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Billot A, Kiran S. Disentangling neuroplasticity mechanisms in post-stroke language recovery. BRAIN AND LANGUAGE 2024; 251:105381. [PMID: 38401381 PMCID: PMC10981555 DOI: 10.1016/j.bandl.2024.105381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/28/2023] [Accepted: 01/12/2024] [Indexed: 02/26/2024]
Abstract
A major objective in post-stroke aphasia research is to gain a deeper understanding of neuroplastic mechanisms that drive language recovery, with the ultimate goal of enhancing treatment outcomes. Subsequent to recent advances in neuroimaging techniques, we now have the ability to examine more closely how neural activity patterns change after a stroke. However, the way these neural activity changes relate to language impairments and language recovery is still debated. The aim of this review is to provide a theoretical framework to better investigate and interpret neuroplasticity mechanisms underlying language recovery in post-stroke aphasia. We detail two sets of neuroplasticity mechanisms observed at the synaptic level that may explain functional neuroimaging findings in post-stroke aphasia recovery at the network level: feedback-based homeostatic plasticity and associative Hebbian plasticity. In conjunction with these plasticity mechanisms, higher-order cognitive control processes dynamically modulate neural activity in other regions to meet communication demands, despite reduced neural resources. This work provides a network-level neurobiological framework for understanding neural changes observed in post-stroke aphasia and can be used to define guidelines for personalized treatment development.
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Affiliation(s)
- Anne Billot
- Center for Brain Recovery, Boston University, Boston, USA; Department of Psychology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Swathi Kiran
- Center for Brain Recovery, Boston University, Boston, USA.
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Fadli RA, Yamanouchi Y, Jovanovic LI, Popovic MR, Marquez-Chin C, Nomura T, Milosevic M. Effectiveness of motor and prefrontal cortical areas for brain-controlled functional electrical stimulation neuromodulation. J Neural Eng 2023; 20:056022. [PMID: 37714143 DOI: 10.1088/1741-2552/acfa22] [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: 03/23/2023] [Accepted: 09/15/2023] [Indexed: 09/17/2023]
Abstract
Objective. Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) could excite the central nervous system to enhance upper limb motor recovery. Our current study assessed the effectiveness of motor and prefrontal cortical activity-based BCI-FES to help elucidate the underlying neuromodulation mechanisms of this neurorehabilitation approach.Approach. The primary motor cortex (M1) and prefrontal cortex (PFC) BCI-FES interventions were performed for 25 min on separate days with twelve non-disabled participants. During the interventions, a single electrode from the contralateral M1 or PFC was used to detect event-related desynchronization (ERD) in the calibrated frequency range. If the BCI system detected ERD within 15 s of motor imagery, FES activated wrist extensor muscles. Otherwise, if the BCI system did not detect ERD within 15 s, a subsequent trial was initiated without FES. To evaluate neuromodulation effects, corticospinal excitability was assessed using single-pulse transcranial magnetic stimulation, and cortical excitability was assessed by motor imagery ERD and resting-state functional connectivity before, immediately, 30 min, and 60 min after each intervention.Main results. M1 and PFC BCI-FES interventions had similar success rates of approximately 80%, while the M1 intervention was faster in detecting ERD activity. Consequently, only the M1 intervention effectively elicited corticospinal excitability changes for at least 60 min around the targeted cortical area in the M1, suggesting a degree of spatial localization. However, cortical excitability measures did not indicate changes after either M1 or PFC BCI-FES.Significance. Neural mechanisms underlying the effectiveness of BCI-FES neuromodulation may be attributed to the M1 direct corticospinal projections and/or the closer timing between ERD detection and FES, which likely enhanced Hebbian-like plasticity by synchronizing cortical activation detected by the BCI system with the sensory nerve activation and movement related reafference elicited by FES.
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Affiliation(s)
- Rizaldi A Fadli
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, FL 33146, United States of America
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, United States of America
| | - Yuki Yamanouchi
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan
| | - Lazar I Jovanovic
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute-University Health Network, 520 Sutherland Drive, Toronto, Ontario M4G 3V9, Canada
| | - Milos R Popovic
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute-University Health Network, 520 Sutherland Drive, Toronto, Ontario M4G 3V9, Canada
- CRANIA, University Health Network & University of Toronto. 550 University Avenue, Toronto, Ontario M5G 2A2, Canada
| | - Cesar Marquez-Chin
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute-University Health Network, 520 Sutherland Drive, Toronto, Ontario M4G 3V9, Canada
- CRANIA, University Health Network & University of Toronto. 550 University Avenue, Toronto, Ontario M5G 2A2, Canada
| | - Taishin Nomura
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan
| | - Matija Milosevic
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531, Japan
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, FL 33146, United States of America
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, United States of America
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Sun W, Wu Q, Gao L, Zheng Z, Xiang H, Yang K, Yu B, Yao J. Advancements in Transcranial Magnetic Stimulation Research and the Path to Precision. Neuropsychiatr Dis Treat 2023; 19:1841-1851. [PMID: 37641588 PMCID: PMC10460597 DOI: 10.2147/ndt.s414782] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/02/2023] [Indexed: 08/31/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) has become increasingly popular in clinical practice in recent years, and there have been significant advances in the principles and stimulation modes of TMS. With the development of multi-mode and precise stimulation technology, it is crucial to have a comprehensive understanding of TMS. The neuroregulatory effects of TMS can vary depending on the specific mode of stimulation, highlighting the importance of exploring these effects through multimodal application. Additionally, the use of precise TMS therapy can help enhance our understanding of the neural mechanisms underlying these effects, providing us with a more comprehensive perspective. This article aims to review the mechanism of action, stimulation mode, multimodal application, and precision of TMS.
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Affiliation(s)
- Wei Sun
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
| | - Qiao Wu
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
| | - Li Gao
- Department of Neurology, The Third People’s Hospital of Chengdu, Chengdu Institute of Neurological Diseases, Chengdu City, Sichuan Province, People’s Republic of China
| | - Zhong Zheng
- Neurobiological Detection Center, West China Hospital Affiliated to Sichuan University, Chengdu City, Sichuan Province, People’s Republic of China
| | - Hu Xiang
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
| | - Kun Yang
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
| | - Bo Yu
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
| | - Jing Yao
- Department of Psychiatry, the Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang City, Sichuan Province, People’s Republic of China
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Duchet B, Bick C, Byrne Á. Mean-Field Approximations With Adaptive Coupling for Networks With Spike-Timing-Dependent Plasticity. Neural Comput 2023; 35:1481-1528. [PMID: 37437202 PMCID: PMC10422128 DOI: 10.1162/neco_a_01601] [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: 07/17/2022] [Accepted: 04/26/2023] [Indexed: 07/14/2023]
Abstract
Understanding the effect of spike-timing-dependent plasticity (STDP) is key to elucidating how neural networks change over long timescales and to design interventions aimed at modulating such networks in neurological disorders. However, progress is restricted by the significant computational cost associated with simulating neural network models with STDP and by the lack of low-dimensional description that could provide analytical insights. Phase-difference-dependent plasticity (PDDP) rules approximate STDP in phase oscillator networks, which prescribe synaptic changes based on phase differences of neuron pairs rather than differences in spike timing. Here we construct mean-field approximations for phase oscillator networks with STDP to describe part of the phase space for this very high-dimensional system. We first show that single-harmonic PDDP rules can approximate a simple form of symmetric STDP, while multiharmonic rules are required to accurately approximate causal STDP. We then derive exact expressions for the evolution of the average PDDP coupling weight in terms of network synchrony. For adaptive networks of Kuramoto oscillators that form clusters, we formulate a family of low-dimensional descriptions based on the mean-field dynamics of each cluster and average coupling weights between and within clusters. Finally, we show that such a two-cluster mean-field model can be fitted to synthetic data to provide a low-dimensional approximation of a full adaptive network with symmetric STDP. Our framework represents a step toward a low-dimensional description of adaptive networks with STDP, and could for example inform the development of new therapies aimed at maximizing the long-lasting effects of brain stimulation.
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Affiliation(s)
- Benoit Duchet
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford X3 9DU, U.K
- MRC Brain Network Dynamics Unit, University of Oxford, Oxford X1 3TH, U.K.
| | - Christian Bick
- Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam 1081 HV, the Netherlands
- Amsterdam Neuroscience-Systems and Network Neuroscience, Amsterdam 1081 HV, the Netherlands
- Mathematical Institute, University of Oxford, Oxford X2 6GG, U.K.
| | - Áine Byrne
- School of Mathematics and Statistics, University College Dublin, Dublin D04 V1W8, Ireland
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Brain and spinal cord paired stimulation coupled with locomotor training affects polysynaptic flexion reflex circuits in human spinal cord injury. Exp Brain Res 2022; 240:1687-1699. [PMID: 35513720 DOI: 10.1007/s00221-022-06375-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 04/15/2022] [Indexed: 12/19/2022]
Abstract
Neurorecovery from locomotor training is well established in human spinal cord injury (SCI). However, neurorecovery resulting from combined interventions has not been widely studied. In this randomized clinical trial, we established the tibialis anterior (TA) flexion reflex modulation pattern when transcranial magnetic stimulation (TMS) of the primary motor cortex was paired with transcutaneous spinal cord (transspinal) stimulation over the thoracolumbar region during assisted step training. Single pulses of TMS were delivered either before (TMS-transspinal) or after (transspinal-TMS) transspinal stimulation during the stance phase of the less impaired leg. Eight individuals with chronic incomplete or complete SCI received at least 20 sessions of paired stimulation during assisted step training. Each session consisted of 240 paired stimuli delivered over 10-min blocks for 1 h during robotic-assisted step training with the Lokomat6 Pro®. Body weight support, leg guidance force and treadmill speed were adjusted based on each participant's ability to step without knee buckling or toe dragging. Both the early and late TA flexion reflex remained unaltered after TMS-transspinal and locomotor training. In contrast, the early and late TA flexion reflexes were significantly depressed during stepping after transspinal-TMS and locomotor training. Reflex changes occurred at similar slopes and intercepts before and after training. Our findings support that targeted brain and spinal cord stimulation coupled with locomotor training reorganizes the function of flexion reflex pathways, which are a part of locomotor networks, in humans with varying levels of sensorimotor function after SCI.Trial registration number NCT04624607; Registered on November 12, 2020.
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Rosso C, Moulton EJ, Kemlin C, Leder S, Corvol JC, Mehdi S, Obadia MA, Obadia M, Yger M, Meseguer E, Perlbarg V, Valabregue R, Magno S, Lindberg P, Meunier S, Lamy JC. Cerebello-Motor Paired Associative Stimulation and Motor Recovery in Stroke: a Randomized, Sham-Controlled, Double-Blind Pilot Trial. Neurotherapeutics 2022; 19:491-500. [PMID: 35226342 PMCID: PMC9226244 DOI: 10.1007/s13311-022-01205-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2022] [Indexed: 12/27/2022] Open
Abstract
Cerebellum is a key structure for functional motor recovery after stroke. Enhancing the cerebello-motor pathway by paired associative stimulation (PAS) might improve upper limb function. Here, we conducted a randomized, double-blind, sham-controlled pilot trial investigating the efficacy of a 5-day treatment of cerebello-motor PAS coupled with physiotherapy for promoting upper limb motor function compared to sham stimulation. The secondary objectives were to determine in the active treated group (i) whether improvement of upper limb motor function was associated with changes in corticospinal excitability or changes in functional activity in the primary motor cortex and (ii) whether improvements were correlated to the structural integrity of the input and output pathways. To that purpose, hand dexterity and maximal grip strength were assessed along with TMS recordings and multimodal magnetic resonance imaging, before the first treatment, immediately after the last one and a month later. Twenty-seven patients were analyzed. Cerebello-motor PAS was effective compared to sham in improving hand dexterity (p: 0.04) but not grip strength. This improvement was associated with increased activation in the ipsilesional primary motor cortex (p: 0.04). Moreover, the inter-individual variability in clinical improvement was partly explained by the structural integrity of the afferent (p: 0.06) and efferent pathways (p: 0.02) engaged in this paired associative stimulation (i.e., cortico-spinal and dentato-thalamo-cortical tracts). In conclusion, cerebello-motor-paired associative stimulation combined with physiotherapy might be a promising approach to enhance upper limb motor function after stroke.Clinical Trial Registration URL: http://www.clinicaltrials.gov . Unique identifier: NCT02284087.
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Affiliation(s)
- Charlotte Rosso
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France.
- ICM Infrastructure Stroke Network, STAR Team, Hôpital Pitié-Salpêtrière, 75013, Paris, France.
- AP-HP, Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, DMU Neuroscience 6, 47-83 Boulevard de l'Hôpital, 75013, Paris, France.
| | - Eric Jr Moulton
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- ICM Infrastructure Stroke Network, STAR Team, Hôpital Pitié-Salpêtrière, 75013, Paris, France
| | - Claire Kemlin
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- ICM Infrastructure Stroke Network, STAR Team, Hôpital Pitié-Salpêtrière, 75013, Paris, France
| | - Sara Leder
- AP-HP, Urgences Cérébro-Vasculaires, Hôpital Pitié-Salpêtrière, DMU Neuroscience 6, 47-83 Boulevard de l'Hôpital, 75013, Paris, France
| | - Jean-Christophe Corvol
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- ICM Infrastructure Stroke Network, STAR Team, Hôpital Pitié-Salpêtrière, 75013, Paris, France
- AP-HP, Hôpital Pitié-Salpêtrière, Département de neurologieDMU Neuroscience 6, 75013, Paris, France
| | - Sophien Mehdi
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- Centre de Neuro-Imagerie de Recherche, Institut du Cerveau, CENIR, Paris Brain Institute - ICM, 75013, Paris, France
| | - Mickael A Obadia
- Service de Neurologie, Fondation Rothschild, 75019, Paris, France
| | - Mickael Obadia
- Service de Neurologie, Fondation Rothschild, 75019, Paris, France
| | - Marion Yger
- AP-HP, Hôpital Saint Antoine, Unité neurovasculaire, 75012, Paris, France
| | - Elena Meseguer
- AP-HP, Service de Neurologie, Hôpital Bichat, 75018, Paris, France
- Laboratory for Vascular Translational Science, INSERM UMRS1148, 75018, Paris, France
| | - Vincent Perlbarg
- Centre de Neuro-Imagerie de Recherche, Institut du Cerveau, CENIR, Paris Brain Institute - ICM, 75013, Paris, France
| | - Romain Valabregue
- Centre de Neuro-Imagerie de Recherche, Institut du Cerveau, CENIR, Paris Brain Institute - ICM, 75013, Paris, France
| | - Serena Magno
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- ICM Infrastructure Stroke Network, STAR Team, Hôpital Pitié-Salpêtrière, 75013, Paris, France
| | - Pavel Lindberg
- Inserm U894, Université Paris Descartes, 75013, Paris, France
| | - Sabine Meunier
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
| | - Jean-Charles Lamy
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
- Centre de Neuro-Imagerie de Recherche, Institut du Cerveau, CENIR, Paris Brain Institute - ICM, 75013, Paris, France
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di Hou M, Santoro V, Biondi A, Shergill SS, Premoli I. A systematic review of TMS and neurophysiological biometrics in patients with schizophrenia. J Psychiatry Neurosci 2021; 46:E675-E701. [PMID: 34933940 PMCID: PMC8695525 DOI: 10.1503/jpn.210006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 08/06/2021] [Accepted: 09/06/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation can be combined with electromyography (TMS-EMG) and electroencephalography (TMS-EEG) to evaluate the excitatory and inhibitory functions of the cerebral cortex in a standardized manner. It has been postulated that schizophrenia is a disorder of functional neural connectivity underpinned by a relative imbalance of excitation and inhibition. The aim of this review was to provide a comprehensive overview of TMS-EMG and TMS-EEG research in schizophrenia, focused on excitation or inhibition, connectivity, motor cortical plasticity and the effect of antipsychotic medications, symptom severity and illness duration on TMS-EMG and TMS-EEG indices. METHODS We searched PsycINFO, Embase and Medline, from database inception to April 2020, for studies that included TMS outcomes in patients with schizophrenia. We used the following combination of search terms: transcranial magnetic stimulation OR tms AND interneurons OR glutamic acid OR gamma aminobutyric acid OR neural inhibition OR pyramidal neurons OR excita* OR inhibit* OR GABA* OR glutam* OR E-I balance OR excitation-inhibition balance AND schizoaffective disorder* OR Schizophrenia OR schizophreni*. RESULTS TMS-EMG and TMS-EEG measurements revealed deficits in excitation or inhibition, functional connectivity and motor cortical plasticity in patients with schizophrenia. Increased duration of the cortical silent period (a TMS-EMG marker of γ-aminobutyric acid B receptor activity) with clozapine was a relatively consistent finding. LIMITATIONS Most of the studies used patients with chronic schizophrenia and medicated patients, employed cross-sectional group comparisons and had small sample sizes. CONCLUSION TMS-EMG and TMS-EEG offer an opportunity to develop a novel and improved understanding of the physiologic processes that underlie schizophrenia and to assess the therapeutic effect of antipsychotic medications. In the future, these techniques may also help predict disease progression and further our understanding of the excitatory/inhibitory balance and its implications for mechanisms that underlie treatment-resistant schizophrenia.
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Affiliation(s)
- Meng di Hou
- From the Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Hou, Shergill); the Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK (Santoro, Biondi, Premoli); and the Kent and Medway Medical School, Canterbury, UK (Shergill)
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Louth EL, Jørgensen RL, Korshoej AR, Sørensen JCH, Capogna M. Dopaminergic Neuromodulation of Spike Timing Dependent Plasticity in Mature Adult Rodent and Human Cortical Neurons. Front Cell Neurosci 2021; 15:668980. [PMID: 33967700 PMCID: PMC8102156 DOI: 10.3389/fncel.2021.668980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 03/29/2021] [Indexed: 11/29/2022] Open
Abstract
Synapses in the cerebral cortex constantly change and this dynamic property regulated by the action of neuromodulators such as dopamine (DA), is essential for reward learning and memory. DA modulates spike-timing-dependent plasticity (STDP), a cellular model of learning and memory, in juvenile rodent cortical neurons. However, it is unknown whether this neuromodulation also occurs at excitatory synapses of cortical neurons in mature adult mice or in humans. Cortical layer V pyramidal neurons were recorded with whole cell patch clamp electrophysiology and an extracellular stimulating electrode was used to induce STDP. DA was either bath-applied or optogenetically released in slices from mice. Classical STDP induction protocols triggered non-hebbian excitatory synaptic depression in the mouse or no plasticity at human cortical synapses. DA reverted long term synaptic depression to baseline in mouse via dopamine 2 type receptors or elicited long term synaptic potentiation in human cortical synapses. Furthermore, when DA was applied during an STDP protocol it depressed presynaptic inhibition in the mouse but not in the human cortex. Thus, DA modulates excitatory synaptic plasticity differently in human vs. mouse cortex. The data strengthens the importance of DA in gating cognition in humans, and may inform on therapeutic interventions to recover brain function from diseases.
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Affiliation(s)
- Emma Louise Louth
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark
| | | | | | | | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark.,Center for Proteins in Memory-PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
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Guerra A, Rocchi L, Grego A, Berardi F, Luisi C, Ferreri F. Contribution of TMS and TMS-EEG to the Understanding of Mechanisms Underlying Physiological Brain Aging. Brain Sci 2021; 11:405. [PMID: 33810206 PMCID: PMC8004753 DOI: 10.3390/brainsci11030405] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
In the human brain, aging is characterized by progressive neuronal loss, leading to disruption of synapses and to a degree of failure in neurotransmission. However, there is increasing evidence to support the notion that the aged brain has a remarkable ability to reorganize itself, with the aim of preserving its physiological activity. It is important to develop objective markers able to characterize the biological processes underlying brain aging in the intact human, and to distinguish them from brain degeneration associated with many neurological diseases. Transcranial magnetic stimulation (TMS), coupled with electromyography or electroencephalography (EEG), is particularly suited to this aim, due to the functional nature of the information provided, and thanks to the ease with which it can be integrated with behavioral manipulation. In this review, we aimed to provide up to date information about the role of TMS and TMS-EEG in the investigation of brain aging. In particular, we focused on data about cortical excitability, connectivity and plasticity, obtained by using readouts such as motor evoked potentials and transcranial evoked potentials. Overall, findings in the literature support an important potential contribution of TMS to the understanding of the mechanisms underlying normal brain aging. Further studies are needed to expand the current body of information and to assess the applicability of TMS findings in the clinical setting.
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Affiliation(s)
| | - Lorenzo Rocchi
- Department of Clinical and Movements Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
- Department of Medical Sciences and Public Health, University of Cagliari, 09124 Cagliari, Italy
| | - Alberto Grego
- Department of Neuroscience, University of Padua, 35122 Padua, Italy; (A.G.); (F.B.); (C.L.)
| | - Francesca Berardi
- Department of Neuroscience, University of Padua, 35122 Padua, Italy; (A.G.); (F.B.); (C.L.)
| | - Concetta Luisi
- Department of Neuroscience, University of Padua, 35122 Padua, Italy; (A.G.); (F.B.); (C.L.)
| | - Florinda Ferreri
- Department of Neuroscience, University of Padua, 35122 Padua, Italy; (A.G.); (F.B.); (C.L.)
- Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, 70210 Kuopio, Finland
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Human Theta Burst Stimulation Combined with Subsequent Electroacupuncture Increases Corticospinal Excitability. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2020:8824530. [PMID: 33424994 PMCID: PMC7773446 DOI: 10.1155/2020/8824530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/15/2020] [Accepted: 12/10/2020] [Indexed: 12/28/2022]
Abstract
Objective Intermittent theta burst stimulation (iTBS) is a widely used noninvasive brain stimulation for the facilitation of corticospinal excitability (CSE). Previous studies have shown that acupuncture applied to acupoints associated with motor function in healthy people can reduce the amplitude of the motor-evoked potentials (MEPs), which reflects the inhibition of CSE. In our work, we wanted to test whether the combination of iTBS and electroacupuncture (EA) would have different effects on CSE in humans. Methods A single-blind sham-controlled crossover design study was conducted on 20 healthy subjects. Subjects received 20 minutes' sham or real EA stimulation immediately after sham or real iTBS. MEPs, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), cortical silent period (CSP), and central motor conduction time (CMCT) were recorded before each trial, and immediately, 20 minutes, and 40 minutes after the end of stimulation. Results In the sham iTBS group, EA produced a reduction in MEPs amplitude, lasting approximately 40 minutes, while in the real iTBS group, EA significantly increased MEPs amplitude beyond 40 minutes after the end of stimulation. In sham EA group, the recorded MEPs amplitude showed no significant trend over time compared to baseline. Among all experiments, there were no significant changes in SICI, ICF, CSP, CMCT, etc. Conclusion These data indicate that immediate application of EA after iTBS significantly increased corticospinal excitability. This trial was registered in the Chinese Clinical Trial Registry (registration no. ChiCTR1900025348).
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Milosevic M, Marquez-Chin C, Masani K, Hirata M, Nomura T, Popovic MR, Nakazawa K. Why brain-controlled neuroprosthetics matter: mechanisms underlying electrical stimulation of muscles and nerves in rehabilitation. Biomed Eng Online 2020; 19:81. [PMID: 33148270 PMCID: PMC7641791 DOI: 10.1186/s12938-020-00824-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 10/10/2020] [Indexed: 12/11/2022] Open
Abstract
Delivering short trains of electric pulses to the muscles and nerves can elicit action potentials resulting in muscle contractions. When the stimulations are sequenced to generate functional movements, such as grasping or walking, the application is referred to as functional electrical stimulation (FES). Implications of the motor and sensory recruitment of muscles using FES go beyond simple contraction of muscles. Evidence suggests that FES can induce short- and long-term neurophysiological changes in the central nervous system by varying the stimulation parameters and delivery methods. By taking advantage of this, FES has been used to restore voluntary movement in individuals with neurological injuries with a technique called FES therapy (FEST). However, long-lasting cortical re-organization (neuroplasticity) depends on the ability to synchronize the descending (voluntary) commands and the successful execution of the intended task using a FES. Brain-computer interface (BCI) technologies offer a way to synchronize cortical commands and movements generated by FES, which can be advantageous for inducing neuroplasticity. Therefore, the aim of this review paper is to discuss the neurophysiological mechanisms of electrical stimulation of muscles and nerves and how BCI-controlled FES can be used in rehabilitation to improve motor function.
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Affiliation(s)
- Matija Milosevic
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan.
| | - Cesar Marquez-Chin
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 520 Sutherland Drive, Toronto, ON, M4G 3V9, Canada
- CRANIA, University Health Network & University of Toronto, 550 University Avenue, Toronto, ON, M5G 2A2, Canada
| | - Kei Masani
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 520 Sutherland Drive, Toronto, ON, M4G 3V9, Canada
- CRANIA, University Health Network & University of Toronto, 550 University Avenue, Toronto, ON, M5G 2A2, Canada
| | - Masayuki Hirata
- Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taishin Nomura
- Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531, Japan
| | - Milos R Popovic
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada
- KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 520 Sutherland Drive, Toronto, ON, M4G 3V9, Canada
- CRANIA, University Health Network & University of Toronto, 550 University Avenue, Toronto, ON, M5G 2A2, Canada
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
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12
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A Bayesian approach to analysing cortico-cortical associative stimulation induced increases in the excitability of corticospinal projections in humans. Exp Brain Res 2020; 239:21-30. [PMID: 33097986 PMCID: PMC7884589 DOI: 10.1007/s00221-020-05943-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/03/2020] [Indexed: 11/05/2022]
Abstract
Repeated pairing of transcranial magnetic stimulation (TMS) over left and right primary motor cortex (M1), at intensities sufficient to generate descending volleys, produces sustained increases in corticospinal excitability. In other paired associative stimulation (PAS) protocols, in which peripheral afferent stimulation is the first element, changes in corticospinal excitability achieved when the second stimulus consists of brief bursts of transcranial alternating current stimulation (tACS), are comparable to those obtained if TMS is used instead (McNickle and Carson 2015). The present aim was to determine whether associative effects are induced when the first stimulus of a cortico-cortical pair is tACS, or alternatively subthreshold TMS. Bursts of tACS (500 ms; 140 Hz; 1 mA) were associated (180 stimulus pairs) with single magnetic stimuli (120% resting motor threshold rMT) delivered over the opposite (left) M1. The tACS ended 6 ms prior to the TMS. In a separate condition, TMS (55% rMT) was delivered to right M1 6 ms before (120% rMT) TMS was applied over left M1. In a sham condition, TMS (120% rMT) was delivered to left M1 only. The limitations of null hypothesis significance testing are well documented. We therefore employed Bayes factors to assess evidence in support of experimental hypotheses—defined precisely in terms of predicted effect sizes, that these two novel variants of PAS increase corticospinal excitability. Although both interventions induced sustained (~ 20–30 min) increases in corticospinal excitability, the evidence in support of the experimental hypotheses (over specified alternatives) was generally greater for the paired TMS-TMS than the tACS-TMS conditions.
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13
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Huang Y, Chen JC, Tsai CH, Lu MK. Convergent Associative Motor Cortical Plasticity Induced by Conditional Somatosensory and Motor Reaction Afferents. Front Hum Neurosci 2020; 14:576171. [PMID: 33192405 PMCID: PMC7609873 DOI: 10.3389/fnhum.2020.576171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022] Open
Abstract
Objective: Associative motor cortical plasticity can be non-invasively induced by paired median nerve electric stimulation and transcranial magnetic stimulation (TMS) of the primary motor cortex (M1). This study investigates whether a simultaneous motor reaction of the other hand advances the associative plasticity in M1. Methods: Twenty-four right-handed subjects received conventional paired associative stimulation (PAS) and PAS with simultaneous motor reaction (PASmr) with at least a 1-week interval. The PASmr protocol additionally included left abductor pollicis brevis muscle movement responding to a digital sound. The motor reaction time was individually measured. The M1 excitability was examined by the motor evoked potential (MEP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) before and after the PAS protocols. Results: The conventional PAS protocol significantly facilitated MEP and suppressed SICI. A negative correlation between the reaction time and the MEP change, and a positive correlation between the reaction time and the ICF change were found in the PASmr protocol. By subgrouping analysis, we further found significant facilitation of MEP and a reduction of ICF in the subjects with fast reaction times but not in those with slow reaction times. Conclusion: Synchronized motor reaction ipsilateral to the stimulated M1 induces associative M1 motor plasticity through the spike-timing dependent principle. MEP and ICF change could represent this kind of plasticity. The current findings provide a novel insight into designing rehabilitation programs concerning motor function.
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Affiliation(s)
- Yi Huang
- Graduate Institute of Biomedical Sciences, College of Medicine, China Medical University, Taichung, Taiwan
| | - Jui-Cheng Chen
- Department of Neurology, China Medical University Hospital, Taichung, Taiwan.,Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan.,School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Chon-Haw Tsai
- Department of Neurology, China Medical University Hospital, Taichung, Taiwan.,Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan.,School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Ming-Kuei Lu
- Graduate Institute of Biomedical Sciences, College of Medicine, China Medical University, Taichung, Taiwan.,Department of Neurology, China Medical University Hospital, Taichung, Taiwan.,Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan.,Ph.D. Program for Translational Medicine, College of Medicine, China Medical University, Taichung, Taiwan
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14
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Kariminezhad S, Karhu J, Säisänen L, Reijonen J, Könönen M, Julkunen P. Brain Response Induced with Paired Associative Stimulation Is Related to Repetition Suppression of Motor Evoked Potential. Brain Sci 2020; 10:brainsci10100674. [PMID: 32993079 PMCID: PMC7600030 DOI: 10.3390/brainsci10100674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/11/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
Repetition suppression (RS), i.e., the reduction of neuronal activity upon repetition of an external stimulus, can be demonstrated in the motor system using transcranial magnetic stimulation (TMS). We evaluated the RS in relation to the neuroplastic changes induced by paired associative stimulation (PAS). An RS paradigm, consisting of 20 trains of four identical suprathreshold TMS pulses 1 s apart, was assessed for motor-evoked potentials (MEPs) in 16 healthy subjects, before and following (at 0, 10, and 20 min) a common PAS protocol. For analysis, we divided RS into two components: (1) the ratio of the second MEP amplitude to the first one in RS trains, i.e., the “dynamic” component, and (2) the mean of the second to fourth MEP amplitudes, i.e., the “stable” component. Following PAS, five subjects showed change in the dynamic RS component. However, nearly all the individuals (n = 14) exhibited change in the stable component (p < 0.05). The stable component was similar between subjects showing increased MEPs and those showing decreased MEPs at this level (p = 0.254). The results suggest the tendency of the brain towards a stable state, probably free from the ongoing dynamics, following PAS.
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Affiliation(s)
- Shohreh Kariminezhad
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland; (J.R.); (P.J.)
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (M.K.)
- Correspondence:
| | | | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (M.K.)
| | - Jusa Reijonen
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland; (J.R.); (P.J.)
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (M.K.)
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (M.K.)
- Department of Clinical Radiology, Kuopio University Hospital, 70029 Kuopio, Finland
| | - Petro Julkunen
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland; (J.R.); (P.J.)
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (M.K.)
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15
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Lee K, Park TIH, Heppner P, Schweder P, Mee EW, Dragunow M, Montgomery JM. Human in vitro systems for examining synaptic function and plasticity in the brain. J Neurophysiol 2020; 123:945-965. [PMID: 31995449 DOI: 10.1152/jn.00411.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The human brain shows remarkable complexity in its cellular makeup and function, which are distinct from nonhuman species, signifying the need for human-based research platforms for the study of human cellular neurophysiology and neuropathology. However, the use of adult human brain tissue for research purposes is hampered by technical, methodological, and accessibility challenges. One of the major problems is the limited number of in vitro systems that, in contrast, are readily available from rodent brain tissue. With recent advances in the optimization of protocols for adult human brain preparations, there is a significant opportunity for neuroscientists to validate their findings in human-based systems. This review addresses the methodological aspects, advantages, and disadvantages of human neuron in vitro systems, focusing on the unique properties of human neurons and synapses in neocortical microcircuits. These in vitro models provide the incomparable advantage of being a direct representation of the neurons that have formed part of the human brain until the point of recording, which cannot be replicated by animal models nor human stem-cell systems. Important distinct cellular mechanisms are observed in human neurons that may underlie the higher order cognitive abilities of the human brain. The use of human brain tissue in neuroscience research also raises important ethical, diversity, and control tissue limitations that need to be considered. Undoubtedly however, these human neuron systems provide critical information to increase the potential of translation of treatments from the laboratory to the clinic in a way animal models are failing to provide.
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Affiliation(s)
- Kevin Lee
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, New Zealand
| | - Thomas I-H Park
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Pharmacology, University of Auckland, Auckland, New Zealand
| | - Peter Heppner
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Patrick Schweder
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Edward W Mee
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Neurosurgery, Auckland City Hospital, Auckland, New Zealand
| | - Michael Dragunow
- Centre for Brain Research, University of Auckland, New Zealand.,Department of Pharmacology, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand.,Centre for Brain Research, University of Auckland, New Zealand
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16
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Sato D, Yamashiro K, Yamazaki Y, Ikarashi K, Onishi H, Baba Y, Maruyama A. Priming Effects of Water Immersion on Paired Associative Stimulation-Induced Neural Plasticity in the Primary Motor Cortex. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 17:ijerph17010215. [PMID: 31892253 PMCID: PMC6982345 DOI: 10.3390/ijerph17010215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/21/2019] [Accepted: 12/23/2019] [Indexed: 11/16/2022]
Abstract
We aimed to verify whether indirect-wave (I-wave) recruitment and cortical inhibition can regulate or predict the plastic response to paired associative stimulation with an inter-stimulus interval of 25 ms (PAS25), and also whether water immersion (WI) can facilitate the subsequent PAS25-induced plasticity. To address the first question, we applied transcranial magnetic stimulation (TMS) to the M1 hand area, while alternating the direction of the induced current between posterior-to-anterior and anterior-to-posterior to activate two independent synaptic inputs to the corticospinal neurons. Moreover, we used a paired stimulation paradigm to evaluate the short-latency afferent inhibition (SAI) and short-interval intracortical inhibition (SICI). To address the second question, we examined the motor evoked potential (MEP) amplitudes before and after PAS25, with and without WI, and used the SAI, SICI, and MEP recruitment curves to determine the mechanism underlying priming by WI on PAS25. We demonstrated that SAI, with an inter-stimulus interval of 25 ms, might serve as a predictor of the response to PAS25, whereas I-wave recruitment evaluated by the MEP latency difference was not predictive of the PAS25 response, and found that 15 min WI prior to PAS25 facilitated long-term potentiation (LTP)-like plasticity due to a homeostatic increase in cholinergic activity.
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Affiliation(s)
- Daisuke Sato
- Department of Health and Sports, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (K.Y.); (Y.B.)
- Institute for Human Movement and Medical Science, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (Y.Y.); (K.I.); (H.O.)
- Correspondence:
| | - Koya Yamashiro
- Department of Health and Sports, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (K.Y.); (Y.B.)
- Institute for Human Movement and Medical Science, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (Y.Y.); (K.I.); (H.O.)
| | - Yudai Yamazaki
- Institute for Human Movement and Medical Science, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (Y.Y.); (K.I.); (H.O.)
- Graduate School, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan
| | - Koyuki Ikarashi
- Institute for Human Movement and Medical Science, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (Y.Y.); (K.I.); (H.O.)
- Graduate School, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan
| | - Hideaki Onishi
- Institute for Human Movement and Medical Science, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (Y.Y.); (K.I.); (H.O.)
| | - Yasuhiro Baba
- Department of Health and Sports, Niigata University of Health and Welfare, Shimamicho 1398, Kita-ku, Niigata City, Niigata 950-3198, Japan; (K.Y.); (Y.B.)
| | - Atsuo Maruyama
- Department of Rehabilitation Medicine, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima City, Kagoshima 890-8520, Japan;
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17
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Tang X, Huang P, Li Y, Lan J, Yang Z, Xu M, Yi W, Lu L, Wang L, Xu N. Age-Related Changes in the Plasticity of Neural Networks Assessed by Transcranial Magnetic Stimulation With Electromyography: A Systematic Review and Meta-Analysis. Front Cell Neurosci 2019; 13:469. [PMID: 31708744 PMCID: PMC6822534 DOI: 10.3389/fncel.2019.00469] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/01/2019] [Indexed: 01/03/2023] Open
Abstract
Objective: The excitability of cerebral cortical cells, neural pathway, and neural networks, as well as their plasticity, are key to our exploration of age-related changes in brain structure and function. The combination of transcranial magnetic stimulation (TMS) with electromyography (EMG) can be applied to the primary motor cortex; it activates the underlying neural group and passes through the corticospinal pathway, which can be quantified using EMG. This meta-analysis aimed to analyze changes in cortical excitability and plasticity in healthy elderly individuals vs. young individuals through TMS-EMG. Methods: The Cochrane Library, Medline, and EMBASE databases were searched to identify eligible trials published from database inception to June 3, 2019. The Cochrane Risk of Bias Tool and improved Jadad scale were used to assess the methodological quality. A meta-analysis of the comparative effects was conducted using the Review Manager 5.3 software and Stata 14.0 software. Results: The pooled results revealed that the resting motor threshold values in the elderly group were markedly higher than those reported in the young group (mean difference [MD]: −2.35; 95% confidence interval [CI]: −3.69 to −1.02]; p < (0.00001). The motor evoked potential amplitude significantly reduced in the elderly group vs. the young group (MD: 0.18; 95% CI: 0.09–0.27; p < 0.0001). Moreover, there was significantly longer motor evoked potential latency in the elderly group (MD: −1.07; 95% CI: −1.77 to −0.37]; p =(0.003). There was no significant difference observed in the active motor threshold between the elderly and young groups (MD: −1.52; 95% CI: −3.47 to −0.42]; p =(0.13). Meanwhile, only two studies reported the absence of adverse events. Conclusion: We found that the excitability of the cerebral cortex declined in elderly individuals vs. young individuals. The findings of the present analysis should be considered with caution owing to the methodological limitations in the included trials. Additional high-quality studies are warranted to validate our findings.
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Affiliation(s)
- Xiaorong Tang
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Peidong Huang
- Acupuncture and Massage Rehabilitation Institute, Yunnan University of Chinese Medicine, Kunming, China
| | - Yitong Li
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Juanchao Lan
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhonghua Yang
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Mindong Xu
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wei Yi
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Liming Lu
- Clinical Research Center, South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lin Wang
- Clinical Research Center, South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Nenggui Xu
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
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18
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Silverstein J, Cortes M, Tsagaris KZ, Climent A, Gerber LM, Oromendia C, Fonzetti P, Ratan RR, Kitago T, Iacoboni M, Wu A, Dobkin B, Edwards DJ. Paired Associative Stimulation as a Tool to Assess Plasticity Enhancers in Chronic Stroke. Front Neurosci 2019; 13:792. [PMID: 31427918 PMCID: PMC6687765 DOI: 10.3389/fnins.2019.00792] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 07/15/2019] [Indexed: 01/08/2023] Open
Abstract
Background and Purpose The potential for adaptive plasticity in the post-stroke brain is difficult to estimate, as is the demonstration of central nervous system (CNS) target engagement of drugs that show promise in facilitating stroke recovery. We set out to determine if paired associative stimulation (PAS) can be used (a) as an assay of CNS plasticity in patients with chronic stroke, and (b) to demonstrate CNS engagement by memantine, a drug which has potential plasticity-modulating effects for use in motor recovery following stroke. Methods We examined the effect of PAS in fourteen participants with chronic hemiparetic stroke at five time-points in a within-subjects repeated measures design study: baseline off-drug, and following a week of orally administered memantine at doses of 5, 10, 15, and 20 mg, comprising a total of seventy sessions. Each week, MEP amplitude pre and post-PAS was assessed in the contralesional hemisphere as a marker of enhanced or diminished plasticity. Strength and dexterity were recorded each week to monitor motor-specific clinical status across the study period. Results We found that MEP amplitude was significantly larger after PAS in baseline sessions off-drug, and responsiveness to PAS in these sessions was associated with increased clinical severity. There was no observed increase in MEP amplitude after PAS with memantine at any dose. Motor threshold (MT), strength, and dexterity remained unchanged during the study. Conclusion Paired associative stimulation successfully induced corticospinal excitability enhancement in chronic stroke subjects at the group level. However, this response did not occur in all participants, and was associated with increased clinical severity. This could be an important way to stratify patients for future PAS-drug studies. PAS was suppressed by memantine at all doses, regardless of responsiveness to PAS off-drug, indicating CNS engagement.
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Affiliation(s)
- Joshua Silverstein
- Human Motor Recovery Laboratory, Burke Neurological Institute, White Plains, NY, United States
| | - Mar Cortes
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Katherine Zoe Tsagaris
- Human Motor Recovery Laboratory, Burke Neurological Institute, White Plains, NY, United States
| | - Alejandra Climent
- Sant Joan de Deu Hospital, Department of Neurology, University of Barcelona, Barcelona, Spain
| | - Linda M Gerber
- Department of Healthcare Policy and Research, Weill Cornell Medical College, New York, NY, United States
| | - Clara Oromendia
- Department of Healthcare Policy and Research, Weill Cornell Medical College, New York, NY, United States
| | - Pasquale Fonzetti
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States.,Memory Evaluation and Treatment Service, Burke Rehabilitation Hospital, White Plains, NY, United States
| | - Rajiv R Ratan
- Department of Neurology, Weill Cornell Medical College, New York, NY, United States.,Burke Neurological Institute, White Plains, NY, United States.,Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, United States
| | - Tomoko Kitago
- Human Motor Recovery Laboratory, Burke Neurological Institute, White Plains, NY, United States.,Department of Neurology, Weill Cornell Medical College, New York, NY, United States
| | - Marco Iacoboni
- Department of Psychiatry and Biobehavioral Sciences, UCLA Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA, United States.,Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - Allan Wu
- Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bruce Dobkin
- Department of Neurology, Geffen School of Medicine, Reed Neurologic Research Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - Dylan J Edwards
- Moss Rehabilitation Research Institute, Elkins Park, PA, United States.,School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
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19
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Murray LM, Knikou M. Repeated cathodal transspinal pulse and direct current stimulation modulate cortical and corticospinal excitability differently in healthy humans. Exp Brain Res 2019; 237:1841-1852. [DOI: 10.1007/s00221-019-05559-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
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20
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Lavender AP, Obata H, Kawashima N, Nakazawa K. Effect of Paired Associative Stimulation on Corticomotor Excitability in Chronic Smokers. Brain Sci 2019; 9:brainsci9030062. [PMID: 30875969 PMCID: PMC6468379 DOI: 10.3390/brainsci9030062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/08/2019] [Accepted: 03/12/2019] [Indexed: 01/22/2023] Open
Abstract
Chronic smoking has been shown to have deleterious effects on brain function and is an important risk factor for ischemic stroke. Reduced cortical excitability has been shown among chronic smokers compared with non-smokers to have a long-term effect and so far no study has assessed the effect of smoking on short-term motor learning. Paired associative stimulation (PAS) is a commonly used method for inducing changes in excitability of the motor cortex (M1) in a way that simulates short-term motor learning. This study employed PAS to investigate the effect of chronic cigarette smoking on plasticity of M1. Stimulator output required to elicit a motor-evoked potential (MEP) of approximately 1 mV was similar between the groups prior to PAS. MEP response to single pulse stimuli increased in the control group and remained above baseline level for at least 30 min after the intervention, but not in the smokers who showed no significant increase in MEP size. The silent period was similar between groups at all time points of the experiment. This study suggests that chronic smoking may have a negative effect on the response to PAS and infers that chronic smoking may have a deleterious effect on the adaptability of M1.
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Affiliation(s)
- Andrew P Lavender
- School of Physiotherapy and Exercise Science, Curtin University, Bentley WA 6102, Australia.
| | - Hiroki Obata
- Department of Humanities and Social Sciences, Institute of Liberal Arts, Kyushu Institute of Technology, Fukuoka 804-8550, Japan.
| | - Noritaka Kawashima
- Department of Rehabilitation of Movement Functions, Research Institute, National Rehabilitation Centre for Persons with Disabilities Tokorozawa, Saitama 359-0042, Japan.
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 113-8654, Japan.
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21
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Huang Y, Chen JC, Chen CM, Tsai CH, Lu MK. Paired Associative Electroacupuncture and Transcranial Magnetic Stimulation in Humans. Front Hum Neurosci 2019; 13:49. [PMID: 30809140 PMCID: PMC6379477 DOI: 10.3389/fnhum.2019.00049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/29/2019] [Indexed: 02/03/2023] Open
Abstract
Pairing transcutaneous electric nerve stimulation (TENS) and transcranial magnetic stimulation (TMS) with specific stimulus-intervals induces associative motor plasticity at the primary motor cortex (M1). Electroacupuncture (EA) is an established medical technique in the eastern countries. This study investigates whether EA paired with TMS induces distinct M1 motor plasticity. Fifteen healthy, right-handed subjects (aged 23.6 ± 2.0 years, eight women) were studied. Two-hundred and twenty-five pairs of TMS of the left M1 preceded by right EA at acupoint “Neiguan” [Pericardium 6 (PC6), located 2 decimeters proximal from the wrist wrinkle] were respectively applied with the interstimulus interval (ISI) of individual somatosensory evoked potential (SSEP) N20 latency plus 2 ms (N20+2) and minus 5 ms (N20-5) with at least 1-week interval. The paired stimulation was delivered at a rate of 0.25 Hz. Sham TMS with a sham coil was adopted to examine the low-frequency EA influence on M1 in eleven subjects. M1 excitability was assessed by motor-evoked potential (MEP) recruitment curve with five TMS intensity levels, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF) and cerebellar inhibition (CBI) at the abductor pollicis brevis (APB) muscle of the right hand before and after the EA-M1 paired associative stimulation (PAS). In addition, median nerve SSEPs and H-reflex were respectively measured to monitor somatosensory and spinal excitability. The MEP showed significantly facilitated after the sham EA-M1 PAS while tested with 80% of the TMS intensity producing on average 1 mV amplitude (i.e., MEP1 mV) in the resting APB muscle. It was also facilitated while tested with 90% MEP1 mV irrespective of the stimulation conditions. The SSEP showed a higher amplitude from the real EA-M1 PAS compared to that from the sham EA-M1 PAS. No significant change was found on SICI, ICF, CBI and H-reflex. Findings suggest that repetitive low frequency EA paired with real TMS did not induce spike-timing dependent motor plasticity but EA paired with sham TMS induced specific M1 excitability change. Complex sensory afferents with dispersed time locked to the sensorimotor cortical area could hamper instead of enhancing the induction of the spike-timing dependent plasticity (STDP) in M1.
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Affiliation(s)
- Yi Huang
- Graduate Institute of Biomedical Sciences, Medical College, China Medical University, Taichung, Taiwan
| | - Jui-Cheng Chen
- Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan.,School of Medicine, Medical College, China Medical University, Taichung, Taiwan
| | - Chun-Ming Chen
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Chon-Haw Tsai
- Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan.,School of Medicine, Medical College, China Medical University, Taichung, Taiwan
| | - Ming-Kuei Lu
- Graduate Institute of Biomedical Sciences, Medical College, China Medical University, Taichung, Taiwan.,Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan
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22
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Terranova C, Rizzo V, Cacciola A, Chillemi G, Calamuneri A, Milardi D, Quartarone A. Is There a Future for Non-invasive Brain Stimulation as a Therapeutic Tool? Front Neurol 2019; 9:1146. [PMID: 30733704 PMCID: PMC6353822 DOI: 10.3389/fneur.2018.01146] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 12/11/2018] [Indexed: 01/11/2023] Open
Abstract
Several techniques and protocols of non-invasive transcranial brain stimulation (NIBS), including transcranial magnetic and electrical stimuli, have been developed in the past decades. These techniques can induce long lasting changes in cortical excitability by promoting synaptic plasticity and thus may represent a therapeutic option in neuropsychiatric disorders. On the other hand, despite these techniques have become popular, the fragility and variability of the after effects are the major challenges that non-invasive transcranial brain stimulation currentlyfaces. Several factors may account for such a variability such as biological variations, measurement reproducibility, and the neuronal state of the stimulated area. One possible strategy, to reduce this variability is to monitor the neuronal state in real time using EEG and trigger TMS pulses only at pre-defined state. In addition, another strategy under study is to use the spaced application of multiple NIBS protocols within a session to improve the reliability and extend the duration of NIBS effects. Further studies, although time consuming, are required for improving the so far limited effect sizes of NIBS protocols for treatment of neurological or psychiatric disorders.
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Affiliation(s)
- Carmen Terranova
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Vincenzo Rizzo
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Alberto Cacciola
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | | | | | | | - Angelo Quartarone
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
- IRCCS Centro Neurolesi ‘Bonino Pulejo’, Messina, Italy
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23
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Carson RG, Rankin ML. Shaping the Effects of Associative Brain Stimulation by Contractions of the Opposite Limb. Front Psychol 2018; 9:2249. [PMID: 30510533 PMCID: PMC6252341 DOI: 10.3389/fpsyg.2018.02249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/29/2018] [Indexed: 12/22/2022] Open
Abstract
There has been an explosion of interest in methods that may promote neural plasticity by indirectly stimulating tissue in damaged brains using transient magnetic fields or weak electrical currents. A major limitation of these approaches is that the induced variations in brain activity tend to be diffuse. Thus far it has proved extremely difficult to target pathways from the brain to specific muscles. This is a particular challenge for applications in rehabilitation. Stroke survivors often exhibit abnormal patterns of muscle activation, including diminished specificity and high levels of co-contraction. For the clinical relevance of brain stimulation to be enhanced, it is desirable that the effects can be restricted to pathways controlling muscles that are the specific targets of movement therapy. We have demonstrated previously that increases in the excitability of corticospinal projections to forearm muscles generated by paired associative stimulation (PAS), are modulated by contractions ipsilateral to the site of the cortical stimulus. The current aim was to determine whether in chronic stroke survivors, simultaneous contractions performed by the non-paretic limb increase the muscle specificity of changes in the excitability of projections to the impaired limb induced by PAS. Ten chronic stroke survivors, 13 age-equivalent and 27 younger healthy controls, completed two separate sessions/conditions. In one (PAS+CONT), isometric wrist flexion contractions of the non-impaired limb were made simultaneously with PAS. In the other (PAS), associative stimulation only was applied. In all groups, PAS alone gave rise to large increases in the excitability of projections to a wrist extensor muscle (extensor carpi radialis – ECR) that was not the target of stimulation. In marked contrast, for the stroke survivors, following combined PAS and flexion contractions of the non-impaired limb, there was no corresponding elevation in the excitability of corticospinal projections to the ECR of the paretic limb. A similar effect was present for the healthy young adults, but not expressed clearly for the age-equivalent controls. The implications of these findings with respect to the clinical deployment of non-invasive brain stimulation in movement rehabilitation are discussed.
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Affiliation(s)
- Richard G Carson
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin, Dublin, Ireland.,School of Psychology, Queen's University Belfast, Belfast, United Kingdom
| | - Michelle L Rankin
- School of Psychology, Queen's University Belfast, Belfast, United Kingdom
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24
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Diana M, Raij T, Melis M, Nummenmaa A, Leggio L, Bonci A. Rehabilitating the addicted brain with transcranial magnetic stimulation. Nat Rev Neurosci 2017; 18:685-693. [PMID: 28951609 DOI: 10.1038/nrn.2017.113] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Substance use disorders (SUDs) are one of the leading causes of morbidity and mortality worldwide. In spite of considerable advances in understanding the neural underpinnings of SUDs, therapeutic options remain limited. Recent studies have highlighted the potential of transcranial magnetic stimulation (TMS) as an innovative, safe and cost-effective treatment for some SUDs. Repetitive TMS (rTMS) influences neural activity in the short and long term by mechanisms involving neuroplasticity both locally, under the stimulating coil, and at the network level, throughout the brain. The long-term neurophysiological changes induced by rTMS have the potential to affect behaviours relating to drug craving, intake and relapse. Here, we review TMS mechanisms and evidence that rTMS is opening new avenues in addiction treatments.
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Affiliation(s)
- Marco Diana
- 'G. Minardi' Laboratory for Cognitive Neuroscience, Department of Chemistry and Pharmacy, University of Sassari, 07100 Sassari, Italy
| | - Tommi Raij
- Shirley Ryan AbilityLab, Center for Brain Stimulation, the Department of Physical Medicine and Rehabilitation and the Department of Neurobiology, Northwestern University, Chicago, Illinois 60611, USA
| | - Miriam Melis
- Department of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, 09042 Monserrato, Italy
| | - Aapo Nummenmaa
- Massachusetts General Hospital (MGH)/Massachusetts Institute of Technology (MIT)/Harvard Medical School (HMS) Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Boston, Massachusetts 02129, USA
| | - Lorenzo Leggio
- Section on Clinical Psychoneuroendocrinology and Neuropsychopharmacology, US National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research (NIAAA DICBR) and US National Institute on Drug Abuse Intramural Research Program (NIDA IRP), NIH (National Institutes of Health), Bethesda, Maryland 20892, USA; and at the Center for Alcohol and Addiction Studies, Brown University, Providence, Rhode Island 02912, USA
| | - Antonello Bonci
- US National Institute on Drug Abuse Intramural Research Program (NIDA IRP); and at the Departments of Neuroscience and Psychiatry, Johns Hopkins University, Baltimore, Maryland 21224, USA
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25
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Nishijima H, Ueno T, Funamizu Y, Ueno S, Tomiyama M. Levodopa treatment and dendritic spine pathology. Mov Disord 2017; 33:877-888. [PMID: 28880414 PMCID: PMC6667906 DOI: 10.1002/mds.27172] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/13/2017] [Accepted: 08/14/2017] [Indexed: 12/20/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder associated with the progressive loss of nigrostriatal dopaminergic neurons. Levodopa is the most effective treatment for the motor symptoms of PD. However, chronic oral levodopa treatment can lead to various motor and nonmotor complications because of nonphysiological pulsatile dopaminergic stimulation in the brain. Examinations of autopsy cases with PD have revealed a decreased number of dendritic spines of striatal neurons. Animal models of PD have revealed altered density and morphology of dendritic spines of neurons in various brain regions after dopaminergic denervation or dopaminergic denervation plus levodopa treatment, indicating altered synaptic transmission. Recent studies using rodent models have reported dendritic spine head enlargement in the caudate‐putamen, nucleus accumbens, primary motor cortex, and prefrontal cortex in cases where chronic levodopa treatment following dopaminergic denervation induced dyskinesia‐like abnormal involuntary movement. Hypertrophy of spines results from insertion of alpha‐amino‐2,3‐dihydro‐5‐methyl‐3‐oxo‐4‐isoxazolepropanoic acid receptors into the postsynaptic membrane. Such spine enlargement indicates hypersensitivity of the synapse to excitatory inputs and is compatible with a lack of depotentiation, which is an electrophysiological hallmark of levodopa‐induced dyskinesia found in the corticostriatal synapses of dyskinetic animals and the motor cortex of dyskinetic PD patients. This synaptic plasticity may be one of the mechanisms underlying the priming of levodopa‐induced complications such as levodopa‐induced dyskinesia and dopamine dysregulation syndrome. Drugs that could potentially prevent spine enlargement, such as calcium channel blockers, N‐methyl‐D‐aspartate receptor antagonists, alpha‐amino‐2,3‐dihydro‐5‐methyl‐3‐oxo‐4‐isoxazolepropanoic acid receptor antagonists, and metabotropic glutamate receptor antagonists, are candidates for treatment of levodopa‐induced complications in PD. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Haruo Nishijima
- Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan.,Department of Neurophysiology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Tatsuya Ueno
- Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan.,Department of Neurophysiology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Yukihisa Funamizu
- Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan
| | - Shinya Ueno
- Department of Neurophysiology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Masahiko Tomiyama
- Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan.,Department of Neurophysiology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
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26
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Opie GM, Vosnakis E, Ridding MC, Ziemann U, Semmler JG. WITHDRAWN: Priming theta burst stimulation enhances motor cortex plasticity in young but not old adults. Brain Stimul 2016:S1935-861X(16)30311-4. [PMID: 27888026 DOI: 10.1016/j.brs.2016.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/16/2016] [Indexed: 10/20/2022] Open
Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - Eleni Vosnakis
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - Michael C Ridding
- Robinson Research Institute, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - Ulf Ziemann
- Department of Neurology & Stroke, Hertie-Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia.
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27
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Lu MK, Chen CM, Duann JR, Ziemann U, Chen JC, Chiou SM, Tsai CH. Investigation of Motor Cortical Plasticity and Corticospinal Tract Diffusion Tensor Imaging in Patients with Parkinsons Disease and Essential Tremor. PLoS One 2016; 11:e0162265. [PMID: 27603204 PMCID: PMC5014415 DOI: 10.1371/journal.pone.0162265] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 08/21/2016] [Indexed: 01/29/2023] Open
Abstract
Parkinson's disease (PD) and essential tremor (ET) are characterized with motor dysfunctions. Motor circuit dysfunctions can be complementarily investigated by paired associative stimulation (PAS)-induced long-term potentiation (LTP)-like plasticity and diffusion tensor imaging (DTI) of the corticospinal tract (CST). Three groups of twelve subjects with moderate severity PD, ET with intention tremor and healthy controls (HC) were studied. The primary motor cortex (M1) excitability, measured by motor evoked potential (MEP) amplitude and by short-interval and long-interval intracortical inhibition (SICI and LICI) was compared between the three groups before and after PAS. The DTI measures of fractional anisotropy (FA) and mean diffusivity (MD) were acquired. PAS effects and DTI data were simultaneously examined between groups. PAS increased MEP amplitude in HC but not in PD and ET. SICI and LICI were significantly reduced after PAS irrespective of groups. No significant differences of the mean FA and MD were found between groups. There was no significant correlation between the PAS effects and the DTI measures. Findings suggest that both PD and ET with intention tremor have impairment of the associative LTP-like corticospinal excitability change in M1. The microstructure of the CST is not relevant to the deficiency of M1 associative plasticity in PD and ET.
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Affiliation(s)
- Ming-Kuei Lu
- Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, Medical College, China Medical University, Taichung, Taiwan
- Graduate Institute of Neural and Cognitive Sciences, Medical College, China Medical University, Taichung, Taiwan
| | - Chun-Ming Chen
- Graduate Institute of Neural and Cognitive Sciences, Medical College, China Medical University, Taichung, Taiwan
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Jeng-Ren Duann
- Institute of Cognitive Neuroscience, National Central University, Zhongli, Taiwan
- Institute for Neural Computation, University of California San Diego, La Jolla, California, United States of America
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, Tübingen, Germany
| | - Jui-Cheng Chen
- Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, Medical College, China Medical University, Taichung, Taiwan
- Graduate Institute of Neural and Cognitive Sciences, Medical College, China Medical University, Taichung, Taiwan
| | - Shang-Ming Chiou
- School of Medicine, Medical College, China Medical University, Taichung, Taiwan
- Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan
| | - Chon-Haw Tsai
- Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, Medical College, China Medical University, Taichung, Taiwan
- Graduate Institute of Neural and Cognitive Sciences, Medical College, China Medical University, Taichung, Taiwan
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28
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Moscatelli F, Messina G, Valenzano A, Petito A, Triggiani AI, Messina A, Monda V, Viggiano A, De Luca V, Capranica L, Monda M, Cibelli G. Differences in corticospinal system activity and reaction response between karate athletes and non-athletes. Neurol Sci 2016; 37:1947-1953. [PMID: 27544220 DOI: 10.1007/s10072-016-2693-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/15/2016] [Indexed: 01/06/2023]
Abstract
The aim of this study was to verify the hypothesis that transcranial magnetic stimulation (TMS) parameters over the hand region of the motor cortex, such as resting motor threshold (rMT) and motor evoked potential (MEP) latency, predict the behavioural performance of karate athletes in the response time (RT) test. Twenty-five male karate athletes (24.9 ± 4.9 years) and 25 matched non-athletes (26.2 ± 4.5 years) were recruited. Using TMS, we investigated cortico-spinal system excitability. Compared with controls, the athletes showed faster RT (p < 0.001), lower rMT (p < 0.01), shorter MEP latency (p < 0.01), and higher MEP amplitude (p < 0.01); moreover, there was a significant positive linear correlation between RT and rMT (p < 0.001), between RT and MEP latency (p < 0.0001), and a negative correlation between RT and MEP amplitude (p < 0.001). The practice of competitive sports affects both the central and peripheral nervous system. Subjects that showed higher cortical excitability showed also higher velocity, at which the neural signal is propagated from the motor cortex to the muscle and consequently better RT. The lower rMT and the shorter MEP latency observed in athletes support the effects of training in determining specific brain organizations to meet specific sport challenges.
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Affiliation(s)
- Fiorenzo Moscatelli
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
- Department of Motor, Human and Health Science, University of Rome, "Foro Italico", Rome, Italy
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy.
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Second University of Naples, Naples, Italy.
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Annamaria Petito
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | | | - Antonietta Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Second University of Naples, Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Second University of Naples, Naples, Italy
| | - Andrea Viggiano
- Department of Medicine and Surgery, University of Salerno, via Allende snc, Baronissi, SA, Italy
| | - Vincenzo De Luca
- Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Laura Capranica
- Department of Motor, Human and Health Science, University of Rome, "Foro Italico", Rome, Italy
| | - Marcellino Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Second University of Naples, Naples, Italy
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
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29
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Weise D, Mann J, Rumpf JJ, Hallermann S, Classen J. Differential Regulation of Human Paired Associative Stimulation-Induced and Theta-Burst Stimulation-Induced Plasticity by L-type and T-type Ca2+Channels. Cereb Cortex 2016; 27:4010-4021. [DOI: 10.1093/cercor/bhw212] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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30
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Dixon L, Ibrahim MM, Santora D, Knikou M. Paired associative transspinal and transcortical stimulation produces plasticity in human cortical and spinal neuronal circuits. J Neurophysiol 2016; 116:904-16. [PMID: 27281748 DOI: 10.1152/jn.00259.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/02/2016] [Indexed: 01/17/2023] Open
Abstract
Anatomical, physiological, and functional connectivity exists between the neurons of the primary motor cortex (M1) and spinal cord. Paired associative stimulation (PAS) produces enduring changes in M1, based on the Hebbian principle of associative plasticity. The present study aimed to establish neurophysiological changes in human cortical and spinal neuronal circuits by pairing noninvasive transspinal stimulation with transcortical stimulation via transcranial magnetic stimulation (TMS). We delivered paired transspinal and transcortical stimulation for 40 min at precise interstimulus intervals, with TMS being delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Transspinal-transcortical PAS markedly decreased intracortical inhibition, increased intracortical facilitation and M1 excitability with concomitant decreases of motor threshold, and reduced the soleus Hoffmann's reflex (H-reflex) low frequency-mediated homosynaptic depression. Transcortical-transspinal PAS did not affect intracortical circuits, decreased M1 excitability, and reduced the soleus H-reflex-paired stimulation pulses' mediated postactivation depression. Both protocols affected the excitation threshold of group Ia afferents and motor axons. These findings clearly indicate that the pairing of transspinal with transcortical stimulation produces cortical and spinal excitability changes based on the timing interval and functional network interactions between the two associated inputs. This new PAS paradigm may constitute a significant neuromodulation method with physiological impact, because it can be used to alter concomitantly excitability of intracortical circuits, corticospinal neurons, and spinal inhibition in humans.
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Affiliation(s)
- Luke Dixon
- Department of Physical Therapy, College of Staten Island, New York, New York
| | - Mohamed M Ibrahim
- Department of Physical Therapy, College of Staten Island, New York, New York
| | - Danielle Santora
- Department of Physical Therapy, College of Staten Island, New York, New York
| | - Maria Knikou
- Graduate Center, City University of New York, New York, New York; and Department of Physical Therapy, College of Staten Island, New York, New York
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31
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Promoting Motor Cortical Plasticity with Acute Aerobic Exercise: A Role for Cerebellar Circuits. Neural Plast 2016; 2016:6797928. [PMID: 27127659 PMCID: PMC4834415 DOI: 10.1155/2016/6797928] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 02/26/2016] [Accepted: 03/13/2016] [Indexed: 01/27/2023] Open
Abstract
Acute aerobic exercise facilitated long-term potentiation-like plasticity in the human primary motor cortex (M1). Here, we investigated the effect of acute aerobic exercise on cerebellar circuits, and their potential contribution to altered M1 plasticity in healthy individuals (age: 24.8 ± 4.1 years). In Experiment 1, acute aerobic exercise reduced cerebellar inhibition (CBI) (n = 10, p = 0.01), elicited by dual-coil paired-pulse transcranial magnetic stimulation. In Experiment 2, we evaluated the facilitatory effects of aerobic exercise on responses to paired associative stimulation, delivered with a 25 ms (PAS25) or 21 ms (PAS21) interstimulus interval (n = 16 per group). Increased M1 excitability evoked by PAS25, but not PAS21, relies on trans-cerebellar sensory pathways. The magnitude of the aerobic exercise effect on PAS response was not significantly different between PAS protocols (interaction effect: p = 0.30); however, planned comparisons indicated that, relative to a period of rest, acute aerobic exercise enhanced the excitatory response to PAS25 (p = 0.02), but not PAS21 (p = 0.30). Thus, the results of these planned comparisons indirectly provide modest evidence that modulation of cerebellar circuits may contribute to exercise-induced increases in M1 plasticity. The findings have implications for developing aerobic exercise strategies to "prime" M1 plasticity for enhanced motor skill learning in applied settings.
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32
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Kamke MR, Nydam AS, Sale MV, Mattingley JB. Associative plasticity in the human motor cortex is enhanced by concurrently targeting separate muscle representations with excitatory and inhibitory protocols. J Neurophysiol 2016; 115:2191-8. [PMID: 26864761 DOI: 10.1152/jn.00794.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/09/2016] [Indexed: 12/11/2022] Open
Abstract
Paired associative stimulation (PAS) induces changes in the excitability of human sensorimotor cortex that outlast the procedure. PAS typically involves repeatedly pairing stimulation of a peripheral nerve that innervates an intrinsic hand muscle with transcranial magnetic stimulation over the representation of that muscle in the primary motor cortex. Depending on the timing of the stimuli (interstimulus interval of 25 or 10 ms), PAS leads to either an increase (PAS25) or a decrease (PAS10) in excitability. Both protocols, however, have been associated with an increase in excitability of nearby muscle representations not specifically targeted by PAS. Based on these spillover effects, we hypothesized that an additive, excitability-enhancing effect of PAS25 applied to one muscle representation may be produced by simultaneously applying PAS25 or PAS10 to a nearby representation. In different experiments prototypical PAS25 targeting the left thumb representation [abductor pollicis brevis (APB)] was combined with either PAS25 or PAS10 applied to the left little finger representation [abductor digiti minimi (ADM)] or, in a control experiment, with PAS10 also targeting the APB. In an additional control experiment PAS10 targeted both representations. The plasticity effects were quantified by measuring the amplitude of motor evoked potentials (MEPs) recorded before and after PAS. As expected, prototypical PAS25 was associated with an increase in MEP amplitude in the APB muscle. This effect was enhanced when PAS also targeted the ADM representation but only when a different interstimulus timing (PAS10) was used. These results suggest that PAS-induced plasticity is modified by concurrently targeting separate motor cortical representations with excitatory and inhibitory protocols.
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Affiliation(s)
- Marc R Kamke
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; and
| | - Abbey S Nydam
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; and
| | - Martin V Sale
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; and
| | - Jason B Mattingley
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; and School of Psychology, The University of Queensland, Brisbane, Queensland, Australia
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33
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Fuhl A, Müller-Dahlhaus F, Lücke C, Toennes SW, Ziemann U. Low Doses of Ethanol Enhance LTD-like Plasticity in Human Motor Cortex. Neuropsychopharmacology 2015; 40:2969-80. [PMID: 26038159 PMCID: PMC4864632 DOI: 10.1038/npp.2015.151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/25/2015] [Accepted: 05/25/2015] [Indexed: 12/26/2022]
Abstract
Humans liberally use ethanol for its facilitating effects on social interactions but its effects on central nervous system function remain underexplored. We have recently described that very low doses of ethanol abolish long-term potentiation (LTP)-like plasticity in human cortex, most likely through enhancement of tonic inhibition [Lücke et al, 2014, Neuropsychopharmacology 39:1508-18]. Here, we studied the effects of low-dose ethanol on long-term depression (LTD)-like plasticity. LTD-like plasticity was induced in human motor cortex by paired associative transcranial magnetic stimulation (PASLTD), and measured as decreases of motor evoked potential input-output curve (IO-curve). In addition, sedation was measured by decreases in saccade peak velocity (SPV). Ethanol in two low doses (EtOH<10mM, EtOH<20mM) was compared to single oral doses of alprazolam (APZ, 1mg) a classical benzodiazepine, and zolpidem (ZLP, 10 mg), a non-benzodiazepine hypnotic, in a double-blinded randomized placebo-controlled crossover design in ten healthy human subjects. EtOH<10mM and EtOH<20mM but not APZ or ZLP enhanced the PASLTD-induced LTD-like plasticity, while APZ and ZLP but not EtOH<10mM or EtOH<20mM decreased SPV. Non-sedating low doses of ethanol, easily reached during social drinking, enhance LTD-like plasticity in human cortex. This effect is most likely explained by the activation of extrasynaptic α4-subunit containing gamma-aminobutyric type A receptors by low-dose EtOH, resulting in increased tonic inhibition. Findings may stimulate cellular research on the role of tonic inhibition in regulating excitability and plasticity of cortical neuronal networks.
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Affiliation(s)
- Anna Fuhl
- Department of Neurology, Goethe-University, Frankfurt am Main, Germany
| | - Florian Müller-Dahlhaus
- Department of Neurology, Goethe-University, Frankfurt am Main, Germany,Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany
| | - Caroline Lücke
- Department of Neurology, Goethe-University, Frankfurt am Main, Germany,Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe-University, Frankfurt am Main, Germany
| | - Stefan W Toennes
- Department of Forensic Toxicology, Goethe-University, Frankfurt am Main, Germany
| | - Ulf Ziemann
- Department of Neurology, Goethe-University, Frankfurt am Main, Germany,Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany,Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University Tübingen, Hoppe-Seyler-Str. 3, Tübingen, D-72076, Germany, Tel: +49 7071 2982049, Fax: +49 7071 295260, E-mail:
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Augmenting LTP-Like Plasticity in Human Motor Cortex by Spaced Paired Associative Stimulation. PLoS One 2015; 10:e0131020. [PMID: 26110758 PMCID: PMC4482149 DOI: 10.1371/journal.pone.0131020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/26/2015] [Indexed: 11/29/2022] Open
Abstract
Paired associative stimulation (PASLTP) of the human primary motor cortex (M1) can induce LTP-like plasticity by increasing corticospinal excitability beyond the stimulation period. Previous studies showed that two consecutive PASLTP protocols interact by homeostatic metaplasticity, but animal experiments provided evidence that LTP can be augmented by repeated stimulation protocols spaced by ~30min. Here we tested in twelve healthy selected PASLTP responders the possibility that LTP-like plasticity can be augmented in the human M1 by systematically varying the interval between two consecutive PASLTP protocols. The first PASLTP protocol (PAS1) induced strong LTP-like plasticity lasting for 30-60min. The effect of a second identical PASLTP protocol (PAS2) critically depended on the time between PAS1 and PAS2. At 10min, PAS2 prolonged the PAS1-induced LTP-like plasticity. At 30min, PAS2 augmented the LTP-like plasticity induced by PAS1, by increasing both magnitude and duration. At 60min and 180min, PAS2 had no effect on corticospinal excitability. The cumulative LTP-like plasticity after PAS1 and PAS2 at 30min exceeded significantly the effect of PAS1 alone, and the cumulative PAS1 and PAS2 effects at 60min and 180min. In summary, consecutive PASLTP protocols interact in human M1 in a time-dependent manner. If spaced by 30min, two consecutive PASLTP sessions can augment LTP-like plasticity in human M1. Findings may inspire further research on optimized therapeutic applications of non-invasive brain stimulation in neurological and psychiatric diseases.
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Takeuchi N, Izumi SI. Combinations of stroke neurorehabilitation to facilitate motor recovery: perspectives on Hebbian plasticity and homeostatic metaplasticity. Front Hum Neurosci 2015; 9:349. [PMID: 26157374 PMCID: PMC4477170 DOI: 10.3389/fnhum.2015.00349] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 05/31/2015] [Indexed: 12/12/2022] Open
Abstract
Motor recovery after stroke involves developing new neural connections, acquiring new functions, and compensating for impairments. These processes are related to neural plasticity. Various novel stroke rehabilitation techniques based on basic science and clinical studies of neural plasticity have been developed to aid motor recovery. Current research aims to determine whether using combinations of these techniques can synergistically improve motor recovery. When different stroke neurorehabilitation therapies are combined, the timing of each therapeutic program must be considered to enable optimal neural plasticity. Synchronizing stroke rehabilitation with voluntary neural and/or muscle activity can lead to motor recovery by targeting Hebbian plasticity. This reinforces the neural connections between paretic muscles and the residual motor area. Homeostatic metaplasticity, which stabilizes the activity of neurons and neural circuits, can either augment or reduce the synergic effect depending on the timing of combination therapy and types of neurorehabilitation that are used. Moreover, the possibility that the threshold and degree of induced plasticity can be altered after stroke should be noted. This review focuses on the mechanisms underlying combinations of neurorehabilitation approaches and their future clinical applications. We suggest therapeutic approaches for cortical reorganization and maximal functional gain in patients with stroke, based on the processes of Hebbian plasticity and homeostatic metaplasticity. Few of the possible combinations of stroke neurorehabilitation have been tested experimentally; therefore, further studies are required to determine the appropriate combination for motor recovery.
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Affiliation(s)
- Naoyuki Takeuchi
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine Sendai, Japan
| | - Shin-Ichi Izumi
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine Sendai, Japan
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Tsang P, Bailey AZ, Nelson AJ. Rapid-rate paired associative stimulation over the primary somatosensory cortex. PLoS One 2015; 10:e0120731. [PMID: 25799422 PMCID: PMC4370473 DOI: 10.1371/journal.pone.0120731] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/26/2015] [Indexed: 11/24/2022] Open
Abstract
Rapid-rate paired associative stimulation (rPAS) involves repeat pairing of peripheral nerve stimulation and Transcranial magnetic stimulation (TMS) pulses at a 5 Hz frequency. RPAS over primary motor cortex (M1) operates with spike-timing dependent plasticity such that increases in corticospinal excitability occur when the nerve and TMS pulse temporally coincide in cortex. The present study investigates the effects of rPAS over primary somatosensory cortex (SI) which has not been performed to date. In a series of experiments, rPAS was delivered over SI and M1 at varying timing intervals between the nerve and TMS pulse based on the latency of the N20 somatosensory evoked potential (SEP) component within each participant (intervals for SI-rPAS: N20, N20-2.5 ms, N20 + 2.5 ms, intervals for M1-rPAS: N20, N20+5 ms). Changes in SI physiology were measured via SEPs (N20, P25, N20-P25) and SEP paired-pulse inhibition, and changes in M1 physiology were measured with motor evoked potentials and short-latency afferent inhibition. Measures were obtained before rPAS and at 5, 25 and 45 minutes following stimulation. Results indicate that paired-pulse inhibition and short-latency afferent inhibition were reduced only when the SI-rPAS nerve-TMS timing interval was set to N20-2.5 ms. SI-rPAS over SI also led to remote effects on motor physiology over a wider range of nerve-TMS intervals (N20-2.5 ms – N20+2.5 ms) during which motor evoked potentials were increased. M1-rPAS increased motor evoked potentials and reduced short-latency afferent inhibition as previously reported. These data provide evidence that, similar to M1, rPAS over SI is spike-timing dependent and is capable of exerting changes in SI and M1 physiology.
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Affiliation(s)
- Philemon Tsang
- Department of Kinesiology, McMaster University, Hamilton, Canada
| | - Aaron Z. Bailey
- Department of Kinesiology, McMaster University, Hamilton, Canada
| | - Aimee J. Nelson
- Department of Kinesiology, McMaster University, Hamilton, Canada
- * E-mail:
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McNickle E, Carson RG. Paired associative transcranial alternating current stimulation increases the excitability of corticospinal projections in humans. J Physiol 2015; 593:1649-66. [PMID: 25504575 DOI: 10.1113/jphysiol.2014.280453] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 12/01/2014] [Indexed: 11/08/2022] Open
Abstract
Many types of non-invasive brain stimulation alter corticospinal excitability (CSE). Paired associative stimulation (PAS) has attracted particular attention as its effects ostensibly adhere to Hebbian principles of neural plasticity. In prototypical form, a single electrical stimulus is directed to a peripheral nerve in close temporal contiguity with transcranial magnetic stimulation delivered to the contralateral primary motor cortex (M1). Repeated pairing of the two discrete stimulus events (i.e. association) over an extended period either increases or decreases the excitability of corticospinal projections from M1, contingent on the interstimulus interval. We studied a novel form of associative stimulation, consisting of brief trains of peripheral afferent stimulation paired with short bursts of high frequency (≥80 Hz) transcranial alternating current stimulation (tACS) over contralateral M1. Elevations in the excitability of corticospinal projections to the forearm were observed for a range of tACS frequency (80, 140 and 250 Hz), current (1, 2 and 3 mA) and duration (500 and 1000 ms) parameters. The effects were at least as reliable as those brought about by PAS or transcranial direct current stimulation. When paired with tACS, muscle tendon vibration also induced elevations of CSE. No such changes were brought about by the tACS or peripheral afferent stimulation alone. In demonstrating that associative effects are expressed when the timing of the peripheral and cortical events is not precisely circumscribed, these findings suggest that multiple cellular pathways may contribute to a long term potentiation-type response. Their relative contributions will differ depending on the nature of the induction protocol that is used.
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Affiliation(s)
- Emmet McNickle
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin, Ireland; School of Psychology, Queen's University Belfast, Northern Ireland, UK
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Grimaldi G, Argyropoulos GP, Bastian A, Cortes M, Davis NJ, Edwards DJ, Ferrucci R, Fregni F, Galea JM, Hamada M, Manto M, Miall RC, Morales-Quezada L, Pope PA, Priori A, Rothwell J, Tomlinson SP, Celnik P. Cerebellar Transcranial Direct Current Stimulation (ctDCS): A Novel Approach to Understanding Cerebellar Function in Health and Disease. Neuroscientist 2014; 22:83-97. [PMID: 25406224 PMCID: PMC4712385 DOI: 10.1177/1073858414559409] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cerebellum is critical for both motor and cognitive control. Dysfunction of the cerebellum is a component of multiple neurological disorders. In recent years, interventions have been developed that aim to excite or inhibit the activity and function of the human cerebellum. Transcranial direct current stimulation of the cerebellum (ctDCS) promises to be a powerful tool for the modulation of cerebellar excitability. This technique has gained popularity in recent years as it can be used to investigate human cerebellar function, is easily delivered, is well tolerated, and has not shown serious adverse effects. Importantly, the ability of ctDCS to modify behavior makes it an interesting approach with a potential therapeutic role for neurological patients. Through both electrical and non-electrical effects (vascular, metabolic) ctDCS is thought to modify the activity of the cerebellum and alter the output from cerebellar nuclei. Physiological studies have shown a polarity-specific effect on the modulation of cerebellar–motor cortex connectivity, likely via cerebellar–thalamocortical pathways. Modeling studies that have assessed commonly used electrode montages have shown that the ctDCS-generated electric field reaches the human cerebellum with little diffusion to neighboring structures. The posterior and inferior parts of the cerebellum (i.e., lobules VI-VIII) seem particularly susceptible to modulation by ctDCS. Numerous studies have shown to date that ctDCS can modulate motor learning, and affect cognitive and emotional processes. Importantly, this intervention has a good safety profile; similar to when applied over cerebral areas. Thus, investigations have begun exploring ctDCS as a viable intervention for patients with neurological conditions.
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Affiliation(s)
| | - Georgios P Argyropoulos
- Department of Psychology, Brain, Action and Cognition Lab, University of London, Egham, Surrey, UK
| | - Amy Bastian
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mar Cortes
- Burke Medical Research Institute, Departments of Neurology and Neuroscience, Weill Medical College of Cornell University, White Plains, NY, USA
| | | | - Dylan J Edwards
- Burke Medical Research Institute, Departments of Neurology and Neuroscience, Weill Medical College of Cornell University, White Plains, NY, USA
| | - Roberta Ferrucci
- Department of Medical-Surgical Pathophysiology and Transplants, University of Milan, Milan, Italy Clinical Center for Neurotechnology, Neurostimulation and Movement Disorders, Fondazione IRCCS "Ca' Granda" Ospedale Maggiore di Milano, Milan, Italy
| | - Felipe Fregni
- Center of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - Joseph M Galea
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK
| | - Masahi Hamada
- Department of Neurology, The University of Tokyo, Tokyo, Japan
| | - Mario Manto
- Unité d'Etude du Mouvement, ULB-Erasme, Brussels, Belgium
| | - R Chris Miall
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK
| | - Leon Morales-Quezada
- Center of Neuromodulation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - Paul A Pope
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK
| | - Alberto Priori
- Department of Medical-Surgical Pathophysiology and Transplants, University of Milan, Milan, Italy Clinical Center for Neurotechnology, Neurostimulation and Movement Disorders, Fondazione IRCCS "Ca' Granda" Ospedale Maggiore di Milano, Milan, Italy
| | - John Rothwell
- Institute of Neurology, University College London, London, UK
| | | | - Pablo Celnik
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Two distinct interneuron circuits in human motor cortex are linked to different subsets of physiological and behavioral plasticity. J Neurosci 2014; 34:12837-49. [PMID: 25232119 DOI: 10.1523/jneurosci.1960-14.2014] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
How does a single brain region participate in multiple behaviors? Here we argue that two separate interneuron circuits in the primary motor cortex (M1) contribute differently to two varieties of physiological and behavioral plasticity. To test this in human brain noninvasively, we used transcranial magnetic stimulation (TMS) of M1 hand area to activate two independent sets of synaptic inputs to corticospinal neurons by changing the direction of current induced in the brain: posterior-to-anterior current (PA inputs) and anterior-to-posterior current (AP inputs). We demonstrate that excitability changes produced by repetitive activation of AP inputs depend on cerebellar activity and selectively alter model-based motor learning. In contrast, the changes observed with repetitive stimulation of PA inputs are independent of cerebellar activity and specifically modulate model-free motor learning. The findings are highly suggestive that separate circuits in M1 subserve different forms of motor learning.
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40
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Grimaldi G, Argyropoulos GP, Boehringer A, Celnik P, Edwards MJ, Ferrucci R, Galea JM, Groiss SJ, Hiraoka K, Kassavetis P, Lesage E, Manto M, Miall RC, Priori A, Sadnicka A, Ugawa Y, Ziemann U. Non-invasive cerebellar stimulation--a consensus paper. THE CEREBELLUM 2014; 13:121-38. [PMID: 23943521 DOI: 10.1007/s12311-013-0514-7] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The field of neurostimulation of the cerebellum either with transcranial magnetic stimulation (TMS; single pulse or repetitive (rTMS)) or transcranial direct current stimulation (tDCS; anodal or cathodal) is gaining popularity in the scientific community, in particular because these stimulation techniques are non-invasive and provide novel information on cerebellar functions. There is a consensus amongst the panel of experts that both TMS and tDCS can effectively influence cerebellar functions, not only in the motor domain, with effects on visually guided tracking tasks, motor surround inhibition, motor adaptation and learning, but also for the cognitive and affective operations handled by the cerebro-cerebellar circuits. Verbal working memory, semantic associations and predictive language processing are amongst these operations. Both TMS and tDCS modulate the connectivity between the cerebellum and the primary motor cortex, tuning cerebellar excitability. Cerebellar TMS is an effective and valuable method to evaluate the cerebello-thalamo-cortical loop functions and for the study of the pathophysiology of ataxia. In most circumstances, DCS induces a polarity-dependent site-specific modulation of cerebellar activity. Paired associative stimulation of the cerebello-dentato-thalamo-M1 pathway can induce bidirectional long-term spike-timing-dependent plasticity-like changes of corticospinal excitability. However, the panel of experts considers that several important issues still remain unresolved and require further research. In particular, the role of TMS in promoting cerebellar plasticity is not established. Moreover, the exact positioning of electrode stimulation and the duration of the after effects of tDCS remain unclear. Future studies are required to better define how DCS over particular regions of the cerebellum affects individual cerebellar symptoms, given the topographical organization of cerebellar symptoms. The long-term neural consequences of non-invasive cerebellar modulation are also unclear. Although there is an agreement that the clinical applications in cerebellar disorders are likely numerous, it is emphasized that rigorous large-scale clinical trials are missing. Further studies should be encouraged to better clarify the role of using non-invasive neurostimulation techniques over the cerebellum in motor, cognitive and psychiatric rehabilitation strategies.
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Affiliation(s)
- G Grimaldi
- Unité d'Etude du Mouvement, Hôpital Erasme-ULB, 808 Route de Lennik, 1070, Brussels, Belgium,
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Liew SL, Santarnecchi E, Buch ER, Cohen LG. Non-invasive brain stimulation in neurorehabilitation: local and distant effects for motor recovery. Front Hum Neurosci 2014; 8:378. [PMID: 25018714 PMCID: PMC4072967 DOI: 10.3389/fnhum.2014.00378] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 05/14/2014] [Indexed: 01/01/2023] Open
Abstract
Non-invasive brain stimulation (NIBS) may enhance motor recovery after neurological injury through the causal induction of plasticity processes. Neurological injury, such as stroke, often results in serious long-term physical disabilities, and despite intensive therapy, a large majority of brain injury survivors fail to regain full motor function. Emerging research suggests that NIBS techniques, such as transcranial magnetic (TMS) and direct current (tDCS) stimulation, in association with customarily used neurorehabilitative treatments, may enhance motor recovery. This paper provides a general review on TMS and tDCS paradigms, the mechanisms by which they operate and the stimulation techniques used in neurorehabilitation, specifically stroke. TMS and tDCS influence regional neural activity underlying the stimulation location and also distant interconnected network activity throughout the brain. We discuss recent studies that document NIBS effects on global brain activity measured with various neuroimaging techniques, which help to characterize better strategies for more accurate NIBS stimulation. These rapidly growing areas of inquiry may hold potential for improving the effectiveness of NIBS-based interventions for clinical rehabilitation.
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Affiliation(s)
- Sook-Lei Liew
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, NIH Bethesda, MD, USA
| | | | - Ethan R Buch
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, NIH Bethesda, MD, USA ; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of Health Sciences Bethesda, MD, USA
| | - Leonardo G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, NIH Bethesda, MD, USA ; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of Health Sciences Bethesda, MD, USA
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Brandt VC, Niessen E, Ganos C, Kahl U, Bäumer T, Münchau A. Altered synaptic plasticity in Tourette's syndrome and its relationship to motor skill learning. PLoS One 2014; 9:e98417. [PMID: 24878665 PMCID: PMC4039486 DOI: 10.1371/journal.pone.0098417] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 05/02/2014] [Indexed: 11/25/2022] Open
Abstract
Gilles de la Tourette syndrome is a neuropsychiatric disorder characterized by motor and phonic tics that can be considered motor responses to preceding inner urges. It has been shown that Tourette patients have inferior performance in some motor learning tasks and reduced synaptic plasticity induced by transcranial magnetic stimulation. However, it has not been investigated whether altered synaptic plasticity is directly linked to impaired motor skill acquisition in Tourette patients. In this study, cortical plasticity was assessed by measuring motor-evoked potentials before and after paired associative stimulation in 14 Tourette patients (13 male; age 18–39) and 15 healthy controls (12 male; age 18–33). Tic and urge severity were assessed using the Yale Global Tic Severity Scale and the Premonitory Urges for Tics Scale. Motor learning was assessed 45 minutes after inducing synaptic plasticity and 9 months later, using the rotary pursuit task. On average, long-term potentiation-like effects in response to the paired associative stimulation were present in healthy controls but not in patients. In Tourette patients, long-term potentiation-like effects were associated with more and long-term depression-like effects with less severe urges and tics. While motor learning did not differ between patients and healthy controls 45 minutes after inducing synaptic plasticity, the learning curve of the healthy controls started at a significantly higher level than the Tourette patients' 9 months later. Induced synaptic plasticity correlated positively with motor skills in healthy controls 9 months later. The present study confirms previously found long-term improvement in motor performance after paired associative stimulation in healthy controls but not in Tourette patients. Tourette patients did not show long-term potentiation in response to PAS and also showed reduced levels of motor skill consolidation after 9 months compared to healthy controls. Moreover, synaptic plasticity appears to be related to symptom severity.
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Affiliation(s)
- Valerie Cathérine Brandt
- Institute of Neurogenetics, University of Lübeck, Lübeck, Schleswig-Holstein, Germany
- Department of Neurology, University Clinic Hamburg-Eppendorf, Hamburg, Hamburg, Germany
- * E-mail:
| | - Eva Niessen
- Institute of Neuroscience & Medicine, Research Centre Jülich, Jülich, Nordrhein-Westfalen, Germany
| | - Christos Ganos
- Institute of Neurogenetics, University of Lübeck, Lübeck, Schleswig-Holstein, Germany
- Department of Neurology, University Clinic Hamburg-Eppendorf, Hamburg, Hamburg, Germany
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, London, United Kingdom
| | - Ursula Kahl
- Department of Neurology, University Clinic Hamburg-Eppendorf, Hamburg, Hamburg, Germany
| | - Tobias Bäumer
- Institute of Neurogenetics, University of Lübeck, Lübeck, Schleswig-Holstein, Germany
| | - Alexander Münchau
- Institute of Neurogenetics, University of Lübeck, Lübeck, Schleswig-Holstein, Germany
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Deleterious effects of a low amount of ethanol on LTP-like plasticity in human cortex. Neuropsychopharmacology 2014; 39:1508-18. [PMID: 24385131 PMCID: PMC3988555 DOI: 10.1038/npp.2013.350] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 12/28/2013] [Accepted: 12/28/2013] [Indexed: 11/08/2022]
Abstract
Ingesting ethanol (EtOH) at low doses during social drinking is a common human behavior for its facilitating effects on social interactions. However, low-dose EtOH may have also detrimental effects that so far are underexplored. Here we sought to test the effects of low-dose EtOH on long-term potentiation (LTP)-like plasticity in human motor cortex. Previous cellular experiments showed that low-dose EtOH potentiates extrasynaptic GABAAR and reduces NMDAR-mediated currents, processes that would limit the expression of LTP. Paired associative transcranial magnetic stimulation (PASLTP) was employed in nine healthy subjects for induction of LTP-like plasticity, indexed by a long-term increase in motor-evoked potential input-output curves. Synaptic α1-GABAAR function was measured by saccadic peak velocity (SPV). Very low doses of EtOH (resulting in blood concentrations of <5 mM) suppressed LTP-like plasticity but did not affect SPV when compared with a placebo condition. In contrast, 1 mg of alprazolam, a classical benzodiazepine, or 10 mg of zolpidem, a non-benzodiazepine hypnotic, decreased SPV but did not significantly affect LTP-like plasticity when compared with placebo. This double dissociation of low-dose EtOH vs alprazolam/zolpidem effects is best explained by the putatively high affinity of EtOH but not alprazolam/zolpidem to extrasynaptic GABAARs and to NMDARs. Findings suggest that enhancement of extrasynaptic GABAAR-mediated tonic inhibition and/or reduction of NMDAR-mediated neurotransmission by EtOH blocks LTP-like plasticity in human cortex at very low doses that are easily reached during social drinking. Therefore, low-dose EtOH may jeopardize LTP-dependent processes, such as learning and memory formation.
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Visual spatial attention has opposite effects on bidirectional plasticity in the human motor cortex. J Neurosci 2014; 34:1475-80. [PMID: 24453335 DOI: 10.1523/jneurosci.1595-13.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are key mechanisms of synaptic plasticity that are thought to act in concert to shape neural connections. Here we investigated the influence of visual spatial attention on LTP-like and LTD-like plasticity in the human motor cortex. Plasticity was induced using paired associative stimulation (PAS), which involves repeated pairing of peripheral nerve stimulation and transcranial magnetic stimulation to alter functional responses in the thumb area of the primary motor cortex. PAS-induced changes in cortical excitability were assessed using motor-evoked potentials. During plasticity induction, participants directed their attention to one of two visual stimulus streams located adjacent to each hand. When participants attended to visual stimuli located near the left thumb, which was targeted by PAS, LTP-like increases in excitability were significantly enhanced, and LTD-like decreases in excitability reduced, relative to when they attended instead to stimuli located near the right thumb. These differential effects on (bidirectional) LTP-like and LTD-like plasticity suggest that voluntary visual attention can exert an important influence on the functional organization of the motor cortex. Specifically, attention acts to both enhance the strengthening and suppress the weakening of neural connections representing events that fall within the focus of attention.
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45
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Mechanisms underlying the rules for associative plasticity at adult human neocortical synapses. J Neurosci 2013; 33:17197-208. [PMID: 24155324 DOI: 10.1523/jneurosci.3158-13.2013] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The neocortex in our brain stores long-term memories by changing the strength of connections between neurons. To date, the rules and mechanisms that govern activity-induced synaptic changes at human cortical synapses are poorly understood and have not been studied directly at a cellular level. Here, we made whole-cell recordings of human pyramidal neurons in slices of brain tissue resected during neurosurgery to investigate spike timing-dependent synaptic plasticity in the adult human neocortex. We find that human cortical synapses can undergo bidirectional modifications in strength throughout adulthood. Both long-term potentiation and long-term depression of synapses was dependent on postsynaptic NMDA receptors. Interestingly, we find that human cortical synapses can associate presynaptic and postsynaptic events in a wide temporal window, and that rules for synaptic plasticity in human neocortex are reversed compared with what is generally found in the rodent brain. We show this is caused by dendritic L-type voltage-gated Ca2+ channels that are prominently activated during action potential firing. Activation of these channels determines whether human synapses strengthen or weaken. These findings provide a synaptic basis for the timing rules observed in human sensory and motor plasticity in vivo, and offer insights into the physiological role of L-type voltage-gated Ca2+ channels in the human brain.
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Carson RG, Kennedy NC. Modulation of human corticospinal excitability by paired associative stimulation. Front Hum Neurosci 2013; 7:823. [PMID: 24348369 PMCID: PMC3847812 DOI: 10.3389/fnhum.2013.00823] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 11/14/2013] [Indexed: 12/04/2022] Open
Abstract
Paired Associative Stimulation (PAS) has come to prominence as a potential therapeutic intervention for the treatment of brain injury/disease, and as an experimental method with which to investigate Hebbian principles of neural plasticity in humans. Prototypically, a single electrical stimulus is directed to a peripheral nerve in advance of transcranial magnetic stimulation (TMS) delivered to the contralateral primary motor cortex (M1). Repeated pairing of the stimuli (i.e., association) over an extended period may increase or decrease the excitability of corticospinal projections from M1, in manner that depends on the interstimulus interval (ISI). It has been suggested that these effects represent a form of associative long-term potentiation (LTP) and depression (LTD) that bears resemblance to spike-timing dependent plasticity (STDP) as it has been elaborated in animal models. With a large body of empirical evidence having emerged since the cardinal features of PAS were first described, and in light of the variations from the original protocols that have been implemented, it is opportune to consider whether the phenomenology of PAS remains consistent with the characteristic features that were initially disclosed. This assessment necessarily has bearing upon interpretation of the effects of PAS in relation to the specific cellular pathways that are putatively engaged, including those that adhere to the rules of STDP. The balance of evidence suggests that the mechanisms that contribute to the LTP- and LTD-type responses to PAS differ depending on the precise nature of the induction protocol that is used. In addition to emphasizing the requirement for additional explanatory models, in the present analysis we highlight the key features of the PAS phenomenology that require interpretation.
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Affiliation(s)
- Richard G Carson
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin Dublin, Ireland ; School of Psychology, Queen's University Belfast Belfast, UK
| | - Niamh C Kennedy
- School of Psychology, Queen's University Belfast Belfast, UK ; School of Rehabilitation Sciences University of East Anglia Norwich, UK
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Luber B, McClintock SM, Lisanby SH. Applications of transcranial magnetic stimulation and magnetic seizure therapy in the study and treatment of disorders related to cerebral aging. DIALOGUES IN CLINICAL NEUROSCIENCE 2013. [PMID: 23576892 PMCID: PMC3622472 DOI: 10.31887/dcns.2013.15.1/bluber] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Transcranial magnetic stimulation (TMS) can be used to probe cortical function and treat neuropsychiatric illnesses. TMS has demonstrated neuroplastic effects akin to long-term potentiation and long-term depression, and therapeutic applications are in development for post-stroke recovery, Alzheimer's disease, and depression in seniors. Here, we discuss two new directions of TMS research relevant to cerebral aging and cognition. First, we introduce a paradigm for enhancing cognitive reserve, based on our research in sleep deprivation. Second, we discuss the use of magnetic seizure therapy (MST) to spare cognitive functions relative to conventional electroconvulsive therapy, and as a means of providing a more potent antidepressant treatment when subconvulsive TMS has shown modest efficacy in seniors. Whether in the enhancement of cognition as a treatment goal, or in the reduction of amnesia as a side effect, these approaches to the use of TMS and MST merit further exploration regarding their clinical potential.
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Affiliation(s)
- Bruce Luber
- Department of Psychiatry and Behavioral Sciences, Department of Psychology and Neuroscience, Duke University, Durham, NC, USA.
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Weise D, Mann J, Ridding M, Eskandar K, Huss M, Rumpf JJ, Di Lazzaro V, Mazzone P, Ranieri F, Classen J. Microcircuit mechanisms involved in paired associative stimulation-induced depression of corticospinal excitability. J Physiol 2013; 591:4903-20. [PMID: 23858008 DOI: 10.1113/jphysiol.2013.253989] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptic weight changes induced by temporal correlations between the spikes of pre- and postsynaptic neurons are referred to as spike-timing-dependent plasticity (STDP). Transcranial magnetic stimulation (TMS) induces long-lasting effects on corticospinal excitability, if it is repetitively paired with stimulation of afferents from a corresponding contralateral hand region at short intervals (paired associative stimulation, PAS). PAS-induced plasticity has been linked with synaptic STDP. We aimed to investigate which elements of the cortical microcircuitry sustain and govern PAS-induced depression of corticospinal excitability in the target muscle representation (and enhancement of excitability in its functional surround). We show that the time window during which the interaction between both stimulus-induced cortical events leads to immediate post-interventional depression is short (<4.5 ms). The depressant PAS effects at the target representation were completely blocked by applying a subthreshold magnetic pulse 3 ms before the principal TMS pulse, even when the strength of the latter was adjusted to generate a motor-evoked potential of similar amplitude to that with the unconditioned magnetic pulse. Epidural recordings from the cervical cord of a patient showed that under this condition late TMS-evoked I-waves remain suppressed. When the intensity of the TMS component during PAS was lowered - sufficient to allow activation of inhibitory neurons, but insufficient to activate corticospinal neurons - excitability of short-latency intracortical inhibition remained unchanged. PAS-induced facilitation in the functional surround followed the same pattern as the centre-depressant effects. These findings may suggest that excitability-depressant PAS-induced effects are due to weakening of excitatory synapses between upper cortical layer principal neurons, but not those located on the corticospinal neuron, or inhibitory synapses. Inhibitory interneurons involved in short-latency intracortical inhibition are gate-keepers to producing centre-depressant/surround-facilitatory PAS effects. Based on these and earlier findings we propose a model specifying the composition and laminar location of the involved microcircuit of PAS-induced plasticity that may enhance its utility as a model of STDP in humans.
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Affiliation(s)
- David Weise
- J. Classen: University of Leipzig, Department of Neurology, Liebigstr. 20, Leipzig 04103, Germany.
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Conde V, Vollmann H, Taubert M, Sehm B, Cohen LG, Villringer A, Ragert P. Reversed timing-dependent associative plasticity in the human brain through interhemispheric interactions. J Neurophysiol 2013; 109:2260-71. [PMID: 23407353 DOI: 10.1152/jn.01004.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spike timing-dependent plasticity (STDP) has been proposed as one of the key mechanisms underlying learning and memory. Repetitive median nerve stimulation, followed by transcranial magnetic stimulation (TMS) of the contralateral primary motor cortex (M1), defined as paired-associative stimulation (PAS), has been used as an in vivo model of STDP in humans. PAS-induced excitability changes in M1 have been repeatedly shown to be time-dependent in a STDP-like fashion, since synchronous arrival of inputs within M1 induces long-term potentiation-like effects, whereas an asynchronous arrival induces long-term depression (LTD)-like effects. Here, we show that interhemispheric inhibition of the sensorimotor network during PAS, with the peripheral stimulation over the hand ipsilateral to the motor cortex receiving TMS, results in a LTD-like effect, as opposed to the standard STDP-like effect seen for contralateral PAS. Furthermore, we could show that this reversed-associative plasticity critically depends on the timing interval between afferent and cortical stimulation. These results indicate that the outcome of associative stimulation in the human brain depends on functional network interactions (inhibition or facilitation) at a systems level and can either follow standard or reversed STDP-like mechanisms.
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Affiliation(s)
- Virginia Conde
- Max Planck Institute for Human Cognitive and Brain Sciences and Department of Neurology and Clinic for Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany.
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Abstract
Stroke is a leading cause of disability, and the number of stroke survivors continues to rise. Traditional neurorehabilitation strategies aimed at restoring function to weakened limbs provide only modest benefit. New brain stimulation techniques designed to augment traditional neurorehabilitation hold promise for reducing the burden of stroke-related disability. Investigators discovered that repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and epidural cortical stimulation (ECS) can enhance neural plasticity in the motor cortex post-stroke. Improved outcomes may be obtained with activity-dependent stimulation, in which brain stimulation is contingent on neural or muscular activity during normal behavior. We review the evidence for improved motor function in stroke patients treated with rTMS, tDCS, and ECS and discuss the mediating physiological mechanisms. We compare these techniques to activity-dependent stimulation, discuss the advantages of this newer strategy for stroke rehabilitation, and suggest future applications for activity-dependent brain stimulation.
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