Non-invasive magnetic stimulation of human motor cortex
About: This article is published in The Lancet.The article was published on 1985-05-11. It has received 3880 citations till now. The article focuses on the topics: Motor cortex & Sensory system.
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TL;DR: Evidence for "central" fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it.
Abstract: Muscle fatigue is an exercise-induced reduction in maximal voluntary muscle force. It may arise not only because of peripheral changes at the level of the muscle, but also because the central nervous system fails to drive the motoneurons adequately. Evidence for “central” fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it. Much data suggest that voluntary activation of human motoneurons and muscle fibers is suboptimal and thus maximal voluntary force is commonly less than true maximal force. Hence, maximal voluntary strength can often be below true maximal muscle force. The technique of twitch interpolation has helped to reveal the changes in drive to motoneurons during fatigue. Voluntary activation usually diminishes during maximal voluntary isometric tasks, that is central fatigue develops, and motor unit firing rates decline. Transcranial magnetic stimulation over the motor cortex during fatiguing exercise has revealed focal cha...
3,200 citations
TL;DR: This year's jurors included A.M.
2,945 citations
TL;DR: It is concluded that in humans there is a system matching action observation and execution that resembles the one recently described in the monkey.
Abstract: 1. We stimulated the motor cortex of normal subjects (transcranial magnetic stimulation) while they 1) observed an experimenter grasping 3D-objects, 2) looked at the same 3D-objects, 3) observed an experimenter tracing geometrical figures in the air with his arm, and 4) detected the dimming of a light. Motor evoked potentials (MEPs) were recorded from hand muscles. 2. We found that MEPs significantly increased during the conditions in which subjects observed movements. The MEP pattern reflected the pattern of muscle activity recorded when the subjects executed the observed actions. 3. We conclude that in humans there is a system matching action observation and execution. This system resembles the one recently described in the monkey.
2,195 citations
Cites background from "Non-invasive magnetic stimulation o..."
...The assumption underlying the experiment was that, if the observation of a movement activates the premotor cortex also in man, this activation should induce an enhancement of motor evoked potentials (MEPs) elicited by the magnetic stimulation of the motor cortex (see Barker et al. 1985)....
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The Catholic University of America1, Royal Prince Alfred Hospital2, University of Toronto3, Centre for Addiction and Mental Health4, Università Campus Bio-Medico5, University of Eastern Finland6, Monash University7, Medical University of South Carolina8, Paris 12 Val de Marne University9, University of Regensburg10, University of Brescia11, University of Göttingen12, Beth Israel Deaconess Medical Center13, University of Siena14, University College London15, Copenhagen University Hospital16, Fukushima Medical University17, University of Tübingen18
TL;DR: These guidelines provide an up-date of previous IFCN report on “Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application” and include some recent extensions and developments.
1,850 citations
Cites background or methods from "Non-invasive magnetic stimulation o..."
...However, the fields of application declined rapidly with the introduction of transcranial magnetic stimulation (TMS) in 1985 by Barker et al. (1985) because high-voltage TES is uncomfortable....
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...After the introduction of TMS by Barker et al. (1985), the first clinical use of this new technique was to estimate the CMCT in humans by recording MEPs to stimulation of the motor cortex and spinal roots (Table 4)....
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Paris 12 Val de Marne University1, French Institute of Health and Medical Research2, University of Göttingen3, Ghent University4, University Hospital of Lausanne5, University of Lisbon6, university of lille7, Università Campus Bio-Medico8, University of Belgrade9, University of Hamburg10, Turku University Hospital11, Aristotle University of Thessaloniki12, University of Regensburg13, University of Bern14, Ludwig Maximilian University of Munich15, University of Siena16, The Catholic University of America17, University College London18, University of Ulm19, Copenhagen University Hospital20, University of Oxford21, University of Barcelona22, University of Tübingen23
TL;DR: There is a sufficient body of evidence to accept with level A (definite efficacy) the analgesic effect of high-frequency rTMS of the primary motor cortex (M1) contralateral to the pain and the antidepressant effect of HF-rT MS of the left dorsolateral prefrontal cortex (DLPFC).
1,554 citations
Cites background from "Non-invasive magnetic stimulation o..."
...One hundred and fifty years later, Barker et al. (1985) proposed the first magnetic stimulator designed to stimulate the human brain transcranially, providing the prerequisite for subsequent clinical use of transcranial magnetic stimulation (TMS) (Barker, 1999)....
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References
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TL;DR: Brief high-voltage electrical shocks from a special low-output-resistance stimulator, delivered through electrodes on the skin, can excite human muscle directly (not by way of the nerves) and can also excite the motor cortex, the visual cortex, and the spinal cord.
285 citations
TL;DR: Preliminary results are presented which suggest that the method of stimulating nerves using a time-varying magnetic field has the advantages over conventional electrical stimulation of being painless, and free of charge-storage artefact.
Abstract: THIS note describes a method of stimulating nerves using a time-varying magnetic field. Preliminary results are presented which suggest that the method has the advantages over conventional electrical stimulation of being painless, and free of charge-storage artefact. It is well known that nerve trunks are stimulated by externally applied voltage or current impulses, and this is regularly used as both a diagnostic and therapeutic aid (BUCHTAL and ROSENFALCK, 1966). Unfortunately this method of electrical stimulation has some drawbacks which cannot readily be overcome non-invasively. When a stimulus is applied via surface electrodes, most of the current will flow between the electrodes through the top living layers of the skin. If the nerve is relatively superficial, a significant proportion of the applied current will flow in the vicinity of the nerve, thereby stimulating it. However, the current cannot simply be increased to reach deep lying nerves, because it would be painful. The nerve fibres which convey pain impulses to the brain have endings in the skin and because the current density here is high, they will be stimulated despite their lower absolute sensitivity to stimulation than other fibres. In addition, high current densities near the surface of the skin can cause tissue damage. The use of a time-varying magnetic field to induce a current in the vicinity of a nerve, and thereby stimulate it, has been tried as a way of overcoming these difficulties by a number of authors, e.g. OBERG (1973), MAASS and ASA (1970), who used invasive methods. HALLGREN (1973) has described a circuit for a non-invasive magnetic stimulator, but did not give examples of the results obtained, or details of the position and current of the stimulation coil. The prototype 'magnetic stimulator ' used is a flat circular coil carrying a time-varying current to produce an
186 citations
TL;DR: The technique of scalp stimulation of the motor cortex was used to demonstrate abnormalities in the corticomotoneuron pathway in multiple sclerosis, and changes may be seen even in patients with little clinical evidence of cortIComot oneuron deficit.
146 citations
TL;DR: It is concluded that the excitability and conduction velocity of the corticospinal motor pathways are normal in Parkinson's disease, even though patients were unable to execute fast thumb flexion movements voluntarily when OFF.
Abstract: Voluntary movements in Parkinson's disease are initiated and executed slowly1,2. It is assumed that the motor cortex and its output pathway are intact and that bradykinesia is due to abnormal motor commands delivered to a normal corticospinal system. We have tested this assumption using electrical stimulation of the motor cortex through the scalp in three patients with severe Parkinson's disease, studied during fluctuations from relatively normal mobility when receiving drugs (ON) to severe bradykinesia when not receiving drugs (OFF). Thresholds and latencies for motor cortex stimulation to excite thumb flexor muscles and the resulting fast mechanical responses were the same in both ON and OFF conditions, even though the patients were unable to execute fast thumb flexion movements voluntarily when OFF. We conclude that the excitability and conduction velocity of the corticospinal motor pathways are normal in Parkinson's disease.
109 citations