scholarly journals Transcranial stimulation excites virtually all motor neurons supplying the target muscle. A demonstration and a method improving the study of motor evoked potentials

Brain ◽  
1998 ◽  
Vol 121 (3) ◽  
pp. 437-450 ◽  
Author(s):  
M. Magistris
Keyword(s):  
Evoked Potentials ◽  
Motor Neurons ◽  
Motor Evoked Potentials ◽  
Transcranial Stimulation

The size of motor-evoked potentials: influencing parameters and quantification

2012 ◽  
Author(s):  
Kai M. Rösler ◽  
Michel R. Magistris
Keyword(s):  
Evoked Potentials ◽  
Motor Neurons ◽  
Healthy Subjects ◽  
Motor Evoked Potentials ◽  
Conduction Block ◽  
Phase Cancellation ◽  
Pathological Conditions ◽  
The Central Nervous System ◽  
Stimulation Technique ◽  
Triple Stimulation Technique

This article discusses parameters influencing the size of motor-evoked potentials (MEPs) in normal and pathological conditions, and the methods of meaningful quantification of the MEPs. MEPs are widely used to study the physiology of corticospinal conduction in healthy subjects and in patients with diseases of the central nervous system. The characteristics of MEP size are, stimulus intensity, coil positioning, and facilitation. MEPs show variability in size and shape from one stimulus to the next, even if the stimulus parameters are kept constant. This article describes the triple stimulation technique (TST), which was developed to eliminate the effects of phase cancellation from the MEPs, to allow for a better quantification. Pathological conditions may modify the parameters discussed in the article and influence the size of the MEPs by lesions of motor neurons or of their axons, central conduction velocity slowing, or conduction block.

Motor Evoked Potentials from Transcranial Stimulation of the Motor Cortex in Humans

Neurosurgery ◽  
1984 ◽  
Vol 15 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Walter J. Levy ◽  
Donald H. York ◽  
Michael McCaffrey ◽  
Fred Tanzer
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Sensory Modality ◽  
Motor Evoked Potential ◽  
Transcranial Stimulation ◽  
Direct Stimulation ◽  
Stimulation Of

Abstract Electrical monitoring of the motor system offers the potential for the detection of injury, the diagnosis of disease, the evaluation of treatment, and the prediction of recovery from damage. Existing evoked potentials monitor one or another sensory modality, but no generally usable motor monitor exists. We have reported a motor evoked potential using direct stimulation of the spinal cord over the motor tracts in cats and in humans. To achieve a less invasive monitor, we used transcranial stimulation over the motor cortex in the cat, thus stimulating the motor cortex. We report here the initial application of this method to humans. A plate electrode over the motor cortex on the scalp and a second electrode on the palate direct a mild current through the motor cortex which will activate the motor pathways. This signal can be recorded over the spinal cord. It can elicit contralateral peripheral nerve and electromyographic signals in the limbs or movements when the appropriate stimulation parameters are used. In clinical use to date, this has been more reliable than the somatosensory evoked potential in predicting motor function in patients where the two tests differed. It offers a number of possibilities for the development of valuable brain and spinal cord monitoring techinques, but requires further animal studies and clinical experience. Studies to date have not demonstrated adverse effects, but evaluation is continuing.

scholarly journals Statistical Model of Motor Evoked Potentials for Simulation of Transcranial Magnetic and Electric Stimulation

2018 ◽  
Author(s):  
Stefan M. Goetz ◽  
S. M. Madhi Alavi ◽  
Zhi-De Deng ◽  
Angel V. Peterchev
Keyword(s):  
Statistical Model ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Transcranial Stimulation ◽  
Large Variability ◽  
Dose Individualization ◽  
Estimation Algorithms ◽  
Amplitude Data ◽  
Virtual Population ◽  
Characteristic Features

AbstractMotor evoked potentials (MEPs) are widely used for biomarkers and dose individualization in transcranial stimulation. The large variability of MEPs requires sophisticated methods of analysis to extract information fast and correctly. However, models of MEPs that represent their characteristic features are lacking. This work presents a statistical model that can simulate long sequences of individualized MEP amplitude data with properties matching experimental observations. The MEP model includes three sources of trial-to-trial variability to mimic excitability fluctuations, variability in the neural and muscular pathways, and physiological and measurement noise. It also generates virtual human subject data from statistics of population variability. All parameters are extracted as statistical distributions from experimental data from the literature. The model exhibits previously described features, such as stimulusintensity-dependent MEP amplitude distributions, including bimodal ones. The model can generate long sequences of test data for individual subjects with specified parameters or for subjects from a virtual population. The presented MEP model is the most detailed to date and can be used for the development and implementation of dosing and biomarker estimation algorithms for transcranial stimulation.

Motor Evoked Potentials from Transcranial Stimulation of the Motor Cortex in Cats

Neurosurgery ◽  
1984 ◽  
Vol 15 (2) ◽  
pp. 214-227 ◽  
Author(s):  
Walter J. Levy ◽  
Michael McCaffrey ◽  
Donald H. York ◽  
Fred Tanzer
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Transcranial Stimulation ◽  
Stimulation Of
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