Facilitation of magnetic motor evoked potentials during the mixed nerve silent period

1995 ◽  
Vol 18 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
Michael S. Young ◽  
William J. Triggs ◽  
Gabriella Gerstle
Keyword(s):  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Mixed Nerve

scholarly journals Transspinal stimulation decreases corticospinal excitability and alters the function of spinal locomotor networks

2019 ◽  
Vol 122 (6) ◽  
pp. 2331-2343 ◽  
Author(s):  
Timothy S. Pulverenti ◽  
Md. Anamul Islam ◽  
Ola Alsalman ◽  
Lynda M. Murray ◽  
Noam Y. Harel ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Surface Emg ◽  
Corticospinal Excitability ◽  
Emg Activity ◽  
Step Cycle ◽  
Healthy Humans ◽  
Descending Volleys ◽  
Period Duration

Locomotion requires the continuous integration of descending motor commands and sensory inputs from the legs by spinal central pattern generator circuits. Modulation of spinal neural circuits by transspinal stimulation is well documented, but how transspinal stimulation affects corticospinal excitability during walking in humans remains elusive. We measured the motor evoked potentials (MEPs) at multiple phases of the step cycle conditioned with transspinal stimulation delivered at sub- and suprathreshold intensities of the spinally mediated transspinal evoked potential (TEP). Transspinal stimulation was delivered before or after transcranial magnetic stimulation during which summation between MEP and TEP responses in the surface EMG was absent or present. Relationships between MEP amplitude and background EMG activity, silent period duration, and phase-dependent EMG amplitude modulation during and after stimulation were also determined. Ankle flexor and extensor MEPs were depressed by suprathreshold transspinal stimulation when descending volleys were timed to interact with transspinal stimulation-induced motoneuron depolarization at the spinal cord. MEP depression coincided with decreased MEP gain, unaltered MEP threshold, and unaltered silent period duration. Locomotor EMG activity of bilateral knee and ankle muscles was significantly depressed during the step at which transspinal stimulation was delivered but fully recovered at the subsequent step. The results support a model in which MEP depression by transspinal stimulation occurs via subcortical or spinal mechanisms. Transspinal stimulation disrupts the locomotor output of flexor and extensor motoneurons initially, but the intact nervous system has the ability to rapidly overcome this pronounced locomotor adaptation. In conclusion, transspinal stimulation directly affects spinal locomotor centers in healthy humans. NEW & NOTEWORTHY Lumbar transspinal stimulation decreases ankle flexor and extensor motor evoked potentials (MEPs) during walking. The MEP depression coincides with decreased MEP gain, unaltered MEP threshold changes, and unaltered silent period duration. These findings indicate that MEP depression is subcortical or spinal in origin. Healthy subjects could rapidly overcome the pronounced depression of muscle activity during the step at which transspinal stimulation was delivered. Thus, transspinal stimulation directly affects the function of spinal locomotor networks in healthy humans.

Cortical silent period and motor evoked potentials in patients with multiple sclerosis

2003 ◽  
Vol 105 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Cengiz Tataroglu ◽  
Ahmet Genc ◽  
Egemen Idiman ◽  
Raif Cakmur ◽  
Fethi Idiman
Keyword(s):  
Multiple Sclerosis ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Cortical Silent Period

Evoked potentials in a subject with a large-fibre sensory neuropathy below the neck

1995 ◽  
Vol 73 (2) ◽  
pp. 234-245 ◽  
Author(s):  
J. D. Cole ◽  
W. L. Merton ◽  
G. Barrett ◽  
H. A. Katifi ◽  
R.-D. Treede
Keyword(s):  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Sensory Neuropathy ◽  
Middle Finger ◽  
Passive Movement ◽  
Position Sensitivity ◽  
Large Fibre ◽  
The Subject ◽  
Imagined Movement

The results from experiments in various modalities of evoked potentials are described in a subject with a complete large peripheral neuropathy below the neck. He has no tactile or position sensitivity below that level, but has retained fatigue, pain, and temperature sensation. Percutaneous electrical stimulation of peripheral nerves led to scalp recorded evoked potentials with thresholds and propagation velocities compatible with conduction along A-δ peripheral pathways. CO2 laser evoked potentials were similar to those seen in controls, further support for intact A-δ peripheral fibres. Movement-related cortical potentials (MRCPs) were recorded associated with active and passive movement of the middle finger. The former were normal, evidence that the termination of the MRCP is not dependent on peripheral feedback. By comparing passive MRCPs between controls and the subject it was possible to establish which parts of the potentials are visual and which are proprioceptive and to gain evidence of central reorganisation in the subject. Magnetic brain stimulation was used to show that the subject did not perceive induced movement, had a normal centrally originating silent period, and could focus his attention during real and imagined movement of the finger more successfully than could normal controls.Key words: sensory and motor evoked potentials, sensory neuropathy.

scholarly journals Influence of iTBS on the Acute Neuroplastic Change After BCI Training

2021 ◽  
Vol 15 ◽  
Author(s):  
Qian Ding ◽  
Tuo Lin ◽  
Manfeng Wu ◽  
Wenqing Yang ◽  
Wanqi Li ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Functional Connectivity ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Single Pulse ◽  
Functional Near Infrared Spectroscopy ◽  
Significant Difference

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.

Task-Dependent Effects on Motor-Evoked Potentials and on the Following Silent Period

1999 ◽  
Vol 16 (6) ◽  
pp. 556 ◽  
Author(s):  
Johannes Mathis ◽  
Dominique de Quervain ◽  
Christian W. Hess
Keyword(s):  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Silent Period
Sign in / Sign up

Export Citation Format

Share Document