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Dharmadasa T, Pavey N, Tu S, Menon P, Huynh W, Mahoney CJ, Timmins HC, Higashihara M, van den Bos M, Shibuya K, Kuwabara S, Grosskreutz J, Kiernan MC, Vucic S. Novel approaches to assessing upper motor neuron dysfunction in motor neuron disease/amyotrophic lateral sclerosis: IFCN handbook chapter. Clin Neurophysiol 2024; 163:68-89. [PMID: 38705104 DOI: 10.1016/j.clinph.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 02/08/2024] [Accepted: 04/14/2024] [Indexed: 05/07/2024]
Abstract
Identifying upper motor neuron (UMN) dysfunction is fundamental to the diagnosis and understanding of disease pathogenesis in motor neuron disease (MND). The clinical assessment of UMN dysfunction may be difficult, particularly in the setting of severe muscle weakness. From a physiological perspective, transcranial magnetic stimulation (TMS) techniques provide objective biomarkers of UMN dysfunction in MND and may also be useful to interrogate cortical and network function. Single, paired- and triple pulse TMS techniques have yielded novel diagnostic and prognostic biomarkers in MND, and have provided important pathogenic insights, particularly pertaining to site of disease onset. Cortical hyperexcitability, as heralded by reduced short interval intracortical inhibition (SICI) and increased short interval intracortical facilitation, has been associated with the onset of lower motor neuron degeneration, along with patterns of disease spread, development of specific clinical features such as the split hand phenomenon, and may provide an indication about the rate of disease progression. Additionally, reduction of SICI has emerged as a potential diagnostic aid in MND. The triple stimulation technique (TST) was shown to enhance the diagnostic utility of conventional TMS measures in detecting UMN dysfunction in MND. Separately, sophisticated brain imaging techniques have uncovered novel biomarkers of neurodegeneration that have bene associated with progression. The present review will discuss the utility of TMS and brain neuroimaging derived biomarkers of UMN dysfunction in MND, focusing on recently developed TMS techniques and advanced neuroimaging modalities that interrogate structural and functional integrity of the corticomotoneuronal system, with an emphasis on pathogenic, diagnostic, and prognostic utility.
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Affiliation(s)
- Thanuja Dharmadasa
- Department of Neurology, The Royal Melbourne Hospital City Campus, Parkville, Victoria, Australia
| | - Nathan Pavey
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - Sicong Tu
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Parvathi Menon
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - William Huynh
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Colin J Mahoney
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Hannah C Timmins
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Mana Higashihara
- Department of Neurology, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
| | - Mehdi van den Bos
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - Kazumoto Shibuya
- Neurology, Chiba University, Graduate School of Medicine, Chiba, Japan
| | - Satoshi Kuwabara
- Neurology, Chiba University, Graduate School of Medicine, Chiba, Japan
| | - Julian Grosskreutz
- Precision Neurology, Excellence Cluster Precision Medicine in Inflammation, University of Lübeck, University Hospital Schleswig-Holstein Campus, Lübeck, Germany
| | - Matthew C Kiernan
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Steve Vucic
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia.
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2
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Vucic S, Stanley Chen KH, Kiernan MC, Hallett M, Benninger DH, Di Lazzaro V, Rossini PM, Benussi A, Berardelli A, Currà A, Krieg SM, Lefaucheur JP, Long Lo Y, Macdonell RA, Massimini M, Rosanova M, Picht T, Stinear CM, Paulus W, Ugawa Y, Ziemann U, Chen R. Clinical diagnostic utility of transcranial magnetic stimulation in neurological disorders. Updated report of an IFCN committee. Clin Neurophysiol 2023; 150:131-175. [PMID: 37068329 PMCID: PMC10192339 DOI: 10.1016/j.clinph.2023.03.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/28/2023] [Accepted: 03/09/2023] [Indexed: 03/31/2023]
Abstract
The review provides a comprehensive update (previous report: Chen R, Cros D, Curra A, Di Lazzaro V, Lefaucheur JP, Magistris MR, et al. The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol 2008;119(3):504-32) on clinical diagnostic utility of transcranial magnetic stimulation (TMS) in neurological diseases. Most TMS measures rely on stimulation of motor cortex and recording of motor evoked potentials. Paired-pulse TMS techniques, incorporating conventional amplitude-based and threshold tracking, have established clinical utility in neurodegenerative, movement, episodic (epilepsy, migraines), chronic pain and functional diseases. Cortical hyperexcitability has emerged as a diagnostic aid in amyotrophic lateral sclerosis. Single-pulse TMS measures are of utility in stroke, and myelopathy even in the absence of radiological changes. Short-latency afferent inhibition, related to central cholinergic transmission, is reduced in Alzheimer's disease. The triple stimulation technique (TST) may enhance diagnostic utility of conventional TMS measures to detect upper motor neuron involvement. The recording of motor evoked potentials can be used to perform functional mapping of the motor cortex or in preoperative assessment of eloquent brain regions before surgical resection of brain tumors. TMS exhibits utility in assessing lumbosacral/cervical nerve root function, especially in demyelinating neuropathies, and may be of utility in localizing the site of facial nerve palsies. TMS measures also have high sensitivity in detecting subclinical corticospinal lesions in multiple sclerosis. Abnormalities in central motor conduction time or TST correlate with motor impairment and disability in MS. Cerebellar stimulation may detect lesions in the cerebellum or cerebello-dentato-thalamo-motor cortical pathways. Combining TMS with electroencephalography, provides a novel method to measure parameters altered in neurological disorders, including cortical excitability, effective connectivity, and response complexity.
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Affiliation(s)
- Steve Vucic
- Brain, Nerve Research Center, The University of Sydney, Sydney, Australia.
| | - Kai-Hsiang Stanley Chen
- Department of Neurology, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan
| | - Matthew C Kiernan
- Brain and Mind Centre, The University of Sydney; and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, Maryland, United States
| | - David H Benninger
- Department of Neurology, University Hospital of Lausanne (CHUV), Switzerland
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, Rome, Italy
| | - Paolo M Rossini
- Department of Neurosci & Neurorehab IRCCS San Raffaele-Rome, Italy
| | - Alberto Benussi
- Centre for Neurodegenerative Disorders, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Alfredo Berardelli
- IRCCS Neuromed, Pozzilli; Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Antonio Currà
- Department of Medico-Surgical Sciences and Biotechnologies, Alfredo Fiorini Hospital, Sapienza University of Rome, Terracina, LT, Italy
| | - Sandro M Krieg
- Department of Neurosurgery, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany
| | - Jean-Pascal Lefaucheur
- Univ Paris Est Creteil, EA4391, ENT, Créteil, France; Clinical Neurophysiology Unit, Henri Mondor Hospital, AP-HP, Créteil, France
| | - Yew Long Lo
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore, and Duke-NUS Medical School, Singapore
| | | | - Marcello Massimini
- Dipartimento di Scienze Biomediche e Cliniche, Università degli Studi di Milano, Milan, Italy; Istituto Di Ricovero e Cura a Carattere Scientifico, Fondazione Don Carlo Gnocchi, Milan, Italy
| | - Mario Rosanova
- Department of Biomedical and Clinical Sciences University of Milan, Milan, Italy
| | - Thomas Picht
- Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Cluster of Excellence: "Matters of Activity. Image Space Material," Humboldt University, Berlin Simulation and Training Center (BeST), Charité-Universitätsmedizin Berlin, Germany
| | - Cathy M Stinear
- Department of Medicine Waipapa Taumata Rau, University of Auckland, Auckland, Aotearoa, New Zealand
| | - Walter Paulus
- Department of Neurology, Ludwig-Maximilians-Universität München, München, Germany
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, School of Medicine, Fukushima Medical University, Japan
| | - Ulf Ziemann
- Department of Neurology and Stroke, Eberhard Karls University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany; Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Otfried-Müller-Straße 27, 72076 Tübingen, Germany
| | - Robert Chen
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital-UHN, Division of Neurology-University of Toronto, Toronto Canada
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Minic Z, O’Leary DS, Reynolds CA. Spinal Reflex Control of Arterial Blood Pressure: The Role of TRP Channels and Their Endogenous Eicosanoid Modulators. Front Physiol 2022; 13:838175. [PMID: 35283783 PMCID: PMC8904930 DOI: 10.3389/fphys.2022.838175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/26/2022] [Indexed: 01/14/2023] Open
Abstract
The spinal cord is an important integrative center for blood pressure control. Spinal sensory fibers send projections to sympathetic preganglionic neurons of the thoracic spinal cord and drive sympathetically-mediated increases in blood pressure. While these reflexes responses occur in able-bodied individuals, they are exaggerated following interruption of descending control - such as occurs following spinal cord injury. Similar reflex control of blood pressure may exist in disease states, other than spinal cord injury, where there is altered input to sympathetic preganglionic neurons. This review primarily focuses on mechanisms wherein visceral afferent information traveling via spinal nerves influences sympathetic nerve activity and blood pressure. There is an abundance of evidence for the widespread presence of this spinal reflex arch originating from virtually every visceral organ and thus having a substantial role in blood pressure control. Additionally, this review highlights specific endogenous eicosanoid species, which modulate the activity of afferent fibers involved in this reflex, through their interactions with transient receptor potential (TRP) cation channels.
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Affiliation(s)
- Zeljka Minic
- Department of Emergency Medicine Wayne State University School of Medicine, Detroit, MI, United States
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Donal S. O’Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Christian A. Reynolds
- Department of Emergency Medicine Wayne State University School of Medicine, Detroit, MI, United States
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
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Vucic S, Pavey N, Haidar M, Turner BJ, Kiernan MC. Cortical hyperexcitability: Diagnostic and pathogenic biomarker of ALS. Neurosci Lett 2021; 759:136039. [PMID: 34118310 DOI: 10.1016/j.neulet.2021.136039] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 03/04/2021] [Accepted: 06/01/2021] [Indexed: 02/06/2023]
Abstract
Cortical hyperexcitability is an early and intrinsic feature of both sporadic and familial forms of amyotrophic lateral sclerosis (ALS).. Importantly, cortical hyperexcitability appears to be associated with motor neuron degeneration, possibly via an anterograde glutamate-mediated excitotoxic process, thereby forming a pathogenic basis for ALS. The presence of cortical hyperexcitability in ALS patients may be readily determined by transcranial magnetic stimulation (TMS), a neurophysiological tool that provides a non-invasive and painless method for assessing cortical function. Utilising the threshold tracking TMS technique, cortical hyperexcitability has been established as a robust diagnostic biomarker that distinguished ALS from mimicking disorders at early stages of the disease process. The present review discusses the pathophysiological and diagnostic utility of cortical hyperexcitability in ALS.
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Affiliation(s)
- Steve Vucic
- Western Clinical School, University of Sydney, Sydney, Australia.
| | - Nathan Pavey
- Western Clinical School, University of Sydney, Sydney, Australia
| | - Mouna Haidar
- Florey Institute of Neuroscieace and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscieace and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia
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Ding Q, Lin T, Wu M, Yang W, Li W, Jing Y, Ren X, Gong Y, Xu G, Lan Y. Influence of iTBS on the Acute Neuroplastic Change After BCI Training. Front Cell Neurosci 2021; 15:653487. [PMID: 33776653 PMCID: PMC7994768 DOI: 10.3389/fncel.2021.653487] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/22/2021] [Indexed: 12/21/2022] Open
Abstract
Objective: Brain-computer interface (BCI) training is becoming increasingly popular in neurorehabilitation. However, around one third subjects have difficulties in controlling BCI devices effectively, which limits the application of BCI training. Furthermore, the effectiveness of BCI training is not satisfactory in stroke rehabilitation. Intermittent theta burst stimulation (iTBS) is a powerful neural modulatory approach with strong facilitatory effects. Here, we investigated whether iTBS would improve BCI accuracy and boost the neuroplastic changes induced by BCI training. Methods: Eight right-handed healthy subjects (four males, age: 20-24) participated in this two-session study (BCI-only session and iTBS+BCI session in random order). Neuroplastic changes were measured by functional near-infrared spectroscopy (fNIRS) and single-pulse transcranial magnetic stimulation (TMS). In BCI-only session, fNIRS was measured at baseline and immediately after BCI training. In iTBS+BCI session, BCI training was followed by iTBS delivered on the right primary motor cortex (M1). Single-pulse TMS was measured at baseline and immediately after iTBS. fNIRS was measured at baseline, immediately after iTBS, and immediately after BCI training. Paired-sample t-tests were used to compare amplitudes of motor-evoked potentials, cortical silent period duration, oxygenated hemoglobin (HbO2) concentration and functional connectivity across time points, and BCI accuracy between sessions. Results: No significant difference in BCI accuracy was detected between sessions (p > 0.05). In BCI-only session, functional connectivity matrices between motor cortex and prefrontal cortex were significantly increased after BCI training (p's < 0.05). In iTBS+BCI session, amplitudes of motor-evoked potentials were significantly increased after iTBS (p's < 0.05), but no change in HbO2 concentration or functional connectivity was observed throughout the whole session (p's > 0.05). Conclusions: To our knowledge, this is the first study that investigated how iTBS targeted on M1 influences BCI accuracy and the acute neuroplastic changes after BCI training. Our results revealed that iTBS targeted on M1 did not influence BCI accuracy or facilitate the neuroplastic changes after BCI training. Therefore, M1 might not be an effective stimulation target of iTBS for the purpose of improving BCI accuracy or facilitate its effectiveness; other brain regions (i.e., prefrontal cortex) are needed to be further investigated as potentially effective stimulation targets.
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Affiliation(s)
- Qian Ding
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Tuo Lin
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Manfeng Wu
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Wenqing Yang
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Wanqi Li
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Yinghua Jing
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Xiaoqing Ren
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
| | - Yulai Gong
- Sichuan Provincial Rehabilitation Hospital, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Guangqing Xu
- Department of Rehabilitation Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yue Lan
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
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Kleimaker M, Kleimaker A, Weissbach A, Colzato LS, Beste C, Bäumer T, Münchau A. Non-invasive Brain Stimulation for the Treatment of Gilles de la Tourette Syndrome. Front Neurol 2020; 11:592258. [PMID: 33244309 PMCID: PMC7683779 DOI: 10.3389/fneur.2020.592258] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/26/2020] [Indexed: 12/23/2022] Open
Abstract
Gilles de la Tourette Syndrome is a multifaceted neuropsychiatric disorder typically commencing in childhood and characterized by motor and phonic tics. Its pathophysiology is still incompletely understood. However, there is convincing evidence that structural and functional abnormalities in the basal ganglia, in cortico-striato-thalamo-cortical circuits, and some cortical areas including medial frontal regions and the prefrontal cortex as well as hyperactivity of the dopaminergic system are key findings. Conventional therapeutic approaches in addition to counseling comprise behavioral treatment, particularly habit reversal therapy, oral pharmacotherapy (antipsychotic medication, alpha-2-agonists) and botulinum toxin injections. In treatment-refractory Tourette syndrome, deep brain stimulation, particularly of the internal segment of the globus pallidus, is an option for a small minority of patients. Based on pathophysiological considerations, non-invasive brain stimulation might be a suitable alternative. Repetitive transcranial magnetic stimulation appears particularly attractive. It can lead to longer-lasting alterations of excitability and connectivity in cortical networks and inter-connected regions including the basal ganglia through the induction of neural plasticity. Stimulation of the primary motor and premotor cortex has so far not been shown to be clinically effective. Some studies, though, suggest that the supplementary motor area or the temporo-parietal junction might be more appropriate targets. In this manuscript, we will review the evidence for the usefulness of repetitive transcranial magnetic stimulation and transcranial electric stimulation as treatment options in Tourette syndrome. Based on pathophysiological considerations we will discuss the rational for other approaches of non-invasive brain stimulation including state informed repetitive transcranial magnetic stimulation.
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Affiliation(s)
- Maximilian Kleimaker
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany.,Department of Neurology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Alexander Kleimaker
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany.,Department of Neurology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Anne Weissbach
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Lorenza S Colzato
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Christian Beste
- Cognitive Neurophysiology, Department of Child and Adolescent Psychiatry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Tobias Bäumer
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Alexander Münchau
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
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7
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Pathophysiology of corticobasal degeneration: Insights from neurophysiological studies. J Clin Neurosci 2019; 60:17-23. [DOI: 10.1016/j.jocn.2018.10.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 10/05/2018] [Indexed: 11/20/2022]
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8
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Vucic S, van den Bos M, Menon P, Howells J, Dharmadasa T, Kiernan MC. Utility of threshold tracking transcranial magnetic stimulation in ALS. Clin Neurophysiol Pract 2018; 3:164-172. [PMID: 30560220 PMCID: PMC6275211 DOI: 10.1016/j.cnp.2018.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/17/2018] [Accepted: 10/29/2018] [Indexed: 12/21/2022] Open
Abstract
Upper motor neuron [UMN] and lower motor neuron [LMN] dysfunction, in the absence of sensory features, is a pathognomonic feature of amyotrophic lateral sclerosis [ALS]. Although the precise mechanisms have yet to be elucidated, one leading hypothesis is that UMN precede LMN dysfunction, which is induced by anterograde glutamatergic excitotoxicity. Transcranial magnetic stimulation (TMS) is a neurophysiological tool that provides a non-invasive and painless assessment of cortical function. Threshold tracking methodologies have been recently adopted for TMS, whereby changes in threshold rather than motor evoked potential (MEP) amplitude serve as outcome measures. This technique is reliable and provides a rapid assessment of cortical function in ALS. Utilisng the threshold tracking TMS technique, cortical hyperexcitability was demonstrated as an early feature in sporadic ALS preceding the onset of LMN dysfunction and possibly contributing to disease spread. Separately, cortical hyperexcitability was reported to precede the clinical onset of familial ALS. Of further relevance, the threshold tracking TMS technique was proven to reliably distinguish ALS from mimicking disorders, even in the presence of a comparable degree of LMN dysfunction, suggesting a diagnostic utility of TMS. Taken in total, threshold tracking TMS has provided support for a cortical involvement at the earliest detectable stages of ALS, underscoring the utility of the technique for probing the underlying pathophysiology. The present review will discuss the physiological processes underlying TMS parameters, while further evaluating the pathophysiological and diagnostic utility of threshold tracking TMS in ALS.
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Affiliation(s)
- Steve Vucic
- Western Clinical School, University of Sydney, Sydney, Australia
| | | | - Parvathi Menon
- Western Clinical School, University of Sydney, Sydney, Australia
| | - James Howells
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia
| | - Thanuja Dharmadasa
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia
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Kasikci T, Bek S, Koc G, Yucel M, Kutukcu Y, Odabasi Z. Transcallosal conduction in paroxysmal kinesigenic dyskinesia. Somatosens Mot Res 2018; 34:235-241. [PMID: 29334840 DOI: 10.1080/08990220.2017.1421158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Detecting whether a possible disequilibrium between the excitatory and inhibitory interhemispheric interactions in paroxysmal kinesigenic dyskinesia (PKD) exists. METHODS This study assessed measures of motor threshold, motor evoked potential latency, the cortical silent period, the ipsilateral silent period and the transcallosal conduction time (TCT) in PKD patients. Data were compared between the clinically affected hemisphere (aH) and the fellow hemisphere (fH). RESULTS The transcallosal conduction time from the aH to the fH was 11.8 ms (range = 2.3-20.7) and 13.6 ms (range = 2.8-67.7) from the fH to the aH. The difference in TCT in the affected side was significant (p = .019). CONCLUSION The findings demonstrated that, although inhibitory interneurons act normally and symmetrically between the motor cortices and transcallosal inhibition was normal and symmetrical between both sides, the onset of transcallosal inhibition was asymmetrical. The affected hemisphere's inhibition toward the unaffected hemisphere is faster compared to the inhibition provided by the fellow hemisphere. These results are consistent with an inhibitory deficit in the level of interhemispheric interactions. SIGNIFICANCE This study revealed a defect in inhibition of the motor axis could be responsible in the pathological mechanisms of kinesigenic dyskinesia.
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Affiliation(s)
| | - Semai Bek
- a Gulhane Medical Faculty , Ankara , Turkey
| | - Guray Koc
- a Gulhane Medical Faculty , Ankara , Turkey
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10
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Repetition suppression in transcranial magnetic stimulation-induced motor-evoked potentials is modulated by cortical inhibition. Neuroscience 2015; 310:504-11. [DOI: 10.1016/j.neuroscience.2015.09.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/27/2015] [Accepted: 09/21/2015] [Indexed: 01/03/2023]
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11
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Brown KE, Neva JL, Ledwell NM, Boyd LA. Use of transcranial magnetic stimulation in the treatment of selected movement disorders. Degener Neurol Neuromuscul Dis 2014; 4:133-151. [PMID: 32669907 PMCID: PMC7337234 DOI: 10.2147/dnnd.s70079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/23/2014] [Indexed: 11/23/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is a valuable technique for assessing the underlying neurophysiology associated with various neuropathologies, and is a unique tool for establishing potential neural mechanisms responsible for disease progression. Recently, repetitive TMS (rTMS) has been advanced as a potential therapeutic technique to treat selected neurologic disorders. In healthy individuals, rTMS can induce changes in cortical excitability. Therefore, targeting specific cortical areas affected by movement disorders theoretically may alter symptomology. This review discusses the evidence for the efficacy of rTMS in Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. It is hoped that gaining a more thorough understanding of the timing and parameters of rTMS in individuals with neurodegenerative disorders may advance both clinical care and research into the most effective uses of this technology.
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Affiliation(s)
| | - Jason L Neva
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | | | - Lara A Boyd
- Graduate Program in Rehabilitation Science.,Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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12
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Kallioniemi E, Säisänen L, Könönen M, Awiszus F, Julkunen P. On the estimation of silent period thresholds in transcranial magnetic stimulation. Clin Neurophysiol 2014; 125:2247-2252. [DOI: 10.1016/j.clinph.2014.03.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 03/02/2014] [Accepted: 03/10/2014] [Indexed: 11/25/2022]
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13
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Takechi U, Matsunaga K, Nakanishi R, Yamanaga H, Murayama N, Mafune K, Tsuji S. Longitudinal changes of motor cortical excitability and transcallosal inhibition after subcortical stroke. Clin Neurophysiol 2014; 125:2055-69. [PMID: 24636830 DOI: 10.1016/j.clinph.2014.01.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 12/25/2013] [Accepted: 01/02/2014] [Indexed: 11/24/2022]
Abstract
OBJECTIVE A general lack of longitudinal studies on interhemispheric interactions following stroke led us to use transcranial magnetic stimulation (TMS) to examine changes in corticospinal/intracortical excitability and transcallosal inhibition over a 1-year period following subcortical stroke. METHODS We measured TMS parameters such as motor threshold (MT), short-interval intracortical inhibition (SICI), and ipsilateral silent period (iSP) and evaluated clinical scores at three time-points (T1, T2, and T3) in 24 patients and 25 age-matched healthy subjects. RESULTS At T1, we observed reduced MTs and SICIs with prolonged iSPs in the unaffected hemisphere (UH). In contrast, increased MTs and reduced SICIs were observed in the affected hemisphere (AH). These abnormalities gradually reduced and no MEP response to TMS at T1 predicted a worse prognosis. The prolonged iSP at T1 was associated with more severe impairments, but it did not necessarily predict a worse prognosis after 1year. CONCLUSIONS UH excitability was increased at the post-acute time-period, which may have resulted in enhanced transcallosal inhibition to the AH. However, it is unclear whether there was a causal relationship between the enhanced transcallosal inhibition and the extent of clinical recovery. SIGNIFICANCE This is the first study to demonstrate changes in transcallosal inhibition over a longitudinal period following stroke.
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Affiliation(s)
- Utako Takechi
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan.
| | - Kaoru Matsunaga
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Ryoji Nakanishi
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Hiroaki Yamanaga
- Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan
| | - Nobuki Murayama
- Department of Human and Environmental Informatics, Graduate School of Science and Technology, Kumamoto University, Japan
| | - Kosuke Mafune
- Department of Mental Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan
| | - Sadatoshi Tsuji
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan
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Vucic S, Ziemann U, Eisen A, Hallett M, Kiernan MC. Transcranial magnetic stimulation and amyotrophic lateral sclerosis: pathophysiological insights. J Neurol Neurosurg Psychiatry 2013; 84:1161-70. [PMID: 23264687 PMCID: PMC3786661 DOI: 10.1136/jnnp-2012-304019] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder of the motor neurons in the motor cortex, brainstem and spinal cord. A combination of upper and lower motor neuron dysfunction comprises the clinical ALS phenotype. Although the ALS phenotype was first observed by Charcot over 100 years ago, the site of ALS onset and the pathophysiological mechanisms underlying the development of motor neuron degeneration remain to be elucidated. Transcranial magnetic stimulation (TMS) enables non-invasive assessment of the functional integrity of the motor cortex and its corticomotoneuronal projections. To date, TMS studies have established motor cortical and corticospinal dysfunction in ALS, with cortical hyperexcitability being an early feature in sporadic forms of ALS and preceding the clinical onset of familial ALS. Taken together, a central origin of ALS is supported by TMS studies, with an anterograde transsynaptic mechanism implicated in ALS pathogenesis. Of further relevance, TMS techniques reliably distinguish ALS from mimic disorders, despite a compatible peripheral disease burden, thereby suggesting a potential diagnostic utility of TMS in ALS. This review will focus on the mechanisms underlying the generation of TMS measures used in assessment of cortical excitability, the contribution of TMS in enhancing the understanding of ALS pathophysiology and the potential diagnostic utility of TMS techniques in ALS.
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Affiliation(s)
- Steve Vucic
- Sydney Medical School Westmead, University of Sydney, Sydney, New South Wales, Australia.
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15
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Vucic S, Kiernan MC. Utility of transcranial magnetic stimulation in delineating amyotrophic lateral sclerosis pathophysiology. HANDBOOK OF CLINICAL NEUROLOGY 2013; 116:561-575. [PMID: 24112924 DOI: 10.1016/b978-0-444-53497-2.00045-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder of the motor neurons in the motor cortex, brainstem, and spinal cord. The clinical phenotype of ALS is underscored by a combination of upper and lower motor neuron dysfunction. Although this phenotype was observed over 100 years ago, the site of ALS onset and the pathophysiological mechanisms underlying the development of motor neuron degeneration remain to be elucidated. Transcranial magnetic stimulation (TMS) enables noninvasive assessment of the functional integrity of the motor cortex and its corticomotoneuronal projections. To date, TMS studies have established cortical dysfunction in ALS, with cortical hyperexcitability being an early feature in sporadic forms of ALS and preceding the clinical onset of familial ALS. Taken together, a central origin of ALS is supported by TMS studies, with an anterograde dying-forward mechanism implicated in ALS pathogenesis. Of further relevance, TMS techniques reliably distinguish ALS from mimic disorders, despite a compatible peripheral disease burden, thereby suggesting a potential diagnostic utility of TMS in ALS. This chapter reviews the mechanisms underlying the generation of TMS parameters utilized in assessment of cortical excitability, the contribution of TMS in enhancing the understanding of ALS pathophysiology, and the potential diagnostic utility of TMS techniques in ALS.
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Affiliation(s)
- Steve Vucic
- Sydney Medical School Westmead, University of Sydney, Sydney, Australia; Neuroscience Research Australia, Sydney, Australia
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16
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Electromyographic bursting following the cortical silent period induced by transcranial magnetic stimulation. Brain Res 2012; 1446:40-5. [DOI: 10.1016/j.brainres.2012.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/17/2012] [Accepted: 01/18/2012] [Indexed: 11/19/2022]
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Etchell AC, Sowman PF, Johnson BW. “Shut up!” An electrophysiological study investigating the neural correlates of vocal inhibition. Neuropsychologia 2012; 50:129-38. [DOI: 10.1016/j.neuropsychologia.2011.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 11/28/2022]
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18
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Mastrolilli F, Benvenga A, Di Biase L, Giambattistelli F, Trotta L, Salomone G, Quintiliani L, Landi D, Melgari JM, Vernieri F. An unusual cause of dementia: essential diagnostic elements of corticobasal degeneration-a case report and review of the literature. Int J Alzheimers Dis 2011; 2011:536141. [PMID: 21785700 PMCID: PMC3139154 DOI: 10.4061/2011/536141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 04/21/2011] [Accepted: 05/18/2011] [Indexed: 11/20/2022] Open
Abstract
Corticobasal degeneration (CBD) is an uncommon, sporadic, neurodegenerative disorder of mid- to late-adult life. We describe a further example of the pathologic heterogeneity of this condition. A 71-year-old woman initially presented dysarthria, clumsiness, progressive asymmetric bradykinesia, and rigidity in left arm. Rigidity gradually involved ipsilateral leg; postural instability with falls, blepharospasm, and dysphagia subsequently developed. She has been previously diagnosed as unresponsive Parkinson's Disease. At our clinical examination, she presented left upper-arm-fixed-dystonia, spasticity in left lower limb and pyramidal signs (Babinski and Hoffmann). Brain MRI showed asymmetric cortical atrophy in the right frontotemporal cortex. Neuropsychological examination showed an impairment in visuospatial functioning, frontal-executive dysfunction, and hemineglect. This case demonstrates that association of asymmetrical focal cortical and subcortical features remains the clinical hallmark of this condition. There are no absolute markers for the clinical diagnosis that is complicated by the variability of presentation involving also cognitive symptoms that are reviewed in the paper. Despite the difficulty of diagnosing CBD, somatosensory evoked potentials, motor evoked potentials, long latency reflexes, and correlations between results on electroencephalography (EEG) and electromyography (EMG) provide further support for a CBD diagnosis. These techniques are also used to identify neurophysiological correlates of the neurological signs of the disease.
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Affiliation(s)
- F Mastrolilli
- Department of Neurology, "Campus Biomedico" University, Via Álvaro del Portillo, 21-00128, Rome, Italy
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Olier I, Amengual J, Vellido A. A variational Bayesian approach for the robust analysis of the cortical silent period from EMG recordings of brain stroke patients. Neurocomputing 2011. [DOI: 10.1016/j.neucom.2010.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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20
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Yazdan-Shahmorad A, Kipke DR, Lehmkuhle MJ. Polarity of cortical electrical stimulation differentially affects neuronal activity of deep and superficial layers of rat motor cortex. Brain Stimul 2010; 4:228-41. [PMID: 22032738 DOI: 10.1016/j.brs.2010.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/23/2010] [Accepted: 11/30/2010] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Cortical electrical stimulation (CES) techniques are practical tools in neurorehabilitation that are currently being used to test models of functional recovery after neurologic injury. However, the mechanisms by which CES has therapeutic effects, are not fully understood. OBJECTIVE In this study, we investigated the effects of CES on unit activity of different neuronal elements in layers of rat primary motor cortex after the offset of stimulation. We evaluated the effects of monopolar CES pulse polarity (anodic-first versus cathodic-first) using various stimulation frequencies and amplitudes on unit activity after stimulation. METHODS A penetrating single shank silicon microelectrode array enabled us to span the entirety of six layer motor cortex allowing simultaneous electrophysiologic recordings from different depths after monopolar CES. Neural spiking activity before the onset and after the offset of CES was modeled using point processes fit to capture neural spiking dynamics as a function of extrinsic stimuli based on generalized linear model methods. RESULTS We found that neurons in lower layers have a higher probability of being excited after anodic CES. Conversely, neurons located in upper cortical layers have a higher probability of being excited after cathodic stimulation. The opposing effects observed following anodic versus cathodic stimulation in upper and lower layers were frequency- and amplitude-dependent. CONCLUSIONS The data demonstrates that the poststimulus changes in neural activity after manipulation of CES parameters changes according to the location (depth) of the recorded units in rat primary motor cortex. The most effective pulse polarity for eliciting action potentials after stimulation in lower layers was not as effective in upper layers. Likewise, lower amplitudes and frequencies of CES were more effective than higher amplitudes and frequencies for eliciting action potentials. These results have important implications in the context of maximizing efficacy of CES for neurorehabilitation and neuroprosthetic applications.
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Affiliation(s)
- Azadeh Yazdan-Shahmorad
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
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21
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Carunchio I, Curcio L, Pieri M, Pica F, Caioli S, Viscomi MT, Molinari M, Canu N, Bernardi G, Zona C. Increased levels of p70S6 phosphorylation in the G93A mouse model of Amyotrophic Lateral Sclerosis and in valine-exposed cortical neurons in culture. Exp Neurol 2010; 226:218-30. [DOI: 10.1016/j.expneurol.2010.08.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 08/30/2010] [Accepted: 08/30/2010] [Indexed: 12/11/2022]
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Schütz-Bosbach S, Avenanti A, Aglioti SM, Haggard P. Don't do it! Cortical inhibition and self-attribution during action observation. J Cogn Neurosci 2009; 21:1215-27. [PMID: 18702585 DOI: 10.1162/jocn.2009.21068] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Numerous studies suggest that both self-generated and observed actions of others activate overlapping neural networks, implying a shared, agent-neutral representation of self and other. Contrary to the shared representation hypothesis, we recently showed that the human motor system is not neutral with respect to the agent of an observed action [Schütz-Bosbach, S., Mancini, B., Aglioti, S. M., & Haggard, P. Self and other in the human motor system. Current Biology, 16, 1830-1834, 2006]. Observation of actions attributed to another agent facilitated the motor system, whereas observation of identical actions linked to the self did not. Here we investigate whether the absence of motor facilitation for observing one's own actions reflects a specific process of cortical inhibition associated with self-representation. We analyzed the duration of the silent period induced by transcranial magnetic stimulation of the motor cortex in active muscles as an indicator of motor inhibition. We manipulated whether an observed action was attributed to another agent, or to the subjects themselves, using a manipulation of body ownership on the basis of the rubber hand illusion. Observation of actions linked to the self led to longer silent periods than observation of a static hand, but the opposite effect occurred when observing identical actions attributed to another agent. This finding suggests a specific inhibition of the motor system associated with self-representation. Cortical suppression for actions linked to the self might prevent inappropriate perseveration within the motor system.
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23
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Minelli A, Bortolomasi M, Scassellati C, Salvoro B, Avesani M, Manganotti P. Effects of intravenous antidepressant drugs on the excitability of human motor cortex: a study with paired magnetic stimulation on depressed patients. Brain Stimul 2009; 3:15-21. [PMID: 20633426 DOI: 10.1016/j.brs.2009.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/24/2009] [Accepted: 04/21/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The effect of various drugs was investigated by using transcranial magnetic stimulation (TMS) both in healthy subjects and patients, and the results indicated an influence of antidepressant drugs (ADs) on motor excitability. OBJECTIVE The aim of our study was to analyze the effects of two ADs, the tricyclic (TCA) clomipramine and the serotoninergic antidepressant (SSRI) citalopram on the motor cortex excitability in major depressed patients with TMS. METHODS Thirty affected subjects were placed into three groups: two received an intravenous dose of 25 mg clomipramine or 40 mg citalopram, and one received an injection of a placebo. Motor cortex excitability was studied by single and paired TMS before and after 3.5, 8, and 24 hours from administration of the drugs and placebo. Motor cortical excitability was measured using different TMS parameters: resting motor threshold (RMT), motor-evoked potential (MEP) amplitude, intracortical inhibition (ICI), and intracortical facilitation (ICF). RESULTS The results indicated a temporary but significant increase of RMT and ICI and a decrease of ICF after the administration of both drugs, with a longer inhibition for the clomipramine rather than the citalopram. MEP amplitude was not significantly affected by the antidepressant injections. CONCLUSIONS Our findings highlight that a single intravenous dose of clomipramine or citalopram exerts a significant but transitory suppression of motor cortex excitability in depressed patients. TMS represents a useful research tool in assessing the effects of motor cortical excitability of drugs used in the treatment of mental disorders.
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Affiliation(s)
- Alessandra Minelli
- Genetics Unit, IRCCS Centro S. Giovanni di Dio Fatebenefratelli, Via Piastroni 4, Brescia, Italy.
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24
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Pieri M, Carunchio I, Curcio L, Mercuri NB, Zona C. Increased persistent sodium current determines cortical hyperexcitability in a genetic model of amyotrophic lateral sclerosis. Exp Neurol 2009; 215:368-79. [DOI: 10.1016/j.expneurol.2008.11.002] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 11/06/2008] [Accepted: 11/08/2008] [Indexed: 12/11/2022]
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25
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Filipović SR, Papathanasiou I, Whurr R, Rothwell JC, Jahanshahi M. Differential effect of linguistic and non-linguistic pen-holding tasks on motor cortex excitability. Exp Brain Res 2008; 191:237-46. [PMID: 18712373 DOI: 10.1007/s00221-008-1517-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Accepted: 07/21/2008] [Indexed: 10/21/2022]
Abstract
Writing and drawing are unique human activities. They are complex high-precision actions, which involve not only the motor system but also various cognitive systems, such as attention, short-term memory, action control, and language. In relation to motor control, the study of writing and drawing is of great interest as they provide insight in the interaction between motor control processes and the concurrent non-motor processes. Although sharing similar motor and mechanical demands, writing and drawing involve different levels of linguistic/semantic load and thus may be associated with different modulation of motor cortical excitability. Here, we have used transcranial magnetic stimulation to study separately activation of excitatory and inhibitory mechanisms of the motor cortex during performance of writing and drawing acts as well as during simple pen-squeezing task. While cortical excitatory mechanisms appeared to be saturated by the pure motor demands of the tasks, and thus not amenable to modulation by the tasks' linguistic load, variation in cortical inhibitory activity was the main vehicle for differential modulation of motor cortical excitability by linguistic demands of the tasks. The results of this study highlight the importance of cortical inhibitory mechanisms in the physiology of higher cognitive activities. They also provide further evidence that the task specific modulation of the excitability of the motor cortex goes beyond motor complexity of the task and is also dependant on associated cognitive components.
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Affiliation(s)
- Sasa R Filipović
- Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
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Chen R, Cros D, Curra A, Di Lazzaro V, Lefaucheur JP, Magistris MR, Mills K, Rösler KM, Triggs WJ, Ugawa Y, Ziemann U. The clinical diagnostic utility of transcranial magnetic stimulation: Report of an IFCN committee. Clin Neurophysiol 2008; 119:504-532. [DOI: 10.1016/j.clinph.2007.10.014] [Citation(s) in RCA: 348] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 10/12/2007] [Accepted: 10/18/2007] [Indexed: 12/11/2022]
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Attarian S, Verschueren A, Pouget J. Magnetic stimulation including the triple-stimulation technique in amyotrophic lateral sclerosis. Muscle Nerve 2007; 36:55-61. [PMID: 17443663 DOI: 10.1002/mus.20789] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To study the relative importance of upper motor neuron (UMN) dysfunction in the weakness of amyotrophic lateral sclerosis (ALS) and to compare the sensitivity of several transcranial magnetic stimulation (TMS) parameters as means of assessing UMN impairment in ALS, we used TMS to evaluate one upper limb of 63 patients. The triple-stimulation technique (TST) and silent period (SP) were found to be the most frequently abnormal parameters (55.6% and 47.6%, respectively), without significant difference in their diagnostic sensitivity. The SP was found to be a useful parameter in patients with suspected or possible ALS. A positive correlation was found between weakness and the TST amplitude ratio, indicating that weakness may partly be caused by UMN dysfunction. Thus, the TST provides a quantitative tool for assessing UMN conduction failure. When used in association with the SP, the TST provides a sensitive diagnostic tool for use on ALS patients.
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Affiliation(s)
- Shahram Attarian
- Department of Neurology and Neuromuscular Diseases, CHU La Timone, 264 rue Saint-Pierre, 13385 Marseille, France.
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28
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Sartucci F, Tovani S, Murri L, Sagliocco L. Motor and somatosensory evoked potentials in Autosomal Dominant Hereditary Spastic Paraparesis (ADHSP) linked to chromosome 2p, SPG4. Brain Res Bull 2007; 74:243-9. [PMID: 17720546 DOI: 10.1016/j.brainresbull.2007.06.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 06/05/2007] [Accepted: 06/21/2007] [Indexed: 12/11/2022]
Abstract
The aim of our study was to evaluate Motor Evoked Potentials (MEPs) and cortical excitability, using Transcranial Magnetic Stimulation (TMS) as well as short latency Somatosensory Evoked Potentials (SEPs) in Autosomal Dominant Hereditary Spastic Paraparesis (ADHSP) patients. MEPs were recorded from upper and lower limb muscles in 12 patients (7 m and 5f) affected by ADHSP with spastin mutation (SPG4). We measured: (i) motor threshold (MTh); (ii) total motor conduction time (TMCT); (iii) direct and indirect central motor conduction time (d-CMCT and i-CMCT) calculated by subtracting from the cortical latency those obtained on magnetic spinal stimulation (d-PMCT) and via the F-wave method (i-PMCT); (iv) MEP amplitude (MEP/Mmax ratio%) and (v) duration of the cortical silent period (CSP). Latency, amplitude and persistence of the F-wave obtained with electrical nerve stimulation were also considered; H reflex was also tested from lower extremities. SEPs were recorded from spine and scalp sites following median and posterior tibial nerve stimulation; conventional latency and amplitude measurements were performed. In a comparison with the control group, the MTh recording from lower limbs was significantly higher (67.5 +/- 7.7% versus 52.5 +/- 6.9%), MEPs were absent in one case and showed reduced amplitude in the remainders (22.9 +/- 12.6% versus 66.3 +/- 25.9% of M wave); TMCT resulted to be abnormal (36.5 +/- 3.9 ms versus 27.1 +/- 1.4 ms) and d-CMCT as well as i-CMCT were significantly prolonged (23.1 +/- 3.5 ms versus 13.8 +/- 1.3 ms; and 20.1 +/- 3.4 ms versus 10.6 +/- 1.3 ms, respectively). The CSP, which was normal from the hands, was significantly shortened from the legs and correlated with spasticity scoring (Ashworth scale). Cortical SEPs from lower limbs were abnormal in all cases, whereas SEPs by stimulation of median nerves were normal; F-wave parameters from upper limbs showed no abnormalities, whereas an increased persistence was detected from lower limbs; H reflex amplitudes resulted larger compared with controls. Moreover, shortening of the CSP, being correlated with the Ashworth scale, can be considered an electrophysiological marker of spasticity that seems to arise from impairment of the supraspinal or intracortical inhibitory pathways with an additional contribution of increased segmental motor neuron excitability. These data prove the existence of comparable neurophysiological abnormalities in ADHSP with spastin mutation (SPG4) when long ascending and descending pathways are involved.
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Affiliation(s)
- F Sartucci
- Department of Neurosciences, Clinical Neurology, Pisa University Medical School, Pisa, Italy.
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29
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O'Neill GN, Gonzalez RG, Cros DP, Ackerman RH, Brown RH, Stemmer-Rachamimov A. Case records of the Massachusetts General Hospital. Case 22-2006--a 77-year-old man with a rapidly progressive gait disorder. N Engl J Med 2006; 355:296-304. [PMID: 16855271 DOI: 10.1056/nejmcpc069013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Khedr EM, Ahmed MA, Mohamed KA. Motor and visual cortical excitability in migraineurs patients with or without aura: transcranial magnetic stimulation. Neurophysiol Clin 2006; 36:13-8. [PMID: 16530139 DOI: 10.1016/j.neucli.2006.01.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND AND PURPOSE OF STUDY Controversy surrounds measures of visual and motor cortical excitability in migraineurs: some authors report that interictal excitability is increased, others decreased. The aim of this work was to provide further evidence about motor and visual cortical excitability in migraineurs between attacks. PATIENTS AND METHODS Twenty-eight migraineurs patients, 18 with aura and 10 patients without aura and 20 healthy right-handed, age and sex matched volunteers were included in the study. Each subject underwent transcranial magnetic stimulation and was submitted to the following: determination of resting motor threshold (rMT), silent period (SP), MEP input-output curves, phosphene threshold (PT). RESULTS Patients had lower rMT, shorter SP, and increased MEP recruitment compared with control group. There was an increased prevalence of phosphene (85%) as well as lower PT (63% of the stimulator output) in migraineurs compared with control group (75%, and 72%, respectively). There was a significant negative correlation between duration of attacks and PT (P = 0.02). No significant differences between patients with aura and without aura in different parameters of cortical excitability. CONCLUSION Our findings confirm that the motor and visual cortexes are hyperexcitable and this appears partly to be consequent upon a failure of inhibitory circuits.
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Affiliation(s)
- Eman M Khedr
- Neuropsychiatry Department, Assiut University Hospital, Assiut, Egypt.
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Attarian S, Pouget J, Schmied A. Covariation of corticospinal efficiency and silent period in motoneuron diseases. Muscle Nerve 2006; 34:178-88. [PMID: 16691593 DOI: 10.1002/mus.20570] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
For a better understanding of the changes affecting the cortically induced silent period (SP) in motoneuron disease, the excitatory and inhibitory effects of transcranial magnetic stimulation were explored repeatedly in 8 patients with amyotrophic lateral sclerosis (ALS), 3 patients with Kennedy's disease (KD), and 10 healthy subjects. In KD, the background electromyogram (EMG) and the motor evoked potential (MEP) area were both enhanced. However, neither the corticospinal efficiency (MEP gain, the ratio between MEP and background EMG) nor the duration of the SP differed from healthy subjects. In ALS patients, the MEP gain and the SP duration decreased conspicuously with time. We conclude that use of the MEP gain improves detection of corticospinal dysfunction in ALS patients. Part of the SP shortening in ALS seems to reflect the reduced activation of cortical or spinal inhibitory networks by the abnormal corticospinal pathway.
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Affiliation(s)
- S Attarian
- Department of Neurology and Neuromuscular Diseases, CHU La Timone, 264 rue Saint-Pierre, 13385 Marseille, France.
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van Kuijk AA, Pasman JW, Geurts ACH, Hendricks HT. How salient is the silent period? The role of the silent period in the prognosis of upper extremity motor recovery after severe stroke. J Clin Neurophysiol 2005; 22:10-24. [PMID: 15689709 DOI: 10.1097/01.wnp.0000150975.83249.71] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) has been successful in the prediction of motor recovery in acute stroke patients with initially severe paresis or paralysis of the upper extremity. Motor evoked potentials (MEP) appear to have a high specificity but a rather low sensitivity with regard to motor recovery. The silent period (SP) has been proposed as an additional factor to the MEP for predicting motor recovery that might optimize the sensitivity of TMS. The authors reviewed the literature and case series focusing on the additional value of the SP to the MEP for predicting poststroke hand motor recovery. Studies that have analyzed the SP for predicting poststroke motor recovery have rather inconsistent results and suffer from heterogeneity in technical methods, methodology, and patient characteristics. In most studies, prolonged SPs have been found immediately after stroke, whereas in the (sub)acute phase thereafter, different patterns of SP duration have been found. These differences are thought to be related to stroke localization, though contraction-induced reduction phenomena and recovery-related intracortical phenomena may also be responsible. Although the SP might be used to identify clinically silent or minor strokes, in acute stroke patients with initial severe paresis or paralysis, the SP seems to have no additional value to MEP for predicting poststroke motor recovery. Nevertheless, the SP (poststroke-reduced SPs and contraction-induced inhibitory phenomena) has been proposed as a prognostic factor for poststroke spasticity. This review emphasizes the significance of the SP in predicting poststroke motor recovery and spasticity. Although the relation among the SP, recovery-related intracortical phenomena, and spasticity remains unclear, a neurophysiologic model underlying the SP is discussed. However, more research is needed on the value of the SP for predicting poststroke spasticity.
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Affiliation(s)
- Annette A van Kuijk
- Department of Rehabilitation Medicine, University Medical Centre Sint Radboud, Nijmegen, The Netherlands
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Attarian S, Azulay JP, Lardillier D, Verschueren A, Pouget J. Transcranial magnetic stimulation in lower motor neuron diseases. Clin Neurophysiol 2005; 116:35-42. [PMID: 15589181 DOI: 10.1016/j.clinph.2004.07.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2004] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To study the diagnostic value of transcranial magnetic stimulation (TMS) in a group of patients with lower motor neuron disease (LMND). Among LMND, several chronic immune mediate motor neuropathies may simulate amyotrophic lateral sclerosis (ALS). METHODS Forty patients with LMND were included TMS was performed at the first visit. The patients were seen prospectively every 3 months for a period of 1-4 years. RESULTS Three different groups were distinguished at the end of follow-up: (1) ALS group with 7 patients, (2) Pure motor neuropathy with 14 patients and (3) Other LMND including 12 patients with hereditary spinal amyotrophy, 3 patients with Kennedy's disease and 4 patients with post-poliomyelitis. On the basis of the results of TMS variables, 6 out of 7 ALS patients had abnormality of silent period (SP) associated or not with abnormality of excitatory threshold or amplitude ratio. Patients with pure motor neuropathy had normal SP and amplitude ratio. Four out of 14 patients had increased central motor conduction time (CMCT), one had increased CMCT and excitatory threshold, and one patient had a slightly increased excitatory threshold. Considering the abnormality of TMS variables in the groups, SP, excitatory threshold, and amplitude ratio were chosen in a post-hoc attempt to select variables yielding high sensitivity and specificity. The overall sensitivity of TMS for diagnosis of ALS among LMND was 85.7%, its specificity was 93.9%. When only the abnormality of SP was taken into account, the sensitivity was unchanged. But the specificity was improved to 100%. CONCLUSIONS TMS helped to distinguish suspected ALS from pure motor neuropathy.
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Affiliation(s)
- S Attarian
- Department of Neurology and Neuromuscular Diseases, CHU La Timone, 264 rue Saint-Pierre, 13385 Marseilles, France.
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Kimiskidis VK, Papagiannopoulos S, Sotirakoglou K, Kazis DA, Kazis A, Mills KR. Silent period to transcranial magnetic stimulation: construction and properties of stimulus-response curves in healthy volunteers. Exp Brain Res 2005; 163:21-31. [PMID: 15690156 DOI: 10.1007/s00221-004-2134-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 10/07/2004] [Indexed: 11/28/2022]
Abstract
Silent period (SP) is widely used in transcranial magnetic stimulation studies. Methodologically, SP is usually elicited at stimulus intensities corresponding to a certain percentage of corticomotor threshold. Because this approach might lead to factitious SP changes, the present study was designed to develop, in a stepwise manner, a method for investigating SP independently of corticomotor threshold. First, stimulus-response (S-R) curves of SP against stimulus intensity (SI) were constructed and quantitatively described in healthy volunteers. Second, various methodological issues such as the optimum model for describing the relationship between SP duration and SI and the importance of the type of stimulating coil were addressed. Finally, the proposed method and a commonly used method (eliciting SPs at 130% MT SI) were directly compared for a group of epileptic patients for whom administration of oxcarbazepine resulted in significant corticomotor threshold elevation. Twenty-one subjects (eleven females, median age, 38 years) were studied. SPs were obtained with a figure-of-eight coil using a standardized procedure (recording, FDI). Pilot experiments indicated that at least four trials were required, at each intensity level, to estimate the mean SP duration within 10% of the true mean. Therefore, SPs were determined from the average of four trials with 5% increments from 5 to 100% maximum SI. In a second set of experiments, SPs were obtained for fifteen subjects using a circular coil. In a third set of experiments, eight epileptic patients were studied before and after administration of oxcarbazepine (mean dose 1553 mg, range 900-1800 mg). The S-R curves were fitted to a Boltzman function and to first-order to fourth-order polynomial and sigmoid functions. The Boltzman function described the data accurately (R2=0.947-0.990). In addition, direct comparison of the six models with an F-test proved the superiority of the first. The best-fit parameters of the reference curve, i.e. the maximum and minimum values, the slope, and V50 (the SI at which SP duration is halfway between Min and Max) were 230.8+/-3.31 ms (x+/-SEM), -11.51+/-3.31 ms, 11.56+/-0.65%, and 49.82+/-0.65%, respectively. When the curves obtained with the circular coil were compared with those obtained with the figure-of-eight coil, there were differences between V50 (51.69+/-0.72 vs 47.95+/-0.82, P<0.001) and SP threshold (31.15 vs 24.77, P<0.01) whereas the other best-fit values did not differ significantly. Oxcarbazepine increased corticomotor threshold from 45.3+/-5.8% at baseline to 59.4+/-10.4% (P<0.001). According to the commonly used method, the drug significantly prolonged SP (from 117.6+/-42.4 ms to 143.5+/-46.5 ms, P<0.001) and, consequently, enhanced brain inhibition. In contrast, study of the SP curves led to the conclusion that oxcarbazepine does not affect the Max value and slope but significantly increases V50 and SP threshold (from 54.5+/-4.9% to 59.9+/-7.2% and from 29.1+/-6.4% to 34.6+/-6.8%, respectively, P<0.01). These findings imply that oxcarbazepine does not enhance brain inhibitory mechanisms. Thus, in situations characterized by significant changes in corticomotor threshold the proposed method provides results clearly different from a commonly used approach. It is concluded that S-R curves obtained with a figure-of-eight coil in 5% increments and fitted to a Boltzman function provide an accurate, comprehensive, and clinically applicable method for exploring SP.
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Affiliation(s)
- V K Kimiskidis
- Department of Neurology III, G. Papanikolaou Hospital, Aristotle University of Thessaloniki, 57010 Thessaloniki, Greece.
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Stefan K, Wycislo M, Classen J. Modulation of Associative Human Motor Cortical Plasticity by Attention. J Neurophysiol 2004; 92:66-72. [PMID: 14724259 DOI: 10.1152/jn.00383.2003] [Citation(s) in RCA: 358] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of attention in generating motor memories remains controversial principally because it is difficult to separate the effects of attention from changes in kinematics of motor performance. We attempted to disentangle attention from performance effects by varying attention while plasticity was induced in human primary motor cortex by external stimulation in the absence of voluntary movement. A paired associative stimulation (PAS) protocol was employed consisting of repetitive application of single afferent electric stimuli, delivered to the right median nerve, paired with single-pulse transcranial magnetic stimulation (TMS) over the optimal site for activation of the right abductor pollicis brevis muscle (APB) to generate near-synchronous events in the left primary motor cortex. In experiment 1, the spatial location of attention was varied. PAS failed to induce plasticity when the subject's attention was directed to their left hand, away from the right target hand the cortical representation of which was being stimulated by PAS. In experiment 2, the grade of attention to the target hand was manipulated. PAS-induced plasticity was maximal when the subject viewed their target hand, and its magnitude was slightly reduced when the subject could only feel their hand. Conversely, plasticity was completely blocked when the subject's attention was diverted from the target hand by a competing cognitive task. A similar modulation by attention was observed for PAS-induced changes in the duration of the silent period evoked by TMS in voluntarily contracted muscle. Associative plasticity in the human motor cortex depends decisively on attention.
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Affiliation(s)
- Katja Stefan
- Human Cortical Physiology and Motor Control Laboratory, Department of Neurology, University of Würzburg, Germany
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Robol E, Fiaschi A, Manganotti P. Effects of citalopram on the excitability of the human motor cortex: a paired magnetic stimulation study. J Neurol Sci 2004; 221:41-6. [PMID: 15178212 DOI: 10.1016/j.jns.2004.03.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Revised: 02/18/2004] [Accepted: 03/08/2004] [Indexed: 11/29/2022]
Abstract
Several recent reports suggest the possibility of monitoring pharmacological effects on brain excitability through transcranial magnetic stimulation (TMS). Different drugs have been studied using paired magnetic stimulation in normal subjects and patients. In particular, it has been suggested that antidepressant drugs may have an appreciable effect on motor excitability. The aim of the present study was to investigate motor area excitability in normal subjects after oral administration of a single dose of citalopram, a selective serotonin reuptake inhibitor (SSRI) antidepressant. Motor cortex excitability was studied by single and paired transcranial magnetic stimulation before and 2.5 and 36 (t1/2=36 h) h after oral administration of 30 mg of citalopram. Cortical excitability was measured using different transcranial magnetic stimulation parameters: motor threshold (MT), motor-evoked potential (MEP) amplitude and latency, motor recruitment, duration of cortical silent period (CSP), intracortical inhibition and intracortical facilitation. Spinal excitability and peripheral nerve conduction were measured by F response and M wave. Temporary but significant increases in motor threshold, motor-evoked potentials, silent period and intracortical inhibition were observed 2.5 h after drug administration, without any significant changes in motor-evoked potential amplitude and latency and spinal excitability parameters. Our findings suggest that a single oral dose of citalopram can induce significant but transitory suppression of motor cortex excitability in normal subjects.
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Affiliation(s)
- Elisa Robol
- Dipartimento di Scienze Neurologiche e della Visione, Sezione Neurologia Riabilitativa, Policlinico Giambattista Rossi, Università di Verona, Via delle Menegone, 10-Verona 37134, Italy.
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Rushworth MFS, Johansen-Berg H, Göbel SM, Devlin JT. The left parietal and premotor cortices: motor attention and selection. Neuroimage 2004; 20 Suppl 1:S89-100. [PMID: 14597301 DOI: 10.1016/j.neuroimage.2003.09.011] [Citation(s) in RCA: 369] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is well established that the premotor cortex has a central role in the selection of movements. The role of parts of the parietal cortex in movement control has proved more difficult to describe but appears to be related to the preparation and the redirection of movements and movement intentions. We have referred to some of these processes as motor attention. It has been known since the time of William James that covert motor attention can be directed to an upcoming movement just as visuospatial attention can be directed to a location in space. While some parietal regions, particularly in the right hemisphere, are concerned with covert orienting and the redirecting of covert orienting it may be useful to consider other parietal regions, in the anterior inferior parietal lobule and in the posterior superior parietal lobule, particularly in the left hemisphere, as contributing to motor attention. Such parts of the parietal lobe are activated in neuroimaging experiments when subjects covertly prepare movements or switch intended movements. Lesions or transcranial magnetic stimulation (TMS) affect the redirecting of motor attention. The difficulties apraxic patients experience when sequencing movements may partly be due to an inability to redirect motor attention from one movement to another. The role of the premotor cortex in selecting movements is also lateralized to the left hemisphere. Damage to left hemisphere movement selection mechanisms may also contribute to apraxia. If, however, it remains intact after a stroke then the premotor cortex may contribute to the recovery of arm movements. A group of patients with unilateral left hemisphere lesions and impaired movements in the contralateral right hand was studied. Functional magnetic resonance imaging showed that in some cases the premotor cortex in the intact hemisphere was more active when the stroke-affected hand was used. TMS in the same area in the same patients had the most disruptive effect on movements. In summary, patterns of motor impairment and recovery seen after strokes can partly be explained with reference to the roles of the parietal and premotor cortices in motor attention and selection.
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Affiliation(s)
- M F S Rushworth
- Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD, UK.
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Cortical threshold and excitability measurements. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1567-4231(04)04017-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Cincotta M, Borgheresi A, Gambetti C, Balestrieri F, Rossi L, Zaccara G, Ulivelli M, Rossi S, Civardi C, Cantello R. Suprathreshold 0.3 Hz repetitive TMS prolongs the cortical silent period: potential implications for therapeutic trials in epilepsy. Clin Neurophysiol 2003; 114:1827-33. [PMID: 14499744 DOI: 10.1016/s1388-2457(03)00181-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To investigate the after-effects of 0.3 Hz repetitive transcranial magnetic stimulation (rTMS) on excitatory and inhibitory mechanisms at the primary motor cortex level, as tested by single-pulse TMS variables. METHODS In 9 healthy subjects, we studied a wide set of neurophysiological and behavioral variables from the first dorsal interosseous before (Baseline), immediately after (Post 1), and 90 min after (Post 2) the end of a 30 min long train of 0.3 Hz rTMS delivered at an intensity of 115% resting motor threshold (RMT). Variables under investigation were: maximal M wave, F wave, and peripheral silent period after ulnar nerve stimulation; RMT, amplitude and stimulus-response curve of the motor evoked potential (MEP), and cortical silent period (CSP) following TMS; finger-tapping speed. RESULTS The CSP was consistently lengthened at both Post 1 and Post 2 compared with Baseline. The other variables did not change significantly. CONCLUSIONS These findings suggest that suprathreshold 0.3 Hz rTMS produces a relatively long-lasting enhancement of the inhibitory mechanisms responsible for the CSP. These effects differ from those, previously reported, of 0.9-1 Hz rTMS, which reduces the excitability of the circuits underlying the MEP and does not affect the CSP. This provides rationale for sham-controlled trials aiming to assess the therapeutic potential of 0.3 Hz rTMS in epilepsy.
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Affiliation(s)
- M Cincotta
- Unita' Operativa di Neurologia, Azienda Sanitaria di Firenze, Ospedale S. Maria Nuova, Piazza S. Maria Nuova, 1 50122, Florence, Italy.
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Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive and painless method of stimulating the cerebral cortex that allows the study of cortical excitability and inhibition. This article describes the technique, the parameters most commonly studied, the clinical applications of TMS, and potential research applications.
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Affiliation(s)
- Valerie Reid
- Department of Neurology, Beaumont Hospital, Dublin 9, Ireland.
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Tataroglu C, Genc A, Idiman E, Cakmur R, Idiman F. Cortical silent period and motor evoked potentials in patients with multiple sclerosis. Clin Neurol Neurosurg 2003; 105:105-10. [PMID: 12691802 DOI: 10.1016/s0303-8467(02)00127-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In order to determine the importance of central motor conduction time (CMCT) and silent period (SP) in patients with multiple sclerosis (MS), we enrolled this clinical and electrophysiological study. Additionally, we planned to compare the correlation between electrophysiological findings and clinical status. We examined 58 patients with definite MS and 31 controls. Patients were classified as relapsing-remitting (N: 37), secondary progressive (N: 21) groups. Eleven out of 58 patients with MS had no neurological findings (subclinical patients). We evaluated CMCT and the duration of SP. Prolonged CMCT latency was shown in 75.2% of patients. We observed SP abnormalities in 69% of patients. In subclinical patients, SP abnormalities (six of 11) were observed more common than CMCT (two of 11). The duration of SP was extremely prolonged in MS patients with cerebellar dysfunction. When the both electrophysiological parameters are taken into account, the abnormality ratio was determined as 89.7%. Our results indicate that CMCT and SP analysis are complementary tests in evaluating motor pathways of patients with MS. We observed a relationship between cerebellar dysfunction and SP prolongation. It is suggested that, SP can be applied in patients with pure cerebellar dysfunction and it can be a valuable test in subclinical cases with MS.
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Affiliation(s)
- Cengiz Tataroglu
- Department of Neurology, Faculty of Medicine, Mersin University, Mersin 33079, Turkey.
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Abstract
Transcranial magnetic stimulation (TMS) is a non-invasive tool for the electrical stimulation of neural tissue, including cerebral cortex, spinal roots, and cranial and peripheral nerves. TMS can be applied as single pulses of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Single stimuli can depolarise neurons and evoke measurable effects. Trains of stimuli (repetitive TMS) can modify excitability of the cerebral cortex at the stimulated site and also at remote areas along functional anatomical connections. TMS might provide novel insights into the pathophysiology of the neural circuitry underlying neurological and psychiatric disorders, be developed into clinically useful diagnostic and prognostic tests, and have therapeutic uses in various diseases. This potential is supported by the available studies, but more work is needed to establish the role of TMS in clinical neurology.
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Affiliation(s)
- Masahito Kobayashi
- Laboratory for Magnetic Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Abbruzzese G, Trompetto C. Clinical and research methods for evaluating cortical excitability. J Clin Neurophysiol 2002; 19:307-21. [PMID: 12436087 DOI: 10.1097/00004691-200208000-00005] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The evaluation of motor cortical output after transcranial magnetic stimulation (TMS) is a means of investigating how the motor cortex reacts to external stimuli (i.e., a method to assess the excitability of the motor cortex). The recording of the descending volleys at the surface of the spinal cord provides a direct measure of the motor cortical output. However, this approach is highly invasive and can be used only during particular conditions. On the other hand, electromyographic recordings of the motor phenomena induced by TMS provide a completely painless, noninvasive, indirect measure of the cortical output, with these phenomena obviously reflecting the excitability of the spinal motoneurons as well as that of the muscle itself. The authors review how the electromyographic activity induced by TMS can provide valuable information about motor cortical excitability for use in clinical practice and research.
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Affiliation(s)
- Giovanni Abbruzzese
- Laboratory of Clinical Neurophysiology, Department of Neurological Sciences & Vision, University of Genoa, Italy.
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Fitzgerald PB, Brown TL, Daskalakis ZJ. The application of transcranial magnetic stimulation in psychiatry and neurosciences research. Acta Psychiatr Scand 2002; 105:324-40. [PMID: 11942939 DOI: 10.1034/j.1600-0447.2002.1r179.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Over recent years transcranial magnetic stimulation (TMS) has become widely applied in the study of neuropsychiatric disorders. The aim of this article is to review the application of TMS as an investigative tool and as a potential therapeutic modality in psychiatric disorders. METHOD A comprehensive literature review. RESULTS When applied as an investigative tool, TMS provides innovative ways to directly study the excitability of the cortex, cortical regional connectivity, the plasticity of brain responses and cognitive functioning in illness and disease states. A number of studies suggest the potential of treatment with TMS in disease states, especially in patients with depression, although difficulties exist with the interpretation of the published literature. CONCLUSION TMS has a considerable role in neuropsychiatric research. It appears to have considerable potential as a therapeutic tool in depression, and perhaps a role in several other disorders, although widespread application requires larger trials and establishment of sustained response.
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Affiliation(s)
- P B Fitzgerald
- Dandenong Psychiatry Research Centre, Department of Psychological Medicine, Monash University, PO Box 956, Dandenong, Victoria 3175, Australia.
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Perretti A, Pellecchia MT, Lanzillo B, Campanella G, Santoro L. Excitatory and inhibitory mechanisms in Wilson's disease: investigation with magnetic motor cortex stimulation. J Neurol Sci 2001; 192:35-40. [PMID: 11701150 DOI: 10.1016/s0022-510x(01)00594-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have evaluated cortical excitability in nine patients affected by Wilson's disease (WD) using transcranial magnetic (TMS) and electric (TES) cortical stimulation and central silent period (CSP) data. A clinical score was derived from the sum of scores assigned to extrapyramidal, pyramidal and cerebellar signs. All patients underwent TMS. Motor evoked potentials (MEPs) from abductor pollicis brevis (APB) and tibialis anterior (TA) muscles were recorded. MEP threshold and amplitude, central motor conduction time (CMCT), CSP threshold, CSP and peripheral silent period (PSP) duration were measured. Three patients also underwent transcranial bifocal electric cortical stimulation (TES) and MEPs were recorded from the APB muscle, and CMCT, MEP threshold and amplitude were measured. TMS MEPs were absent from relaxed muscles in six patients and from contracted muscles in three. CMCT was prolonged in six patients. APB CMCT correlated with clinical score. In three patients in whom TMS revealed abnormal or no MEP, TES MEPs were of normal threshold and amplitude. The CSP threshold was increased in seven patients, and CSP was absent in one. These results suggest an intracortical presynaptic motor dysfunction in WD.
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Affiliation(s)
- A Perretti
- Department of Neurological Sciences, University of Naples Federico II, Via Sergio Pansini 5, 80131 Naples, Italy.
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Manganotti P, Bortolomasi M, Zanette G, Pawelzik T, Giacopuzzi M, Fiaschi A. Intravenous clomipramine decreases excitability of human motor cortex. A study with paired magnetic stimulation. J Neurol Sci 2001; 184:27-32. [PMID: 11231029 DOI: 10.1016/s0022-510x(00)00495-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Several recent reports suggest the possibility of monitoring pharmacological effects on brain excitability through transcranial magnetic stimulation (TMS). In these studies, paired magnetic stimulation has been used in normal subjects and on patients who were taking different antiepileptic drugs. The aim of our study was to investigate motor area excitability on depressed patients after intravenous administration of a single dose of clomipramine, a tricyclic antidepressant. Motor cortex excitability was studied by single and paired transcranial magnetic stimulation (TMS) before and after 4, 8 and 24 h from intravenous administration of 25 mg of clomipramine. Cortical excitability was measured using different TMS parameters: motor threshold (MT), motor evoked potential (MEP) amplitude, duration of cortical silent period (CSP), intracortical inhibition (ICI) and intracortical facilitation (ICF). Spinal excitability and peripheral nerve conduction was measured by F response and M wave. A temporary but significant increase of motor threshold and intracortical inhibition and a decrease of intracortical facilitation were observed 4 h following drug administration. MEP amplitude, cortical silent period, F response and M wave were not significantly affected by drug injection. Our findings suggest that a single intravenous dose of clomipramine can exert a significant but transitory suppression of motor cortex excitability in depressed patients. TMS represents a useful research tool in assessing the effects of motor cortical excitability of neuropsychiatric drugs used in psychiatric disease.
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Affiliation(s)
- P Manganotti
- Sezione di Neurologia Riabilitativa, Sezione di Neurologia, Policlinico GB Rossi, Universita' di Verona, Verona, Italy.
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Sanger TD, Garg RR, Chen R. Interactions between two different inhibitory systems in the human motor cortex. J Physiol 2001; 530:307-17. [PMID: 11208978 PMCID: PMC2278414 DOI: 10.1111/j.1469-7793.2001.0307l.x] [Citation(s) in RCA: 383] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Intracortical inhibition in the human motor cortex has been previously demonstrated using paired-pulse transcranial magnetic stimulation (TMS) protocols at short intervals (1-6 ms; short interval intracortical inhibition, SICI) with a subthreshold conditioning pulse preceding a suprathreshold test pulse, and at long intervals (50-200 ms; long interval intracortical inhibition, LICI) with suprathreshold conditioning and test pulses. We investigated whether different circuits mediate these inhibitory phenomena and how they interact. In nine healthy volunteers, we applied TMS to the motor cortex and recorded motor evoked potentials from the first dorsal interosseous muscle. With increasing test pulse strength, LICI decreases but SICI tends to increase. There was no correlation between the degree of SICI and LICI. We tested the interactions between SICI and LICI. SICI was reduced or eliminated in the presence of LICI. Loss of SICI was seen even with a conditioning stimulus too weak to induce significant LICI. Our findings demonstrate that different cell populations mediate SICI and LICI. The results are consistent with the hypothesis that LICI inhibits SICI through presynaptic GABAB receptors. Testing of SICI in the presence of LICI may be a non-invasive way of evaluating inhibitory interactions in the human motor cortex.
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Affiliation(s)
- T D Sanger
- Division of Neurology, Toronto Western Hospital and Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
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Stefan K, Kunesch E, Benecke R, Classen J. Effects of riluzole on cortical excitability in patients with amyotrophic lateral sclerosis. Ann Neurol 2001. [DOI: 10.1002/ana.107] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Manganotti P, Bongiovanni LG, Zanette G, Fiaschi A. Early and late intracortical inhibition in juvenile myoclonic epilepsy. Epilepsia 2000; 41:1129-38. [PMID: 10999552 DOI: 10.1111/j.1528-1157.2000.tb00318.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE We investigated 15 patients with juvenile myoclonic epilepsy (JME) by subjecting them to single and paired transcranial magnetic stimulation to test the hypothesis that motor cortical inhibition may be abnormal in this form of benign epilepsy. METHODS Different conditioning paradigms of paired transcranial magnetic stimulation were used with interstimulus intervals (ISIs) of varying lengths (1 to 400 milliseconds) to investigate changes in balance between excitatory and inhibitory intracortical circuits. RESULTS Motor evoked potential (MEP) inhibition at ISIs of 1 to 4 milliseconds was significantly lower in JME patients than in age-matched healthy controls (p < 0.001), whereas no significant differences in MEP inhibition were noted at long ISIs (100 to 150 milliseconds). This pattern was observed in both hemispheres in seven of seven patients studied bilaterally and was present in both treated and untreated patients. There were no group differences between JME patients and controls in intracortical facilitation, motor threshold, MEP amplitude, and cortical silent period. CONCLUSIONS We documented a different pattern of MEP inhibition in JME patients, suggesting impaired functioning of inhibitory interneuronal circuits, which may account for the hyperexcitability of the motor system in this form of epilepsy.
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Affiliation(s)
- P Manganotti
- Dipartimento di Scienze Neurologiche e della Visione, University of Verona, Italy
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Shimizu T, Hino T, Komori T, Hirai S. Loss of the muscle silent period evoked by transcranial magnetic stimulation of the motor cortex in patients with cervical cord lesions. Neurosci Lett 2000; 286:199-202. [PMID: 10832019 DOI: 10.1016/s0304-3940(00)01125-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The silent period following motor evoked potentials in small hand muscles after transcranial magnetic stimulation (TMS) of the human motor cortex is considered to be cortical origin. The authors report three patients with cervical spinal cord lesions who showed loss of the cortical silent period (CSP) after TMS. One patient had traumatic cervical cord injury, and the other two patients had cervical spondylosis. All the patients had cervical cord compression on magnetic resonance imaging. TMS study showed loss of the CSP in both the hand and foot muscles in two patients and only in the foot muscle in one patient. Paired TMS study in one patient with pseudoathetotic hands showed reduced inhibition within the motor cortex. The hand weakness or interrupted sensory afferents might have caused motor cortical reorganization or hyperexcitability, leading to the loss of the CSP.
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Affiliation(s)
- T Shimizu
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, 183-0042, Tokyo, Japan.
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