scale, we then discuss how effects on long-range pathways, including interhemispheric interactions and corticospinal tract transmission, contribute to post-stroke impairments. Finally, we look forward and consider how a deeper understanding of neural circuit mechanisms of recovery may lead to novel treatments to reduce disability and improve recovery after stroke.
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Affiliation(s)
- Baruc Campos
- Department of Neurology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
| | - Hoseok Choi
- Department of Neurology, Weill Institute for Neuroscience, University of California-San Francisco, San Francisco, California 94158
| | - Andrew T DeMarco
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- Department of Rehabilitation Medicine, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
| | - Anna Seydell-Greenwald
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- MedStar National Rehabilitation Hospital, Washington, DC 20010
| | - Sara J Hussain
- Movement and Cognitive Rehabilitation Science Program, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas 78712
| | - Mary T Joy
- The Jackson Laboratory, Bar Harbor, Maine 04609
| | - Peter E Turkeltaub
- Center for Brain Plasticity and Recovery, Georgetown University Medical Center, Georgetown University, Washington, DC 20057
- MedStar National Rehabilitation Hospital, Washington, DC 20010
| | - William Zeiger
- Department of Neurology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
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Hand BJ, Merkin A, Opie GM, Ziemann U, Semmler JG. Repetitive paired-pulse TMS increases motor cortex excitability and visuomotor skill acquisition in young and older adults. Cereb Cortex 2023; 33:10660-10675. [PMID: 37689833 PMCID: PMC10560576 DOI: 10.1093/cercor/bhad315] [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: 05/23/2023] [Revised: 08/13/2023] [Accepted: 08/15/2023] [Indexed: 09/11/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) over primary motor cortex (M1) recruits indirect (I) waves that can be modulated by repetitive paired-pulse TMS (rppTMS). The purpose of this study was to examine the effect of rppTMS on M1 excitability and visuomotor skill acquisition in young and older adults. A total of 37 healthy adults (22 young, 18-32 yr; 15 older, 60-79 yr) participated in a study that involved rppTMS at early (1.4 ms) and late (4.5 ms) interstimulus intervals (ISIs), followed by the performance of a visuomotor training task. M1 excitability was examined with motor-evoked potential (MEP) amplitudes and short-interval intracortical facilitation (SICF) using posterior-anterior (PA) and anterior-posterior (AP) TMS current directions. We found that rppTMS increased M1 excitability in young and old adults, with the greatest effects for PA TMS at the late ISI (4.5 ms). Motor skill acquisition was improved by rppTMS at an early (1.4 ms) but not late (4.5 ms) ISI in young and older adults. An additional study using a non-I-wave interval (3.5 ms) also showed increased M1 excitability and visuomotor skill acquisition. These findings show that rppTMS at both I-wave and non-I-wave intervals can alter M1 excitability and improve visuomotor skill acquisition in young and older adults.
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Affiliation(s)
- Brodie J Hand
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide 5005, Australia
| | - Ashley Merkin
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide 5005, Australia
| | - George M Opie
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide 5005, Australia
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen 72076, Germany
| | - John G Semmler
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide 5005, Australia
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Sasaki R, Liao W, Opie GM, Semmler JG. Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired-pulse transcranial magnetic stimulation. Eur J Neurosci 2023; 58:3270-3285. [PMID: 37501330 PMCID: PMC10946698 DOI: 10.1111/ejn.16099] [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: 01/19/2023] [Accepted: 07/06/2023] [Indexed: 07/29/2023]
Abstract
Repetitive paired-pulse transcranial magnetic stimulation (TMS) at indirect (I)-wave periodicity (iTMS) can increase plasticity in primary motor cortex (M1). Both TMS coil orientation and muscle activation can influence I-wave activity, but it remains unclear how these factors influence M1 plasticity with iTMS. We therefore investigated the influence of TMS coil orientation and muscle activation on the response to iTMS. Thirty-two young adults (24.2 ± 4.8 years) participated in three experiments. Each experiment included two sessions using a modified iTMS intervention with either a posterior-anterior orientation (PA) or anterior-posterior (AP) coil orientation over M1. Stimulation was applied in resting (Experiments 1 and 3) or active muscle (Experiments 2 and 3). Effects of iTMS on M1 excitability were assessed by recording motor evoked potentials (MEPs) and short-interval intracortical facilitation (SICF) with PA and AP orientations in both resting (all experiments) and active (Experiment 2) muscle. For the resting intervention, MEPs were greater after AP iTMS (Experiment 1, P = .046), whereas SICF was comparable between interventions (all P > .10). For the active intervention, responses did not vary between PA and AP iTMS (Experiment 2, all P > .14), and muscle activation reduced the effect of AP iTMS during the intervention (Experiment 3, P = .002). Coil orientation influenced the MEP response after iTMS, and muscle activation reduced the response during iTMS. While this suggests that AP iTMS may be beneficial in producing a neuroplastic modulation of I-wave circuits in resting muscle, further exploration of factors such as dosing is required.
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Affiliation(s)
- Ryoki Sasaki
- Discipline of PhysiologyUniversity of AdelaideAdelaideAustralia
| | - Wei‐Yeh Liao
- Discipline of PhysiologyUniversity of AdelaideAdelaideAustralia
| | - George M. Opie
- Discipline of PhysiologyUniversity of AdelaideAdelaideAustralia
| | - John G. Semmler
- Discipline of PhysiologyUniversity of AdelaideAdelaideAustralia
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Dai CQ, Gao M, Lin XD, Xue BJ, Liang Y, Xu ML, Wu XB, Cheng GQ, Hu X, Zhao CG, Yuan H, Sun XL. Primary motor hand area corticospinal excitability indicates overall functional recovery after spinal cord injury. Front Neurol 2023; 14:1175078. [PMID: 37333013 PMCID: PMC10273270 DOI: 10.3389/fneur.2023.1175078] [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: 02/27/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Background After spinal cord injury (SCI), the excitability of the primary motor cortex (M1) lower extremity area decreases or disappears. A recent study reported that the M1 hand area of the SCI patient encodes the activity information of both the upper and lower extremities. However, the characteristics of the M1 hand area corticospinal excitability (CSE) changes after SCI and its correlation with extremities motor function are still unknown. Methods A retrospective study was conducted on the data of 347 SCI patients and 80 healthy controls on motor evoked potentials (MEP, reflection of CSE), extremity motor function, and activities of daily living (ADL) ability. Correlation analysis and multiple linear regression analysis were conducted to analyze the relationship between the degree of MEP hemispheric conversion and extremity motor function/ADL ability. Results The CSE of the dominant hemisphere M1 hand area decreased in SCI patients. In 0-6 m, AIS A grade, or non-cervical injury SCI patients, the degree of M1 hand area MEP hemispheric conversion was positively correlated with total motor score, lower extremity motor score (LEMS), and ADL ability. Multiple linear regression analysis further confirmed the contribution of MEP hemispheric conversion degree in ADL changes as an independent factor. Conclusion The closer the degree of M1 hand area MEP hemispheric conversion is to that of healthy controls, the better the extremity motor function/ADL ability patients achieve. Based on the law of this phenomenon, targeted intervention to regulate the excitability of bilateral M1 hand areas might be a novel strategy for SCI overall functional recovery.
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Affiliation(s)
- Chun-Qiu Dai
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
- Lintong Rehabilitation and Convalescent Centre, Xi'an, China
| | - Ming Gao
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Xiao-Dong Lin
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Bai-Jie Xue
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Ying Liang
- Department of Health Statistics, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Mu-Lan Xu
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Xiang-Bo Wu
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Gui-Qing Cheng
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Xu Hu
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Chen-Guang Zhao
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Hua Yuan
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
| | - Xiao-Long Sun
- Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi’an, China
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10
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Yang L, Martin JH. Effects of motor cortex neuromodulation on the specificity of corticospinal tract spinal axon outgrowth and targeting in rats. Brain Stimul 2023; 16:759-771. [PMID: 37094762 PMCID: PMC10501380 DOI: 10.1016/j.brs.2023.04.014] [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: 12/18/2022] [Revised: 04/01/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Neural activity helps construct neural circuits during development and this function is leveraged by neuromodulation protocols to promote connectivity and repair in maturity. Neuromodulation targeting the motor cortex (MCX) strengthens connections for evoking muscle contraction (MEPs). Mechanisms include promoting local MCX and corticospinal tract (CST) synaptic efficacy and also axon terminal structural changes. OBJECTIVE In this study, we address the question of potential causality between neuronal activation and the neuronal structural response. METHODS We used patterned optogenetic activation (ChR2-EYFP), daily for 10-days, to deliver intermittent theta burst stimulation (iTBS) to activate MCX neurons within the forelimb representation in healthy rats, while differentiating them from neurons in the same population that were not activated. We used chemogenetic DREADD activation to produce a daily period of non-patterned neuronal activation. RESULTS We found a significant increase in CST axon length, axon branching, contacts targeted to a class of premotor interneuron (Chx10), as well as projections into the motor pools in the ventral horn in optically activated but not neighboring non-activated neurons. A period of 2-h of continuous activation daily for 10 days using DREADD chemogenetic activation with systemic clozapine N-oxide (CNO) administration also increased CST axon length and branching, but not the ventral horn and Chx10 targeting effects. Both patterned optical and chemogenetic activation reduced MCX MEP thresholds. CONCLUSION Our findings show that targeting of CST axon sprouting is dependent on patterned activation, but that CST spinal axon outgrowth and branching are not. Our optogenetic findings, by distinguishing optically activated and non-activated CST axons, suggests that the switch for activity-dependent axonal outgrowth is neuron-intrinsic.
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Affiliation(s)
- Lillian Yang
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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Chen JM, Li XL, Pan QH, Yang Y, Xu SM, Xu JW. Effects of non-invasive brain stimulation on motor function after spinal cord injury: a systematic review and meta-analysis. J Neuroeng Rehabil 2023; 20:3. [PMID: 36635693 PMCID: PMC9837916 DOI: 10.1186/s12984-023-01129-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/07/2023] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND In recent years, non-invasive brain stimulation (NIBS) has been used for motor function recovery. However, the effects of NIBS in populations with spinal cord injury (SCI) remain unclear. This study aims to conduct a meta-analysis of the existing evidence on the effects and safety of NIBS against sham groups for motor dysfunction after SCI to provide a reference for clinical decision-making. METHODS Two investigators systematically screened English articles from PubMed, MEDLINE, Embase, and Cochrane Library for prospective randomized controlled trials regarding the effects of NIBS in motor function recovery after SCI. Studies with at least three sessions of NIBS were included. We assessed the methodological quality of the selected studies using the evidence-based Cochrane Collaboration's tool. A meta-analysis was performed by pooling the standardized mean difference (SMD) with 95% confidence intervals (CI). RESULTS A total of 14 randomized control trials involving 225 participants were included. Nine studies used repetitive transcranial magnetic stimulation (rTMS) and five studies used transcranial direct current stimulation (tDCS). The meta-analysis showed that NIBS could improve the lower extremity strength (SMD = 0.58, 95% CI = 0.02-1.14, P = 0.004), balance (SMD = 0.64, 95% CI = 0.05-1.24, P = 0.03), and decrease the spasticity (SMD = - 0.64, 95% CI = - 1.20 to - 0.03, P = 0.04). However, the motor ability of the upper extremity in the NIBS groups was not statistically significant compared with those in the control groups (upper-extremity strength: P = 0.97; function: P = 0.56; and spasticity: P = 0.12). The functional mobility in the NIBS groups did not reach statistical significance when compared with the sham NIBS groups (sham groups). Only one patient reported seizures that occurred during stimulation, and no other types of serious adverse events were reported. CONCLUSION NIBS appears to positively affect the motor function of the lower extremities in SCI patients, despite the marginal P-value and the high heterogeneity. Further high-quality clinical trials are needed to support or refute the use and optimize the stimulation parameters of NIBS in clinical practice.
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Affiliation(s)
- Jian-Min Chen
- grid.412594.f0000 0004 1757 2961Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China ,grid.412683.a0000 0004 1758 0400Department of Rehabilitation Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Xiao-Lu Li
- grid.412594.f0000 0004 1757 2961Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China
| | - Qin-He Pan
- grid.412594.f0000 0004 1757 2961Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China
| | - Ye Yang
- grid.412594.f0000 0004 1757 2961Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China
| | - Sen-Ming Xu
- grid.412594.f0000 0004 1757 2961Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China
| | - Jian-Wen Xu
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi Medical University, Guangxi, China.
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Guo Y, Zheng H, Long J. Gating at cortical level contributes to auditory-motor synchronization during repetitive finger tapping. Cereb Cortex 2022; 33:6198-6206. [PMID: 36563001 DOI: 10.1093/cercor/bhac495] [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: 10/17/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/24/2022] Open
Abstract
Sensory integration contributes to temporal coordination of the movement with external rhythms. How the information flowing of sensory inputs is regulated with increasing tapping rates and its function remains unknown. Here, somatosensory evoked potentials to ulnar nerve stimulation were recorded during auditory-cued repetitive right-index finger tapping at 0.5, 1, 2, 3, and 4 Hz in 13 healthy subjects. We found that sensory inputs were suppressed at subcortical level (represented by P14) and primary somatosensory cortex (S1, represented by N20/P25) during repetitive tapping. This suppression was decreased in S1 but not in subcortical level during fast repetitive tapping (2, 3, and 4 Hz) compared with slow repetitive tapping (0.5 and 1 Hz). Furthermore, we assessed the ability to analyze temporal information in S1 by measuring the somatosensory temporal discrimination threshold (STDT). STDT increased during fast repetitive tapping compared with slow repetitive tapping, which was negatively correlated with the task performance of phase shift and positively correlated with the peak-to-peak amplitude (% of resting) in S1 but not in subcortical level. These novel findings indicate that the increased sensory input (lower sensory gating) in S1 may lead to greater temporal uncertainty for sensorimotor integration dereasing the performance of repetitive movement during increasing tapping rates.
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Affiliation(s)
- Yaqiu Guo
- Jinan University, College of Information Science and Technology, Guangzhou 510632, China
| | - Huixian Zheng
- Jinan University, College of Information Science and Technology, Guangzhou 510632, China
| | - Jinyi Long
- Jinan University, College of Information Science and Technology, Guangzhou 510632, China
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Sasaki R, Hand BJ, Semmler JG, Opie GM. Modulation of I-Wave Generating Pathways With Repetitive Paired-Pulse Transcranial Magnetic Stimulation: A Transcranial Magnetic Stimulation–Electroencephalography Study. Neuromodulation 2022:S1094-7159(22)01353-8. [DOI: 10.1016/j.neurom.2022.10.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/11/2022] [Accepted: 10/30/2022] [Indexed: 12/03/2022]
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Amer A, Martin JH. Repeated motor cortex theta-burst stimulation produces persistent strengthening of corticospinal motor output and durable spinal cord structural changes in the rat. Brain Stimul 2022; 15:1013-1022. [PMID: 35850438 PMCID: PMC10164459 DOI: 10.1016/j.brs.2022.07.005] [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: 04/21/2022] [Revised: 06/29/2022] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The strength of connections between motor cortex (MCX) and muscle can be augmented with a variety of stimulation protocols. Augmenting MCX-to-muscle connection strength by neuromodulation may be a way to enhance the intact motor system's capacity for acquiring motor skills and promote function after injury to strengthen spared connections. But this enhancement must be maintained for functional improvements. OBJECTIVE We determined if brief MCX muscle evoked potential (MEP) enhancement produced by intermittent theta burst stimulation (iTBS) can be converted into a longer and structurally durable form of response enhancement with repeated daily and longer-term application. METHODS Electrical iTBS was delivered through an implanted MCX epidural electrode and MEPs were recorded using implanted EMG electrodes in awake naïve rats. MCX activity was modulated further using chemogenetic (DREADDs) excitation and inhibition. Corticospinal tract (CST) axons were traced and immunochemistry used to measure CST synapses. RESULTS A single MCX iTBS block (600 pulses) produced MEP LTP lasting ∼30-45 min. Concatenating five iTBS blocks within a 30-min session produced MEP LTP lasting 24-48 h, which could be strengthened or weakened by bidirectional MCX activity modulation. Effect duration was not changed. Finally, daily induction of this persistent MEP LTP with daily iTBS for 10-days produced MEP enhancement outlasting the stimulation period by at least 10 days, and accompanied by CST axonal outgrowth and structural changes at the CST-spinal interneuron synapse. CONCLUSION Our findings inform the mechanisms of iTBS and provide a framework for designing neuromodulatory strategies to promote durable enhancement of cortical motor actions.
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Affiliation(s)
- Alzahraa Amer
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA
| | - John H Martin
- Department of Molecular, Cellular, and Biomedical Sciences, Center for Discovery and Innovation, City University of New York School of Medicine, New York, NY, USA; Neuroscience Program, Graduate Center of the City University of New York, New York, NY, USA.
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Liao WY, Sasaki R, Semmler JG, Opie GM. Cerebellar transcranial direct current stimulation disrupts neuroplasticity of intracortical motor circuits. PLoS One 2022; 17:e0271311. [PMID: 35820111 PMCID: PMC9275832 DOI: 10.1371/journal.pone.0271311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/27/2022] [Indexed: 11/25/2022] Open
Abstract
While previous research using transcranial magnetic stimulation (TMS) suggest that cerebellum (CB) influences the neuroplastic response of primary motor cortex (M1), the role of different indirect (I) wave inputs in M1 mediating this interaction remains unclear. The aim of this study was therefore to assess how CB influences neuroplasticity of early and late I-wave circuits. 22 young adults (22 ± 2.7 years) participated in 3 sessions in which I-wave periodicity repetitive transcranial magnetic stimulation (iTMS) was applied over M1 during concurrent application of cathodal transcranial direct current stimulation over CB (tDCSCB). In each session, iTMS either targeted early I-waves (1.5 ms interval; iTMS1.5), late I-waves (4.5 ms interval; iTMS4.5), or had no effect (variable interval; iTMSSham). Changes due to the intervention were examined with motor evoked potential (MEP) amplitude using TMS protocols measuring corticospinal excitability (MEP1mV) and the strength of CB-M1 connections (CBI). In addition, we indexed I-wave activity using short-interval intracortical facilitation (SICF) and low-intensity single-pulse TMS applied with posterior-anterior (MEPPA) and anterior-posterior (MEPAP) current directions. Following both active iTMS sessions, there was no change in MEP1mV, CBI or SICF (all P > 0.05), suggesting that tDCSCB broadly disrupted the excitatory response that is normally seen following iTMS. However, although MEPAP also failed to facilitate after the intervention (P > 0.05), MEPPA potentiated following both active iTMS sessions (both P < 0.05). This differential response between current directions could indicate a selective effect of CB on AP-sensitive circuits.
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Affiliation(s)
- Wei-Yeh Liao
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide, Australia
| | - Ryoki Sasaki
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide, Australia
| | - John G. Semmler
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide, Australia
| | - George M. Opie
- Discipline of Physiology, School of Biomedicine, The University of Adelaide, Adelaide, Australia
- * E-mail:
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Benedetti B, Weidenhammer A, Reisinger M, Couillard-Despres S. Spinal Cord Injury and Loss of Cortical Inhibition. Int J Mol Sci 2022; 23:5622. [PMID: 35628434 PMCID: PMC9144195 DOI: 10.3390/ijms23105622] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
After spinal cord injury (SCI), the destruction of spinal parenchyma causes permanent deficits in motor functions, which correlates with the severity and location of the lesion. Despite being disconnected from their targets, most cortical motor neurons survive the acute phase of SCI, and these neurons can therefore be a resource for functional recovery, provided that they are properly reconnected and retuned to a physiological state. However, inappropriate re-integration of cortical neurons or aberrant activity of corticospinal networks may worsen the long-term outcomes of SCI. In this review, we revisit recent studies addressing the relation between cortical disinhibition and functional recovery after SCI. Evidence suggests that cortical disinhibition can be either beneficial or detrimental in a context-dependent manner. A careful examination of clinical data helps to resolve apparent paradoxes and explain the heterogeneity of treatment outcomes. Additionally, evidence gained from SCI animal models indicates probable mechanisms mediating cortical disinhibition. Understanding the mechanisms and dynamics of cortical disinhibition is a prerequisite to improve current interventions through targeted pharmacological and/or rehabilitative interventions following SCI.
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Affiliation(s)
- Bruno Benedetti
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Annika Weidenhammer
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Maximilian Reisinger
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
| | - Sebastien Couillard-Despres
- Institute of Experimental Neuroregeneration, Paracelsus Medical University, 5020 Salzburg, Austria; (B.B.); (A.W.); (M.R.)
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), 5020 Salzburg, Austria
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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17
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Differences in sensorimotor and functional recovery between the dominant and non-dominant upper extremity following cervical spinal cord injury. Spinal Cord 2022; 60:422-427. [PMID: 35273373 DOI: 10.1038/s41393-022-00782-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 02/18/2022] [Accepted: 02/20/2022] [Indexed: 11/08/2022]
Abstract
STUDY DESIGN Post hoc analysis of prospective multi-national, multi-centre cohort study. OBJECTIVE Determine whether cerebral dominance influences upper extremity recovery following cervical spinal cord injury (SCI). SETTING A multi-national subset of the longitudinal GRASSP dataset (n = 127). METHODS Secondary analysis of prospective, longitudinal multicenter study of individuals with cervical SCI (n = 73). Study participants were followed for up to 12 months after a cervical SCI, and the following outcome measures were serially assessed - the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) and the International Standards for the Neurological Classification of SCI (ISNCSCI), including upper extremity motor and sensory scores. Observed recovery and relative (percent) recovery were then determined for both the GRASSP and ISNCSCI, based on change from initial to last available assessment. RESULTS With the exception of prehension performance (quantitative grasping) following complete cervical SCI, there were no significant differences (p < 0.05) for observed and relative (percent) recovery, between the dominant and non-dominant upper extremities, as measured using GRASSP subtests, ISNCSCI motor scores and ISNCSCI sensory scores. CONCLUSION Despite well documented differences between the cerebral hemispheres, cerebral dominance appears to play a limited role in upper extremity recovery following acute cervical SCI.
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18
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Mao YR, Jin ZX, Zheng Y, Fan J, Zhao LJ, Xu W, Hu X, Gu CY, Lu WW, Zhu GY, Chen YH, Cheng LM, Xu DS. Effects of cortical intermittent theta burst stimulation combined with precise root stimulation on motor function after spinal cord injury: a case series study. Neural Regen Res 2022; 17:1821-1826. [PMID: 35017444 PMCID: PMC8820710 DOI: 10.4103/1673-5374.332158] [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] [Indexed: 11/04/2022] Open
Abstract
Activation and reconstruction of the spinal cord circuitry is important for improving motor function following spinal cord injury. We conducted a case series study to investigate motor function improvement in 14 patients with chronic spinal cord injury treated with 4 weeks of unilateral (right only) cortical intermittent theta burst stimulation combined with bilateral magnetic stimulation of L3-L4 nerve roots, five times a week. Bilateral resting motor evoked potential amplitude was increased, central motor conduction time on the side receiving cortical stimulation was significantly decreased, and lower extremity motor score, Berg balance score, spinal cord independence measure-III score, and 10 m-walking speed were all increased after treatment. Right resting motor evoked potential amplitude was positively correlated with lower extremity motor score after 4 weeks of treatment. These findings suggest that cortical intermittent theta burst stimulation combined with precise root stimulation can improve nerve conduction of the corticospinal tract and lower limb motor function recovery in patients with chronic spinal cord injury.
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Affiliation(s)
- Ye-Ran Mao
- Department of Rehabilitation, Baoshan Branch, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine; Institute of Rehabilitation Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhong-Xia Jin
- Department of Spinal Cord Injury Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital, Shanghai Sunshine Rehabilitation Center, Tongji University School of Medicine, Shanghai, China
| | - Ya Zheng
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Jian Fan
- Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Li-Juan Zhao
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Wei Xu
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Xiao Hu
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Chun-Ya Gu
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Wei-Wei Lu
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Guang-Yue Zhu
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Yu-Hui Chen
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Li-Ming Cheng
- Spine Surgery Division of Department of Orthopedics, Tongji Hospital Affiliated to Tongji University School of Medicine; Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Shanghai, China
| | - Dong-Sheng Xu
- Institute of Rehabilitation Medicine, Shanghai University of Traditional Chinese Medicine; Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, China
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Preconditioning with Cathodal High-Definition Transcranial Direct Current Stimulation Sensitizes the Primary Motor Cortex to Subsequent Intermittent Theta Burst Stimulation. Neural Plast 2021; 2021:8966584. [PMID: 34721571 PMCID: PMC8553444 DOI: 10.1155/2021/8966584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/23/2021] [Accepted: 09/18/2021] [Indexed: 11/17/2022] Open
Abstract
Noninvasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) can induce long-term potentiation-like facilitation, but whether the combination of TMS and tDCS has additive effects is unclear. To address this issue, in this randomized crossover study, we investigated the effect of preconditioning with cathodal high-definition (HD) tDCS on intermittent theta burst stimulation- (iTBS-) induced plasticity in the left motor cortex. A total of 24 healthy volunteers received preconditioning with cathodal HD-tDCS or sham intervention prior to iTBS in a random order with a washout period of 1 week. The amplitude of motor evoked potentials (MEPs) was measured at baseline and at several time points (5, 10, 15, and 30 min) after iTBS to determine the effects of the intervention on cortical plasticity. Preconditioning with cathodal HD-tDCS followed by iTBS showed a greater increase in MEP amplitude than sham cathodal HD-tDCS preconditioning and iTBS at each time postintervention point, with longer-lasting after-effects on cortical excitability. These results demonstrate that preintervention with cathodal HD-tDCS primes the motor cortex for long-term potentiation induced by iTBS and is a potential strategy for improving the clinical outcome to guide therapeutic decisions.
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20
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Global Transcriptional Analyses of the Wnt-Induced Development of Neural Stem Cells from Human Pluripotent Stem Cells. Int J Mol Sci 2021; 22:ijms22147473. [PMID: 34299091 PMCID: PMC8308016 DOI: 10.3390/ijms22147473] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 12/28/2022] Open
Abstract
The differentiation of human pluripotent stem cells (hPSCs) to neural stem cells (NSCs) is the key initial event in neurogenesis and is thought to be dependent on the family of Wnt growth factors, their receptors and signaling proteins. The delineation of the transcriptional pathways that mediate Wnt-induced hPSCs to NSCs differentiation is vital for understanding the global genomic mechanisms of the development of NSCs and, potentially, the creation of new protocols in regenerative medicine. To understand the genomic mechanism of Wnt signaling during NSCs development, we treated hPSCs with Wnt activator (CHIR-99021) and leukemia inhibitory factor (LIF) in a chemically defined medium (N2B27) to induce NSCs, referred to as CLNSCs. The CLNSCs were subcultured for more than 40 passages in vitro; were positive for AP staining; expressed neural progenitor markers such as NESTIN, PAX6, SOX2, and SOX1; and were able to differentiate into three neural lineage cells: neurons, astrocytes, and oligodendrocytes in vitro. Our transcriptome analyses revealed that the Wnt and Hedgehog signaling pathways regulate hPSCs cell fate decisions for neural lineages and maintain the self-renewal of CLNSCs. One interesting network could be the deregulation of the Wnt/β-catenin signaling pathway in CLNSCs via the downregulation of c-MYC, which may promote exit from pluripotency and neural differentiation. The Wnt-induced spinal markers HOXA1-4, HOXA7, HOXB1-4, and HOXC4 were increased, however, the brain markers FOXG1 and OTX2, were absent in the CLNSCs, indicating that CLNSCs have partial spinal cord properties. Finally, a CLNSC simple culture condition, when applied to hPSCs, supports the generation of NSCs, and provides a new and efficient cell model with which to untangle the mechanisms during neurogenesis.
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Germann M, Baker SN. Evidence for Subcortical Plasticity after Paired Stimulation from a Wearable Device. J Neurosci 2021; 41:1418-1428. [PMID: 33441436 PMCID: PMC7896019 DOI: 10.1523/jneurosci.1554-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 11/21/2022] Open
Abstract
Existing non-invasive stimulation protocols can generate plasticity in the motor cortex and its corticospinal projections; techniques for inducing plasticity in subcortical circuits and alternative descending pathways such as the reticulospinal tract (RST) are less well developed. One possible approach developed by this laboratory pairs electrical muscle stimulation with auditory clicks, using a wearable device to deliver stimuli during normal daily activities. In this study, we applied a variety of electrophysiological assessments to male and female healthy human volunteers during a morning and evening laboratory visit. In the intervening time (∼6 h), subjects wore the stimulation device, receiving three different protocols, in which clicks and stimulation of the biceps muscle were paired at either low or high rate, or delivered at random. Paired stimulation: (1) increased the extent of reaction time shortening by a loud sound (the StartReact effect); (2) decreased the suppression of responses to transcranial magnetic brain stimulation (TMS) following a loud sound; (3) enhanced muscle responses elicited by a TMS coil oriented to induce anterior-posterior (AP) current, but not posterior-anterior (PA) current, in the brain. These measurements have all been suggested to be sensitive to subcortical, possibly reticulospinal, activity. Changes were similar for either of the two paired stimulus rates tested, but absent after unpaired (control) stimulation. Taken together, these results suggest that pairing clicks and muscle stimulation for long periods does indeed induce plasticity in subcortical systems such as the RST.SIGNIFICANCE STATEMENT Subcortical systems such as the reticulospinal tract (RST) are important motor pathways, which can make a significant contribution to functional recovery after cortical damage such as stroke. Here, we measure changes produced after a novel non-invasive stimulation protocol, which uses a wearable device to stimulate for extended periods. We observed changes in electrophysiological measurements consistent with the induction of subcortical plasticity. This protocol may prove an important tool for enhancing motor rehabilitation, in situations where insufficient cortical tissue survives to be a plausible substrate for recovery of function.
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Affiliation(s)
- Maria Germann
- Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stuart N Baker
- Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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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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Kumru H, Flores Á, Rodríguez-Cañón M, Edgerton VR, García L, Benito-Penalva J, Navarro X, Gerasimenko Y, García-Alías G, Vidal J. Cervical Electrical Neuromodulation Effectively Enhances Hand Motor Output in Healthy Subjects by Engaging a Use-Dependent Intervention. J Clin Med 2021; 10:E195. [PMID: 33430460 PMCID: PMC7827883 DOI: 10.3390/jcm10020195] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/01/2021] [Accepted: 01/05/2021] [Indexed: 12/12/2022] Open
Abstract
Electrical enabling motor control (eEmc) through transcutaneous spinal cord stimulation is a non-invasive method that can modify the functional state of the sensory-motor system. We hypothesize that eEmc delivery, together with hand training, improves hand function in healthy subjects more than either intervention alone by inducing plastic changes at spinal and cortical levels. Ten voluntary participants were included in the following three interventions: (i) hand grip training, (ii) eEmc, and (iii) eEmc with hand training. Functional evaluation included the box and blocks test (BBT) and hand grip maximum voluntary contraction (MVC), spinal and cortical motor evoked potential (sMEP and cMEP), and resting motor thresholds (RMT), short interval intracortical inhibition (SICI), and F wave in the abductor pollicis brevis muscle. eEmc combined with hand training retained MVC and increased F wave amplitude and persistency, reduced cortical RMT and facilitated cMEP amplitude. In contrast, eEmc alone only increased F wave amplitude, whereas hand training alone reduced MVC and increased cortical RMT and SICI. In conclusion, eEmc combined with hand grip training enhanced hand motor output and induced plastic changes at spinal and cortical level in healthy subjects when compared to either intervention alone. These data suggest that electrical neuromodulation changes spinal and, perhaps, supraspinal networks to a more malleable state, while a concomitant use-dependent mechanism drives these networks to a higher functional state.
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Affiliation(s)
- Hatice Kumru
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - África Flores
- Departament de Biologia Cel·lular, Fisiologia i Immunologia & Insititute of Neuroscience, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, 08193 Barcelona, Spain; (Á.F.); (M.R.-C.)
| | - María Rodríguez-Cañón
- Departament de Biologia Cel·lular, Fisiologia i Immunologia & Insititute of Neuroscience, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, 08193 Barcelona, Spain; (Á.F.); (M.R.-C.)
| | - Victor R. Edgerton
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Loreto García
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Jesús Benito-Penalva
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Xavier Navarro
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Departament de Biologia Cel·lular, Fisiologia i Immunologia & Insititute of Neuroscience, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, 08193 Barcelona, Spain; (Á.F.); (M.R.-C.)
| | - Yury Gerasimenko
- Pavlov Institute of Physiology, 199034 St. Petersburg, Russia;
- Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40292, USA
| | - Guillermo García-Alías
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Departament de Biologia Cel·lular, Fisiologia i Immunologia & Insititute of Neuroscience, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, 08193 Barcelona, Spain; (Á.F.); (M.R.-C.)
| | - Joan Vidal
- Fundación Institut Guttmann, Institut Universitari de Neurorehabilitació Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain; (V.R.E.); (L.G.); (J.B.-P.); (X.N.); (G.G.-A.); (J.V.)
- Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
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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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Chiou SY, Strutton PH. Crossed Corticospinal Facilitation Between Arm and Trunk Muscles Correlates With Trunk Control After Spinal Cord Injury. Front Hum Neurosci 2020; 14:583579. [PMID: 33192418 PMCID: PMC7645046 DOI: 10.3389/fnhum.2020.583579] [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: 07/22/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: To investigate whether crossed corticospinal facilitation between arm and trunk muscles is preserved following spinal cord injury (SCI) and to elucidate these neural interactions for postural control during functional arm movements. Methods: Using transcranial magnetic stimulation (TMS) in 22 subjects with incomplete SCI motor evoked potentials (MEPs) in the erector spinae (ES) muscle were examined when the contralateral arm was at rest or performed 20% of maximal voluntary contraction (MVC) of biceps brachii (BB) or triceps brachii (TB). Trunk function was assessed with rapid shoulder flexion and forward-reaching tasks. Results: MEP amplitudes in ES were increased during elbow flexion in some subjects and this facilitatory effect was more prominent in subjects with thoracic SCI than in the subjects with cervical SCI. Those who showed the increased MEPs during elbow flexion had faster reaction times and quicker anticipatory postural adjustments of the trunk in the rapid shoulder flexion task. The onset of EMG activity in ES during the rapid shoulder flexion task correlated with the trunk excursion in forward-reaching. Conclusions: Our findings demonstrate that crossed corticospinal facilitation in the trunk muscles can be preserved after SCI and is reflected in trunk control during functional arm movements.
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Affiliation(s)
- Shin-Yi Chiou
- Sport, Exercise, and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.,The Nick Davey Laboratory, Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Paul H Strutton
- The Nick Davey Laboratory, Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom
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Qasem H, Fujiyama H, Rurak BK, Vallence AM. Good test–retest reliability of a paired-pulse transcranial magnetic stimulation protocol to measure short-interval intracortical facilitation. Exp Brain Res 2020; 238:2711-2723. [DOI: 10.1007/s00221-020-05926-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/15/2020] [Indexed: 12/21/2022]
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27
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Distinct Corticospinal and Reticulospinal Contributions to Voluntary Control of Elbow Flexor and Extensor Muscles in Humans with Tetraplegia. J Neurosci 2020; 40:8831-8841. [PMID: 32883710 DOI: 10.1523/jneurosci.1107-20.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/20/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
Humans with cervical spinal cord injury (SCI) often recover voluntary control of elbow flexors and, to a much lesser extent, elbow extensor muscles. The neural mechanisms underlying this asymmetrical recovery remain unknown. Anatomical and physiological evidence in animals and humans indicates that corticospinal and reticulospinal pathways differentially control elbow flexor and extensor motoneurons; therefore, it is possible that reorganization in these pathways contributes to the asymmetrical recovery of elbow muscles after SCI. To test this hypothesis, we examined motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the arm representation of the primary motor cortex, maximal voluntary contractions, the StartReact response (a shortening in reaction time evoked by a startling stimulus), and the effect of an acoustic startle cue on MEPs elicited by cervicomedullary stimulation (CMEPs) on biceps and triceps brachii in males and females with and without chronic cervical incomplete SCI. We found that SCI participants showed similar MEPs and maximal voluntary contractions in biceps but smaller responses in triceps compared with controls, suggesting reduced corticospinal inputs to elbow extensors. The StartReact and CMEP facilitation was larger in biceps but similar to controls in triceps, suggesting enhanced reticulospinal inputs to elbow flexors. These findings support the hypothesis that the recovery of biceps after cervical SCI results, at least in part, from increased reticulospinal inputs and that the lack of these extra inputs combined with the loss of corticospinal drive contribute to the pronounced weakness found in triceps.SIGNIFICANCE STATEMENT Although a number of individuals with cervical incomplete spinal cord injury show limited functional recovery of elbow extensors compared with elbow flexor muscles, to date, the neural mechanisms underlying this asymmetrical recovery remain unknown. Here, we provide for the first time evidence for increased reticulospinal inputs to biceps but not triceps brachii and loss of corticospinal drive to triceps brachii in humans with tetraplegia. We propose that this reorganization in descending control contributes to the asymmetrical recovery between elbow flexor and extensor muscles after cervical spinal cord injury.
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28
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Opie GM, Semmler JG. Characterising the influence of cerebellum on the neuroplastic modulation of intracortical motor circuits. PLoS One 2020; 15:e0236005. [PMID: 32649711 PMCID: PMC7351163 DOI: 10.1371/journal.pone.0236005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 06/19/2020] [Indexed: 11/19/2022] Open
Abstract
The cerebellum (CB) has extensive connections with both cortical and subcortical areas of the brain, and is known to strongly influence function in areas it projects to. In particular, research using non-invasive brain stimulation (NIBS) has shown that CB projections to primary motor cortex (M1) are likely important for facilitating the learning of new motor skills, and that this process may involve modulation of late indirect (I) wave inputs in M1. However, the nature of this relationship remains unclear, particularly in regards to how CB influences the contribution of the I-wave circuits to neuroplastic changes in M1. Within the proposed research, we will therefore investigate how CB effects neuroplasticity of the I-wave generating circuits. This will be achieved by downregulating CB excitability while concurrently applying a neuroplastic intervention that specifically targets the I-wave circuitry. The outcomes of this study will provide valuable neurophysiological insight into key aspects of the motor network, and may inform the development of optimized interventions for modifying motor learning in a targeted way.
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Affiliation(s)
- George M. Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
- * E-mail:
| | - John G. Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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29
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Jack AS, Hurd C, Martin J, Fouad K. Electrical Stimulation as a Tool to Promote Plasticity of the Injured Spinal Cord. J Neurotrauma 2020; 37:1933-1953. [PMID: 32438858 DOI: 10.1089/neu.2020.7033] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Unlike their peripheral nervous system counterparts, the capacity of central nervous system neurons and axons for regeneration after injury is minimal. Although a myriad of therapies (and different combinations thereof) to help promote repair and recovery after spinal cord injury (SCI) have been trialed, few have progressed from bench-top to bedside. One of the few such therapies that has been successfully translated from basic science to clinical applications is electrical stimulation (ES). Although the use and study of ES in peripheral nerve growth dates back nearly a century, only recently has it started to be used in a clinical setting. Since those initial experiments and seminal publications, the application of ES to restore function and promote healing have greatly expanded. In this review, we discuss the progression and use of ES over time as it pertains to promoting axonal outgrowth and functional recovery post-SCI. In doing so, we consider four major uses for the study of ES based on the proposed or documented underlying mechanism: (1) using ES to introduce an electric field at the site of injury to promote axonal outgrowth and plasticity; (2) using spinal cord ES to activate or to increase the excitability of neuronal networks below the injury; (3) using motor cortex ES to promote corticospinal tract axonal outgrowth and plasticity; and (4) leveraging the timing of paired stimuli to produce plasticity. Finally, the use of ES in its current state in the context of human SCI studies is discussed, in addition to ongoing research and current knowledge gaps, to highlight the direction of future studies for this therapeutic modality.
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Affiliation(s)
- Andrew S Jack
- Department of Neurological Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Caitlin Hurd
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - John Martin
- Department of Molecular, Cellular, and Biomedical Sciences, City University of New York School of Medicine, and City University of New York Graduate Center, New York, New York, USA
| | - Karim Fouad
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.,Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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30
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Opie GM, Hand BJ, Semmler JG. Age-related changes in late synaptic inputs to corticospinal neurons and their functional significance: A paired-pulse TMS study. Brain Stimul 2020; 13:239-246. [DOI: 10.1016/j.brs.2019.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 01/30/2023] Open
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31
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A Dynamical System Framework for Theorizing Preparatory Inhibition. J Neurosci 2019; 38:3391-3393. [PMID: 29618545 DOI: 10.1523/jneurosci.0069-18.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/20/2018] [Accepted: 02/23/2018] [Indexed: 11/21/2022] Open
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32
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Cho N, Squair JW, Bloch J, Courtine G. Neurorestorative interventions involving bioelectronic implants after spinal cord injury. Bioelectron Med 2019; 5:10. [PMID: 32232100 PMCID: PMC7098222 DOI: 10.1186/s42234-019-0027-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 06/13/2019] [Indexed: 12/15/2022] Open
Abstract
In the absence of approved treatments to repair damage to the central nervous system, the role of neurosurgeons after spinal cord injury (SCI) often remains confined to spinal cord decompression and vertebral fracture stabilization. However, recent advances in bioelectronic medicine are changing this landscape. Multiple neuromodulation therapies that target circuits located in the brain, midbrain, or spinal cord have been able to improve motor and autonomic functions. The spectrum of implantable brain-computer interface technologies is also expanding at a fast pace, and all these neurotechnologies are being progressively embedded within rehabilitation programs in order to augment plasticity of spared circuits and residual projections with training. Here, we summarize the impending arrival of bioelectronic medicine in the field of SCI. We also discuss the new role of functional neurosurgeons in neurorestorative interventional medicine, a new discipline at the intersection of neurosurgery, neuro-engineering, and neurorehabilitation.
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Affiliation(s)
- Newton Cho
- École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Center for Neuroprosthetics and Brain Mind Institute, 1202 Genève, Switzerland.,2Department of Neurosurgery, University of Toronto, Toronto, Ontario Canada
| | - Jordan W Squair
- École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Center for Neuroprosthetics and Brain Mind Institute, 1202 Genève, Switzerland.,3Cumming School of Medicine, University of Calgary, Calgary, Canada.,4MD/PhD Training Program, University of British Columbia, Vancouver, Canada
| | - Jocelyne Bloch
- 5Department of Neurosurgery, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.,6Defitech Center for Interventional Neurotherapies, EPFL / CHUV, Lausanne, Switzerland
| | - Grégoire Courtine
- École polytechnique fédérale de Lausanne (EPFL), Campus Biotech, Center for Neuroprosthetics and Brain Mind Institute, 1202 Genève, Switzerland.,5Department of Neurosurgery, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.,6Defitech Center for Interventional Neurotherapies, EPFL / CHUV, Lausanne, Switzerland
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Courtine G, Sofroniew MV. Spinal cord repair: advances in biology and technology. Nat Med 2019; 25:898-908. [PMID: 31160817 DOI: 10.1038/s41591-019-0475-6] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
Individuals with spinal cord injury (SCI) can face decades with permanent disabilities. Advances in clinical management have decreased morbidity and improved outcomes, but no randomized clinical trial has demonstrated the efficacy of a repair strategy for improving recovery from SCI. Here, we summarize recent advances in biological and engineering strategies to augment neuroplasticity and/or functional recovery in animal models of SCI that are pushing toward clinical translation.
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Affiliation(s)
- Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland. .,Department of Neurosurgery, University Hospital Lausanne (CHUV), Lausanne, Switzerland.
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
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34
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Jo HJ, Perez MA. Changes in motor-evoked potential latency during grasping after tetraplegia. J Neurophysiol 2019; 122:1675-1684. [PMID: 30673355 DOI: 10.1152/jn.00671.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The corticospinal pathway contributes to the control of grasping in intact humans. After spinal cord injury (SCI), there is an extensive reorganization in the corticospinal pathway; however, its contribution to the control of grasping after the injury remains poorly understood. We addressed this question by using transcranial magnetic stimulation (TMS) over the hand representation of the motor cortex to elicit motor-evoked potentials (MEPs) in an intrinsic finger muscle during precision grip and power grip with the TMS coil oriented to induce currents in the brain in the latero-medial (LM) direction to activate corticospinal axons directly and in the posterior-anterior (PA) and anterior-posterior (AP) directions to activate the axon indirectly through synaptic inputs in humans with and without cervical incomplete SCI. We found prolonged MEP latencies in all coil orientations in both tasks in SCI compared with control subjects. The latencies of MEPs elicited by AP relative to LM stimuli were consistently longer during power compared with precision grip in controls and SCI subjects. In contrast, PA relative to LM MEP latencies were similar between tasks across groups. Central conduction time of AP MEPs was prolonged during power compared with precision grip in controls and SCI participants. Our results support evidence indicating that inputs activated by AP and PA currents are engaged to a different extent during fine and gross grasping in humans with and without SCI.NEW & NOTEWORTHY The mechanisms contributing to the control of hand function in humans with spinal cord injury (SCI) remain poorly understood. Here, we demonstrate for the first time that the latency of corticospinal responses elicited by transcranial magnetic stimulation anterior-posterior induced currents, relative to latero-medial currents, was prolonged during power compared with precision grip in humans with and without SCI. Gross grasping might represent a stragegy to engage networks activated by anterior-posterior currents after SCI.
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Affiliation(s)
- Hang Jin Jo
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, Florida.,Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, Florida
| | - Monica A Perez
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, Florida.,Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, Florida
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35
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Thompson AK, Fiorenza G, Smyth L, Favale B, Brangaccio J, Sniffen J. Operant conditioning of the motor-evoked potential and locomotion in people with and without chronic incomplete spinal cord injury. J Neurophysiol 2019; 121:853-866. [PMID: 30625010 DOI: 10.1152/jn.00557.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Foot drop is very common among people with chronic incomplete spinal cord injury (SCI) and likely stems from SCI that disturbs the corticospinal activation of the ankle dorsiflexor tibialis anterior (TA). Thus, if one can recover or increase the corticospinal excitability reduced by SCI, motor function recovery may be facilitated. Here, we hypothesized that in people suffering from weak dorsiflexion due to chronic incomplete SCI, increasing the TA motor-evoked potential (MEP) through operant up-conditioning can improve dorsiflexion during locomotion, while in people without any injuries, it would have little impact on already normal locomotion. Before and after 24 MEP conditioning or control sessions, locomotor electromyography (EMG) and kinematics were measured. This study reports the results of these locomotor assessments. In participants without SCI, locomotor EMG activity, soleus Hoffmann reflex modulation, and joint kinematics did not change, indicating that MEP up-conditioning or repeated single-pulse transcranial magnetic stimulation (i.e., control protocol) does not influence normal locomotion. In participants with SCI, MEP up-conditioning increased TA activity during the swing-to-swing stance transition phases and ankle joint motion during locomotion in the conditioned leg and increased walking speed consistently. In addition, the swing-phase TA activity and ankle joint motion also improved in the contralateral leg. The results are consistent with our hypothesis. Together with the previous operant conditioning studies in humans and rats, the present study suggests that operant conditioning can be a useful therapeutic tool for enhancing motor function recovery in people with SCI and other central nervous system disorders. NEW & NOTEWORTHY This study examined the functional impact of operant conditioning of motor-evoked potential (MEP) to transcranial magnetic stimulation that aimed to increase corticospinal excitability for the ankle dorsiflexor tibialis anterior (TA). In people with chronic incomplete spinal cord injury (SCI), MEP up-conditioning increased TA activity and improved dorsiflexion during locomotion, while in people without injuries, it had little impact on already normal locomotion. MEP conditioning may potentially be used to enhance motor function recovery after SCI.
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Affiliation(s)
- Aiko K Thompson
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina , Charleston, South Carolina
| | - Gina Fiorenza
- United Technologies Aerospace Systems, Windsor Locks, Connecticut
| | - Lindsay Smyth
- Helen Hayes Hospital, New York State Department of Health, West Haverstraw, New York
| | - Briana Favale
- Helen Hayes Hospital, New York State Department of Health, West Haverstraw, New York
| | - Jodi Brangaccio
- Helen Hayes Hospital, New York State Department of Health, West Haverstraw, New York
| | - Janice Sniffen
- Department of Physical Therapy, School of Health Technology and Management, Stony Brook University , Stony Brook, New York
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36
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Si Y, Wu X, Li F, Zhang L, Duan K, Li P, Song L, Jiang Y, Zhang T, Zhang Y, Chen J, Gao S, Biswal B, Yao D, Xu P. Different Decision-Making Responses Occupy Different Brain Networks for Information Processing: A Study Based on EEG and TMS. Cereb Cortex 2018; 29:4119-4129. [PMID: 30535319 DOI: 10.1093/cercor/bhy294] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/14/2018] [Accepted: 11/02/2018] [Indexed: 01/31/2023] Open
Abstract
Abstract
This study used large-scale time-varying network analysis to reveal the diverse network patterns during the different decision stages and found that the responses of rejection and acceptance involved different network structures. When participants accept unfair offers, the brain recruits a more bottom-up mechanism with a much stronger information flow from the visual cortex (O2) to the frontal area, but when they reject unfair offers, it displayed a more top-down flow derived from the frontal cortex (Fz) to the parietal and occipital cortices. Furthermore, we performed 2 additional studies to validate the above network models: one was to identify the 2 responses based on the out-degree information of network hub nodes, which results in 70% accuracy, and the other utilized theta burst stimulation (TBS) of transcranial magnetic stimulation (TMS) to modulate the frontal area before the decision-making tasks. We found that the intermittent TBS group demonstrated lower acceptance rates and that the continuous TBS group showed higher acceptance rates compared with the sham group. Similar effects were not observed after TBS of a control site. These results suggest that the revealed decision-making network model can serve as a potential intervention model to alter decision responses.
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Affiliation(s)
- Yajing Si
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Xi Wu
- Business School, Sichuan Normal University, Chengdu 610101, China
| | - Fali Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Luyan Zhang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Keyi Duan
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Peiyang Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Limeng Song
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yuanling Jiang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Tao Zhang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
- Center for Mental Health Development and Research, Xihua University, Chengdu 610039, China
| | - Yangsong Zhang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Computer Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Jing Chen
- Research Center of Psychological Development and Application, Sichuan Normal University, Chengdu 610101, China
| | - Shan Gao
- School of Foreign Languages, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Bharat Biswal
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Dezhong Yao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Peng Xu
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
- School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, China
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Jo HJ, Di Lazzaro V, Perez MA. Effect of coil orientation on motor-evoked potentials in humans with tetraplegia. J Physiol 2018; 596:4909-4921. [PMID: 29923194 DOI: 10.1113/jp275798] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Although corticospinal function changes following spinal cord injury (SCI), the extent to which we can activate the corticospinal tract after injury remains poorly understood. To address this question, we used transcranial magnetic stimulation over the hand representation of the primary motor cortex to elicit motor-evoked potentials (MEPs) using posterior-anterior and anterior-posterior induced currents in the brain and compared them with responses evoked using lateral-medial currents in participants with and without cervical incomplete SCI during small levels of index finger abduction. We found prolonged MEP latencies in all coil orientations in SCI compared to control subjects. However, the latencies of MEPs elicited by posterior-anterior and anterior-posterior compared to lateral-medial stimulation were shorter in SCI compared to controls, particularly for MEPs elicited by anterior-posterior currents. Our findings demonstrate for the first time that corticospinal responses elicited by different directions of the induced current in the brain are differentially affected after SCI. ABSTRACT The corticospinal tract undergoes reorganization following spinal cord injury (SCI). However, the extent to which we can activate corticospinal neurons using non-invasive stimulation after injury remains poorly understood. To address this question, we used transcranial magnetic stimulation over the hand representation of the primary motor cortex to elicit motor-evoked potentials (MEPs) using posterior-anterior (PA) and anterior-posterior (AP) induced currents in the brain and compared them with the responses evoked by direct activation of corticospinal axons using lateral-medial (LM) currents. Testing was completed during small levels of index finger abduction in humans with and without (controls) cervical incomplete SCI. We found prolonged MEP latencies in individuals with SCI in all coil orientations compared to controls. However, latencies of MEPs elicited by PA and AP stimulation relative to those elicited by LM stimulation were shorter in SCI compared to control subjects. Notably, the largest difference between SCI and control subjects was present in MEPs elicited by AP currents. Using a novel controllable pulse parameter transcranial magnetic stimulation, we also found that MEPs elicited by AP currents with 30 μs compared to 60 and 120 μs pulse width had increased latency in controls but not in SCI subjects. Our findings demonstrate that differences between corticospinal responses elicited by AP and PA induced currents were not preserved in humans with tetraplegia and suggest that neural structures activated by AP currents change largely after the injury.
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Affiliation(s)
- Hang Jin Jo
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, FL, USA.,Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL, USA
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Monica A Perez
- University of Miami, Department of Neurological Surgery, The Miami Project to Cure Paralysis, Miami, FL, USA.,Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL, USA
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Thompson AK, Cote RH, Sniffen JM, Brangaccio JA. Operant conditioning of the tibialis anterior motor evoked potential in people with and without chronic incomplete spinal cord injury. J Neurophysiol 2018; 120:2745-2760. [PMID: 30207863 DOI: 10.1152/jn.00362.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The activity of corticospinal pathways is important in movement control, and its plasticity is essential for motor skill learning and re-learning after central nervous system (CNS) injuries. Therefore, enhancing the corticospinal function may improve motor function recovery after CNS injuries. Operant conditioning of stimulus-induced muscle responses (e.g., reflexes) is known to induce the targeted plasticity in a targeted pathway. Thus, an operant conditioning protocol to target the corticospinal pathways may be able to enhance the corticospinal function. To test this possibility, we investigated whether operant conditioning of the tibialis anterior (TA) motor evoked potential (MEP) to transcranial magnetic stimulation can enhance corticospinal excitability in people with and without chronic incomplete spinal cord injury (SCI). The protocol consisted of 6 baseline and 24 up-conditioning/control sessions over 10 wk. In all sessions, TA MEPs were elicited at 10% above active MEP threshold while the sitting participant provided a fixed preset level of TA background electromyographic activity. During baseline sessions, MEPs were simply measured. During conditioning trials of the conditioning sessions, the participant was encouraged to increase MEP and was given immediate feedback indicating whether MEP size was above a criterion. In 5/8 participants without SCI and 9/10 with SCI, over 24 up-conditioning sessions, MEP size increased significantly to ~150% of the baseline value, whereas the silent period (SP) duration decreased by ~20%. In a control group of participants without SCI, neither MEP nor SP changed. These results indicate that MEP up-conditioning can facilitate corticospinal excitation, which is essential for enhancing motor function recovery after SCI. NEW & NOTEWORTHY We investigated whether operant conditioning of the motor evoked potential (MEP) to transcranial magnetic stimulation can systematically increase corticospinal excitability for the ankle dorsiflexor tibialis anterior (TA) in people with and without chronic incomplete spinal cord injury. We found that up-conditioning can increase the TA MEP while reducing the accompanying silent period (SP) duration. These findings suggest that MEP up-conditioning produces the facilitation of corticospinal excitation as targeted, whereas it suppresses inhibitory mechanisms reflected in SP.
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Affiliation(s)
- Aiko K Thompson
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina , Charleston, South Carolina
| | - Rachel H Cote
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina , Charleston, South Carolina
| | - Janice M Sniffen
- Department of Physical Therapy, School of Health Technology and Management, Stony Brook University , Stony Brook, New York
| | - Jodi A Brangaccio
- Helen Hayes Hospital, New York State Department of Health, West Haverstraw, New York
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Christiansen L, Perez MA. Targeted-Plasticity in the Corticospinal Tract After Human Spinal Cord Injury. Neurotherapeutics 2018; 15:618-627. [PMID: 29946981 PMCID: PMC6095776 DOI: 10.1007/s13311-018-0639-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spinal cord injury (SCI) often results in impaired or absent sensorimotor function below the level of the lesion. Recent electrophysiological studies in humans with chronic incomplete SCI demonstrate that voluntary motor output can be to some extent potentiated by noninvasive stimulation that targets the corticospinal tract. We discuss emerging approaches that use transcranial magnetic stimulation (TMS) over the primary motor cortex and electrical stimulation over a peripheral nerve as tools to induce plasticity in residual corticospinal projections. A single TMS pulse over the primary motor cortex has been paired with peripheral nerve electrical stimulation at precise interstimulus intervals to reinforce corticospinal synaptic transmission using principles of spike-timing dependent plasticity. Pairs of TMS pulses have also been used at interstimulus intervals that mimic the periodicity of descending indirect (I) waves volleys in the corticospinal tract. This data, along with information about the extent of the injury, provides a new framework for exploring the contribution of the corticospinal tract to recovery of function following SCI.
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Affiliation(s)
- Lasse Christiansen
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami, Miami, FL, 33136, USA
- Bruce W. Carter Department of Veterans Affairs Medical Center, 1201 NW 16th Street, Miami, FL, 33125, USA
| | - Monica A Perez
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami, Miami, FL, 33136, USA.
- Bruce W. Carter Department of Veterans Affairs Medical Center, 1201 NW 16th Street, Miami, FL, 33125, USA.
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Opie GM, Cirillo J, Semmler JG. Age-related changes in late I-waves influence motor cortex plasticity induction in older adults. J Physiol 2018; 596:2597-2609. [PMID: 29667190 DOI: 10.1113/jp274641] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 04/16/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The response to neuroplasticity interventions using transcranial magnetic stimulation (TMS) is reduced in older adults, which may be due, in part, to age-related alterations in interneuronal (I-wave) circuitry. The current study investigated age-related changes in interneuronal characteristics and whether they influence motor cortical plasticity in older adults. While I-wave recruitment was unaffected by age, there was a shift in the temporal characteristics of the late, but not the early I-waves. Using I-wave periodicity repetitive TMS (iTMS), we showed that these differences in I-wave characteristics influence the induction of cortical plasticity in older adults. ABSTRACT Previous research shows that neuroplasticity assessed using transcranial magnetic stimulation (TMS) is reduced in older adults. While this deficit is often assumed to represent altered synaptic modification processes, age-related changes in the interneuronal circuits activated by TMS may also contribute. Here we assessed age-related differences in the characteristics of the corticospinal indirect (I) waves and how they influence plasticity induction in primary motor cortex. Twenty young (23.7 ± 3.4 years) and 19 older adults (70.6 ± 6.0 years) participated in these studies. I-wave recruitment was assessed by changing the direction of the current used to activate the motor cortex, whereas short-interval intracortical facilitation (SICF) was recorded to assess facilitatory I-wave interactions. In a separate study, I-wave periodicity TMS (iTMS) was used to examine the effect of I-wave latency on motor cortex plasticity. Data from the motor-evoked potential (MEP) onset latency produced using different coil orientations suggested that there were no age-related differences in preferential I-wave recruitment (P = 0.6). However, older adults demonstrated significant reductions in MEP facilitation at all 3 SICF peaks (all P values < 0.05) and a delayed latency of the second and third SICF peaks (all P values < 0.05). Using I-wave intervals that were optimal for young and older adults, these changes in the late I-waves were shown to influence the plasticity response in older adults after iTMS. These findings suggest that temporal characteristics are delayed for the late I-waves in older adults, and that optimising TMS interventions based on I-wave characteristics may improve the plasticity response in older adults.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John Cirillo
- Movement Neuroscience Laboratory, Department of Exercise Sciences, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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Potentiating paired corticospinal-motoneuronal plasticity after spinal cord injury. Brain Stimul 2018; 11:1083-1092. [PMID: 29848448 DOI: 10.1016/j.brs.2018.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Paired corticospinal-motoneuronal stimulation (PCMS) increases corticospinal transmission in humans with chronic incomplete spinal cord injury (SCI). OBJECTIVE/HYPOTHESIS Here, we examine whether increases in the excitability of spinal motoneurons, by performing voluntary activity, could potentiate PCMS effects on corticospinal transmission. METHODS During PCMS, we used 100 pairs of stimuli where corticospinal volleys evoked by transcranial magnetic stimulation (TMS) over the hand representation of the primary motor cortex were timed to arrive at corticospinal-motoneuronal synapses of the first dorsal interosseous (FDI) muscle ∼1-2 ms before antidromic potentials were elicited in motoneurons by electrical stimulation of the ulnar nerve. PCMS was applied at rest (PCMSrest) and during a small level of isometric index finger abduction (PCMSactive) on separate days. Motor evoked potentials (MEPs) elicited by TMS and electrical stimulation were measured in the FDI muscle before and after each protocol in humans with and without (controls) chronic cervical SCI. RESULTS We found in control participants that MEPs elicited by TMS and electrical stimulation increased to a similar extent after both PCMS protocols for ∼30 min. Whereas, in humans with SCI, MEPs elicited by TMS and electrical stimulation increased to a larger extent after PCMSactive compared with PCMSrest. Importantly, SCI participants who did not respond to PCMSrest responded after PCMSactive and those who responded to both protocols showed larger increments in corticospinal transmission after PCMSactive. CONCLUSIONS Our findings suggest that muscle contraction during PCMS potentiates corticospinal transmission. PCMS applied during voluntary activity may represent a strategy to boost spinal plasticity after SCI.
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Hodkin EF, Lei Y, Humby J, Glover IS, Choudhury S, Kumar H, Perez MA, Rodgers H, Jackson A. Automated FES for Upper Limb Rehabilitation Following Stroke and Spinal Cord Injury. IEEE Trans Neural Syst Rehabil Eng 2018; 26:1067-1074. [PMID: 29752242 PMCID: PMC6051484 DOI: 10.1109/tnsre.2018.2816238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/20/2018] [Accepted: 03/01/2018] [Indexed: 11/07/2022]
Abstract
Neurorehabilitation aims to induce beneficial neural plasticity in order to restore function following injury to the nervous system. There is an increasing evidence that appropriately timed functional electrical stimulation (FES) can promote associative plasticity, but the dosage is critical for lasting functional benefits. Here, we present a novel approach to closed-loop control of muscle stimulation for the rehabilitation of reach-to-grasp movements following stroke and spinal cord injury (SCI). We developed a simple, low-cost device to deliver assistive stimulation contingent on users' self-initiated movements. The device allows repeated practice with minimal input by a therapist, and is potentially suitable for home use. Pilot data demonstrate usability by people with upper limb weakness following SCI and stroke, and participant feedback was positive. Moreover, repeated training with the device over 1-2 weeks led to functional benefits on a general object manipulation assessment. Thus, automated FES delivered by this novel device may provide a promising and readily translatable therapy for upper limb rehabilitation for people with stroke and SCI.
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Central nervous system microstimulation: Towards selective micro-neuromodulation. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017. [DOI: 10.1016/j.cobme.2017.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Gunduz A, Rothwell J, Vidal J, Kumru H. Non-invasive brain stimulation to promote motor and functional recovery following spinal cord injury. Neural Regen Res 2017; 12:1933-1938. [PMID: 29323025 PMCID: PMC5784334 DOI: 10.4103/1673-5374.221143] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We conducted a systematic review of studies using non-invasive brain stimulation (NIBS: repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS)) as a research and clinical tool aimed at improving motor and functional recovery or spasticity in patients following spinal cord injury (SCI) under the assumption that if the residual corticospinal circuits could be stimulated appropriately, the changes might be accompanied by functional recovery or an improvement in spasticity. This review summarizes the literature on the changes induced by NIBS in the motor and functional recovery and spasticity control of the upper and lower extremities following SCI.
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Affiliation(s)
- Aysegul Gunduz
- Department of Neurology, Cerrahpasa School of Medicine, Istanbul University, Istanbul, Turkey
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, University College London, London, UK
| | - Joan Vidal
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, Badalona-Barcelona; Universidad Autonoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain
| | - Hatice Kumru
- Institut Guttmann, Institut Universitari de Neurorehabilitació adscrit a la UAB, Badalona-Barcelona; Universidad Autonoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona, Barcelona, Spain
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