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Kishore A, James P, Popa T, Thejaus A, Rajeswari P, Sarma G, Krishnan S, Meunier S. Plastic responsiveness of motor cortex to paired associative stimulation depends on cerebellar input. Clin Neurophysiol 2021; 132:2493-2502. [PMID: 34454278 DOI: 10.1016/j.clinph.2021.06.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 06/06/2021] [Accepted: 06/17/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The extent of plastic responses of motor cortex (M1) to paired associative stimulation (PAS) varies among healthy subjects. Continuous theta-burst stimulation (cTBS) of cerebellum enhances the mean PAS-induced plasticity in groups of healthy subjects. We tested whether the initial status of Responder or Non -Responder to PAS, influenced the effect of cerebellar stimulation on PAS-induced plasticity. METHODS We assessed in 19 young healthy volunteers (8 Responders, 11 Non-Responders to PAS), how cTBS and iTBS (intermittent TBS) applied to the cerebellum before a PAS protocol influenced the plastic responsiveness of M1 to PAS. We tested whether the PAS-induced plastic effects could be depotentiated by a short cTBS protocol applied to M1 shortly after PAS and whether cerebellar stimulation influenced GABA-ergic intracortical inhibition and M1 plasticity in parallel. RESULTS Cerebellar cTBS restored the M1 response to PAS in Non-Responders while cerebellar iTBS turned the potentiating response to PAS to a depressive response in both groups. The depotentiation protocol abolished both responses. CONCLUSION Non-Responder status to PAS is a state of M1 amenable to bidirectional plastic modulation when primed by a change in cerebello-thalamic drive. SIGNIFICANCE The meaning of lack of responsiveness to certain protocols probing plasticity should be reconsidered.
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Affiliation(s)
- Asha Kishore
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India.
| | - Praveen James
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India
| | - Traian Popa
- Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL), 1202 Geneva, Switzerland; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Swiss Federal Institute of Technology (EPFL Valais), Clinique Romande de Réadaptation, 1951 Sion, Switzerland
| | - Arun Thejaus
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India
| | - Parvathy Rajeswari
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India
| | - Gangadhara Sarma
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India
| | - Syam Krishnan
- Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Kerala, India
| | - Sabine Meunier
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, Institut du Cerveau et de la Moelleépinière, ICM, F-75013 Paris, France
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Altered motor cortical plasticity in patients with hepatic encephalopathy: A paired associative stimulation study. Clin Neurophysiol 2021; 132:2332-2341. [PMID: 34454259 DOI: 10.1016/j.clinph.2021.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 06/29/2021] [Accepted: 07/03/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Hepatic encephalopathy (HE) is a potentially reversible brain dysfunction caused by liver failure. Altered synaptic plasticity is supposed to play a major role in the pathophysiology of HE. Here, we used paired associative stimulation with an inter-stimulus interval of 25 ms (PAS25), a transcranial magnetic stimulation (TMS) protocol, to test synaptic plasticity of the motor cortex in patients with manifest HE. METHODS 23 HE-patients and 23 healthy controls were enrolled in the study. Motor evoked potential (MEP) amplitudes were assessed as measure for cortical excitability. Time courses of MEP amplitude changes after the PAS25 intervention were compared between both groups. RESULTS MEP-amplitudes increased after PAS25 in the control group, indicating PAS25-induced synaptic plasticity in healthy controls, as expected. In contrast, MEP-amplitudes within the HE group did not change and were lower than in the control group, indicating no induction of plasticity. CONCLUSIONS Our study revealed reduced synaptic plasticity of the primary motor cortex in HE. SIGNIFICANCE Reduced synaptic plasticity in HE provides a link between pathological changes on the molecular level and early clinical symptoms of the disease. This decrease may be caused by disturbances in the glutamatergic neurotransmission due to the known hyperammonemia in HE patients.
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Opie GM, Liao WY, Semmler JG. Interactions Between Cerebellum and the Intracortical Excitatory Circuits of Motor Cortex: a Mini-Review. CEREBELLUM (LONDON, ENGLAND) 2021; 21:159-166. [PMID: 33978934 DOI: 10.1007/s12311-021-01278-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 05/03/2021] [Indexed: 12/28/2022]
Abstract
Interactions between cerebellum (CB) and primary motor cortex (M1) are critical for effective motor function. Although the associated neurophysiological processes are yet to be fully characterised, a growing body of work using non-invasive brain stimulation (NIBS) techniques has significantly progressed our current understanding. In particular, recent developments with both transcranial magnetic (TMS) and direct current (tDCS) stimulation suggest that CB modulates the activity of local excitatory interneuronal circuits within M1. These circuits are known to be important both physiologically and functionally, and understanding the nature of their connectivity with CB therefore has the potential to provide important insight for NIBS applications. Consequently, this mini-review provides an overview of the emerging literature that has investigated interactions between CB and the intracortical excitatory circuits of M1.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Wei-Yeh Liao
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, 5005, Australia.
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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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Behrangrad S, Zoghi M, Kidgell D, Jaberzadeh S. Does cerebellar non-invasive brain stimulation affect corticospinal excitability in healthy individuals? A systematic review of literature and meta-analysis. Neurosci Lett 2019; 706:128-139. [PMID: 31102706 DOI: 10.1016/j.neulet.2019.05.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/12/2019] [Accepted: 05/14/2019] [Indexed: 10/26/2022]
Abstract
Numerous studies have indicated that non-invasive brain stimulation (NIBS) of the cerebellum could modulate corticospinal excitability (CSE) in young healthy individuals. However, there is no systematic review and meta-analysis that clarifies the effects of cerebellar NIBS on CSE. The aim of this study was to provide a meta-analytic summary of the effects of cerebellar NIBS on CSE. Seven search engines were used to identify any trial evaluating CSE before and after one session of cerebellar NIBS in healthy individuals up to June 2018. Twenty-six studies investigating the corticospinal responses following cerebellar NIBS were included. Meta-analysis was used to pool the findings from included studies. Effects were expressed as mean differences (MD) and the standard deviation (SD). Risk of bias was assessed with the Cochrane tool. Meta-analysis found that paired associative stimulation (PAS) with 2 ms interval, a combination of PAS with 21.5 ms interval and anodal transcranial direct current stimulation, and repetitive transcranial magnetic stimulation with a frequency of < 5 Hz increase CSE (P PAS2 < 0.00001, P PAS21.5 +a-tDCS = 0.02, P rTMS = 0.04). However, continuous theta burst stimulation, a combination of PAS with 25 ms interval and anodal transcranial direct current stimulation, and PAS with a 6 ms interval decreased CSE (P PAS6 < 0.00001, P cTBS < 0.00001, P PAS25 +a-tDCS = 0.003). The results of this review show that cerebellar NIBS techniques are a promising tool for increasing CSE.
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Affiliation(s)
- Shabnam Behrangrad
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, P.O. Box 527, Australia.
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Bundoora, Victoria, Australia
| | - Dawson Kidgell
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, P.O. Box 527, Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, P.O. Box 527, Australia
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The unsolved role of heightened connectivity from the unaffected hemisphere to paretic arm muscles in chronic stroke. Clin Neurophysiol 2019; 130:781-788. [PMID: 30925310 DOI: 10.1016/j.clinph.2019.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 02/06/2019] [Accepted: 02/27/2019] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Ipsilateral connectivity from the non-stroke hemisphere to paretic arm muscles appears to play little role in functional recovery, which instead depends on contralateral connectivity from the stroke hemisphere. Yet the incidence of ipsilateral projections in stroke survivors is often reported to be higher than normal. We tested this directly using a sensitive measure of connectivity to proximal arm muscles. METHOD TMS of the stroke and non-stroke motor cortex evoked responses in pre-activated triceps and deltoid muscles of 17 stroke survivors attending reaching training. Connectivity was defined as a clear MEP or a short-latency silent period in ongoing EMG in ≥ 50% of stimulations. We measured reaching accuracy at baseline, improvement after training and upper limb Fugl-Meyer (F-M) score. RESULTS Incidence of ipsilateral connections to triceps (47%) and deltoid (58%) was high, but unrelated to baseline reaching accuracy and F-M scores. Instead, these were related to contralateral connectivity from the stroke hemisphere. Absolute but not proportional improvement after training was greater in patients with ipsilateral responses. CONCLUSIONS Despite enhanced ipsilateral connectivity, arm function and learning was related most strongly to contralateral pathway integrity from the stroke hemisphere. SIGNIFICANCE Further work is needed to decipher the role of ipsilateral connections.
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Abstract
Transcranial magnetic and electric stimulation of the brain are novel and highly promising techniques currently employed in both research and clinical practice. Improving or rehabilitating brain functions by modulating excitability with these noninvasive tools is an exciting new area in neuroscience. Since the cerebellum is closely connected with the cerebral regions subserving motor, associative, and affective functions, the cerebello-thalamo-cortical pathways are an interesting target for these new techniques. Targeting the cerebellum represents a novel way to modulate the excitability of remote cortical regions and their functions. This review brings together the studies that have applied cerebellar stimulation, magnetic and electric, and presents an overview of the current knowledge and unsolved issues. Some recommendations for future research are implemented as well.
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Suppa A, Quartarone A, Siebner H, Chen R, Di Lazzaro V, Del Giudice P, Paulus W, Rothwell J, Ziemann U, Classen J. The associative brain at work: Evidence from paired associative stimulation studies in humans. Clin Neurophysiol 2017; 128:2140-2164. [DOI: 10.1016/j.clinph.2017.08.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/20/2017] [Accepted: 08/03/2017] [Indexed: 12/25/2022]
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Kačar A, Milanović SD, Filipović SR, Ljubisavljević MR. Changes in cortical excitability during paired associative stimulation in Parkinson's disease patients and healthy subjects. Neurosci Res 2017; 124:51-56. [PMID: 28606723 DOI: 10.1016/j.neures.2017.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Paired associative stimulation (PAS) combines repetitive peripheral nerve stimulation with motor cortex (M1) transcranial magnetic stimulation (TMS), to induce plastic-like changes of cortical excitability. While much attention has been dedicated to post-PAS effects little is known about processes during PAS. We compared the time-course of changes in M1 excitability during standard facilitatory PAS intervention among patients with Parkinson's disease (PD), known to have diminished post-PAS response, and healthy subjects. Compared to baseline pre-PAS MEPs, conditioned MEPs during PAS decreased significantly in both groups. The decrease was significantly larger in healthy subjects than in PD patients, regardless whether patients were drug-naïve or not. Although post-PAS excitability increase was also larger in healthy subjects than in PD patients, there was no significant correlation between the two phenomena, i.e. the extent of MEP decrease during PAS and the extent of the post-PAS excitability increase. The results highlight an apparent physiological paradox that repetitive application of an inhibitory stimulation pattern leads to subsequent prolonged facilitation, thus broadening the understanding of the phenomenology of PAS response. Results also suggest that in PD cortical circuits involved in conveying inhibition during PAS, are impaired at the clinical onset of the disease and are not influenced by subsequent PD treatment.
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Affiliation(s)
- Aleksandra Kačar
- Department of Neurophysiology, Institute for Medical Research, University of Belgrade, Dr Subotica 4, Belgrade, Serbia; Neuroloska Klinika, Klinicki Centar Srbije, Dr. Subotica 6, Belgrade, Serbia.
| | - Sladjan D Milanović
- Department of Neurophysiology, Institute for Medical Research, University of Belgrade, Dr Subotica 4, Belgrade, Serbia.
| | - Saša R Filipović
- Department of Neurophysiology, Institute for Medical Research, University of Belgrade, Dr Subotica 4, Belgrade, Serbia.
| | - Miloš R Ljubisavljević
- Department of Neurophysiology, Institute for Medical Research, University of Belgrade, Dr Subotica 4, Belgrade, Serbia; Department of Physiology, College of Medicine and Health Sciences, Po Box 17666, UAE University, Al Ain, United Arab Emirates.
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Motor cortex plasticity can indicate vulnerability to motor fluctuation and high L-DOPA need in drug-naïve Parkinson's disease. Parkinsonism Relat Disord 2017; 35:55-62. [DOI: 10.1016/j.parkreldis.2016.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 10/02/2016] [Accepted: 12/12/2016] [Indexed: 11/18/2022]
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Tremblay S, Austin D, Hannah R, Rothwell JC. Non-invasive brain stimulation as a tool to study cerebellar-M1 interactions in humans. CEREBELLUM & ATAXIAS 2016; 3:19. [PMID: 27895926 PMCID: PMC5111316 DOI: 10.1186/s40673-016-0057-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/01/2016] [Indexed: 12/29/2022]
Abstract
The recent development of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) has allowed the non-invasive assessment of cerebellar function in humans. Early studies showed that cerebellar activity, as reflected in the excitability of the dentate-thalamo-cortical pathway, can be assessed with paired stimulation of the cerebellum and the primary motor cortex (M1) (cerebellar inhibition of motor cortex, CBI). Following this, many attempts have been made, using techniques such as repetitive TMS and transcranial electrical stimulation (TES), to modulate the activity of the cerebellum and the dentate-thalamo-cortical output, and measure their impact on M1 activity. The present article reviews literature concerned with the impact of non-invasive stimulation of cerebellum on M1 measures of excitability and "plasticity" in both healthy and clinical populations. The main conclusion from the 27 reviewed articles is that the effects of cerebellar "plasticity" protocols on M1 activity are generally inconsistent. Nevertheless, two measurements showed relatively reproducible effects in healthy individuals: reduced response of M1 to sensorimotor "plasticity" (paired-associative stimulation, PAS) and reduced CBI following repetitive TMS and TES. We discuss current challenges, such as the low power of reviewed studies, variability in stimulation parameters employed and lack of understanding of physiological mechanisms underlying CBI.
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Affiliation(s)
- Sara Tremblay
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Duncan Austin
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, WC1N 3BG UK
| | - Ricci Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, WC1N 3BG UK
| | - John C Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, WC1N 3BG UK
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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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Inducing LTD-Like Effect in the Human Motor Cortex with Low Frequency and Very Short Duration Paired Associative Stimulation: An Exploratory Study. Neural Plast 2016; 2016:3920298. [PMID: 26904298 PMCID: PMC4745907 DOI: 10.1155/2016/3920298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/24/2015] [Accepted: 12/29/2015] [Indexed: 01/01/2023] Open
Abstract
Introduction. Paired associative stimulation (PAS) is an established technique to investigate synaptic plasticity in the human motor cortex (M1). Classically, to induce long-term depression- (LTD-) or long-term potentiation-like effects in the human M1, studies have used low frequency and long duration trains of PAS. In the present study, we explored an LTD-like effect using very short duration and low frequency of PAS10 ms protocols in human M1. Methods. Six protocols of low frequency PAS10 ms (ranging from 0.2 Hz to 1 Hz) were investigated with very short durations of 1 and 2 minutes stimulation. Six healthy volunteers were included in each protocol. We obtained motor-evoked potentials from right abductor pollicis brevis muscle before and after applying PAS10 ms up to 30 minutes. After we found PAS10 ms protocol which induced an LTD-like effect, we tested that protocol on additional 5 subjects. Results. One-way repeated-measures ANOVA showed that only the group of 1-minute stimulation of 0.25 Hz induced an LTD-like effect. When adding the additional subjects, the effect remained and lasted for 30 minutes. Conclusion. Low frequency and very short duration of PAS10 ms potentially induced an LTD-like effect in human M1. With further verification, this method might be useful for research relating to synaptic plasticity by reducing the duration of study and minimizing subject discomfort.
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Clark R, Blizzard C, Dickson T. Inhibitory dysfunction in amyotrophic lateral sclerosis: future therapeutic opportunities. Neurodegener Dis Manag 2015; 5:511-25. [DOI: 10.2217/nmt.15.49] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In amyotrophic lateral sclerosis, motor neuron hyperexcitability and inhibitory dysfunction is emerging as a potential causative link in the dysfunction and degeneration of the motoneuronal circuitry that characterizes the disease. Interneurons, as key regulators of excitability, may mediate much of this imbalance, yet we know little about the way in which inhibitory deficits perturb excitability. In this review, we explore inhibitory control of excitability and the potential contribution of altered inhibition to amyotrophic lateral sclerosis disease processes and vulnerabilities, identifying important windows of therapeutic opportunity and potential interventions, specifically targeting inhibitory control at key disease stages.
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Affiliation(s)
- Rosemary Clark
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Catherine Blizzard
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
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Dubbioso R, Pellegrino G, Antenora A, De Michele G, Filla A, Santoro L, Manganelli F. The Effect of Cerebellar Degeneration on Human Sensori-motor Plasticity. Brain Stimul 2015; 8:1144-50. [DOI: 10.1016/j.brs.2015.05.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 04/20/2015] [Accepted: 05/30/2015] [Indexed: 10/23/2022] Open
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Strigaro G, Falletta L, Cerino A, Pizzamiglio C, Tondo G, Varrasi C, Cantello R. Abnormal motor cortex plasticity in juvenile myoclonic epilepsy. Seizure 2015. [DOI: 10.1016/j.seizure.2015.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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17
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Kumpulainen S, Peltonen J, Gruber M, Cresswell A, Peurala S, Linnamo V, Avela J. The effect of paired associative stimulation on fatigue resistance. Neurosci Res 2015; 95:59-65. [PMID: 25659758 DOI: 10.1016/j.neures.2015.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 01/22/2015] [Accepted: 01/29/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Paired associative stimulation (PAS) is a non-invasive stimulation method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscles. However, very few studies have shown an association between changes in motor evoked potentials (MEP) after PAS and behavioral changes in healthy subjects. In the present study we hypothesized that the functional relevance of PAS can be seen during fatiguing exercise, since there is always a central contribution to the development of fatigue. Transcranial magnetic stimulation was applied over the motor cortex to measure changes in the MEPs of the soleus muscle before and after PAS. Furthermore, fatigue resistance was tested during 15s sustained maximal isometric contractions before and after PAS. On average, fatigue resistance did not change after PAS, however the change in excitability correlated significantly with the change in fatigue resistance. DISCUSSION Functionality of PAS intervention was not demonstrated in this study. However, the observed relationship between excitability and fatigue resistance suggests that PAS might have affected central fatigue during short maximal contractions.
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Affiliation(s)
- Susanne Kumpulainen
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland.
| | - Jussi Peltonen
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland
| | - Markus Gruber
- Sensorimotor Performance Lab, Department of Sport Science, University of Konstanz, Germany
| | - Andrew Cresswell
- School of Human Movement Studies, University of Queensland, Australia
| | | | - Vesa Linnamo
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland
| | - Janne Avela
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland
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