Determining the Corticospinal and Neuromuscular Responses Following a Warm-Up Protocol

2020 ◽  
Vol 2 (2) ◽  
pp. 1-12
Author(s):  
Rhys Painter ◽  
Alan Pearce ◽  
Mohamad Rostami ◽  
Ashlyn Frazer ◽  
Dawson Kidgell
Keyword(s):  
Heart Rate ◽  
Evoked Potentials ◽  
Neuromuscular Transmission ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Muscle Temperature ◽  
Conduction Time ◽  
Warm Up ◽  
Time To Peak

Background: The effect of warming-up prior to exercise on increased neuromuscular transmission speed remains largely untested. Objective: This study used transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS) to quantify neuromuscular transmission along the corticospinal tract (CST) before and after a warm-up protocol of the elbow flexors. Method: Using a single-group, pre-test-post-test design, 30 participants (20 male; 10 female; mean age 26.3 ± 7.4 years) completed four sets of bicep curls that aimed to increase heart rate (HR) and biceps brachii (BB) muscle temperature by a minimum of 40 beats per minute (bpm) and 1°C, respectively. Single-pulse TMS was applied to the primary motor cortex, and over the cervical and thoracic (C7-T1) areas of the spine to quantify motor evoked potentials (MEPs) and spinal evoked potentials (SEPs), respectively. Central motor conduction time (CMCT) was determined by calculating the difference in latency time of the onset of MEPs and SEPs. Peripheral motor conduction time (PMCT) was calculated following stimuli from Erb’s point to the onset of the maximal compound muscle action potential twitch (MMAX latency). MMAX time to peak twitch was also measured. MMAX amplitude was used to normalize the MEP to quantify corticospinal excitability. Results: Following the warm-up, significant increases in mean heart rate (44.8 ± 11.7 bpm; P < 0.001) and muscle temperature (1.4 ± 0.6°C; P < 0.001) were observed. No changes were seen in corticospinal excitability (P = 0.39), CMCT (P = 0.09), or MMAX latency (P = 0.24). However, MMAX time to peak twitch was significantly reduced (P = 0.003). Conclusion: This study has shown that exercise-based warm-ups improve neuromuscular conduction velocity via thermoregulatory processes that result in the onset of muscle contraction being more rapid, but not as a result of changes in the efficacy of neural transmission along the CST.

scholarly journals Corticospinal excitability of the biceps brachii is shoulder position dependent

2017 ◽  
Vol 118 (6) ◽  
pp. 3242-3251 ◽  
Author(s):  
Brandon Wayne Collins ◽  
Edward W. J. Cadigan ◽  
Lucas Stefanelli ◽  
Duane C. Button
Keyword(s):  
Evoked Potentials ◽  
Maximal Voluntary Contraction ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Voluntary Contraction ◽  
Corticospinal Excitability ◽  
State Dependent ◽  
Shoulder Flexion ◽  
Erb’S Point ◽  
Shoulder Position

The purpose of this study was to examine the effect of shoulder position on corticospinal excitability (CSE) of the biceps brachii during rest and a 10% maximal voluntary contraction (MVC). Participants ( n = 9) completed two experimental sessions with four conditions: 1) rest, 0° shoulder flexion; 2) 10% MVC, 0° shoulder flexion; 3) rest, 90° shoulder flexion; and 4) 10% MVC, 90° shoulder flexion. Transcranial magnetic, transmastoid electrical, and Erb’s point stimulation were used to induce motor-evoked potentials (MEPs), cervicomedullary MEPs (CMEPs), and maximal muscle compound potentials (Mmax), respectively, in the biceps brachii in each condition. At rest, MEP, CMEP, and Mmax amplitudes increased ( P < 0.01) by 509.7 ± 118.3%, 113.3 ± 28.3%, and 155.1 ± 47.9%, respectively, at 90° compared with 0°. At 10% MVC, MEP amplitudes did not differ ( P = 0.08), but CMEP and Mmax amplitudes increased ( P < 0.05) by 32.3 ± 10.5% and 127.9 ± 26.1%, respectively, at 90° compared with 0°. MEP/Mmax increased ( P < 0.01) by 224.0 ± 99.1% at rest and decreased ( P < 0.05) by 51.3 ± 6.7% at 10% MVC at 90° compared with 0°. CMEP/Mmax was not different ( P = 0.22) at rest but decreased ( P < 0.01) at 10% MVC by 33.6 ± 6.1% at 90° compared with 0°. EMG increased ( P < 0.001) by 8.3 ± 2.0% at rest and decreased ( P < 0.001) by 21.4 ± 4.4% at 10% MVC at 90° compared with 0°. In conclusion, CSE of the biceps brachii was dependent on shoulder position, and the pattern of change was altered within the state in which it was measured. The position-dependent changes in Mmax amplitude, EMG, and CSE itself all contribute to the overall change in CSE of the biceps brachii. NEW & NOTEWORTHY We demonstrate that when the shoulder is placed into two common positions for determining elbow flexor force and activation, corticospinal excitability (CSE) of the biceps brachii is both shoulder position and state dependent. At rest, when the shoulder is flexed from 0° to 90°, supraspinal factors predominantly alter CSE, whereas during a slight contraction, spinal factors predominantly alter CSE. Finally, the normalization techniques frequently used by researchers to investigate CSE may under- and overestimate CSE when shoulder position is changed.

scholarly journals Phase and power modulations on the amplitude of TMS-induced motor evoked potentials

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255815
Author(s):  
Lukas Schilberg ◽  
Sanne Ten Oever ◽  
Teresa Schuhmann ◽  
Alexander T. Sack
Keyword(s):  
Evoked Potentials ◽  
Diagnostic Tool ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Beta Phase ◽  
Alpha Phase ◽  
Individual Variability ◽  
Oscillatory Activity ◽  
Alpha Power

The evaluation of transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) promises valuable information about fundamental brain related mechanisms and may serve as a diagnostic tool for clinical monitoring of therapeutic progress or surgery procedures. However, reports about spontaneous fluctuations of MEP amplitudes causing high intra-individual variability have led to increased concerns about the reliability of this measure. One possible cause for high variability of MEPs could be neuronal oscillatory activity, which reflects fluctuations of membrane potentials that systematically increase and decrease the excitability of neuronal networks. Here, we investigate the dependence of MEP amplitude on oscillation power and phase by combining the application of single pulse TMS over the primary motor cortex with concurrent recordings of electromyography and electroencephalography. Our results show that MEP amplitude is correlated to alpha phase, alpha power as well as beta phase. These findings may help explain corticospinal excitability fluctuations by highlighting the modulatory effect of alpha and beta phase on MEPs. In the future, controlling for such a causal relationship may allow for the development of new protocols, improve this method as a (diagnostic) tool and increase the specificity and efficacy of general TMS applications.

Transcranial electrical stimulation through screw electrodes for intraoperative monitoring of motor evoked potentials

2004 ◽  
Vol 100 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Katsushige Watanabe ◽  
Takashi Watanabe ◽  
Akio Takahashi ◽  
Nobuhito Saito ◽  
Masafumi Hirato ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Intraoperative Monitoring ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Transcranial Electrical Stimulation ◽  
Content Type ◽  
Motor Pathways ◽  
Fine Print

✓ The feasibility of high-frequency transcranial electrical stimulation (TES) through screw electrodes placed in the skull was investigated for use in intraoperative monitoring of the motor pathways in patients who are in a state of general anesthesia during cerebral and spinal operations. Motor evoked potentials (MEPs) were elicited by TES with a train of five square-wave pulses (duration 400 µsec, intensity ≤ 200 mA, frequency 500 Hz) delivered through metal screw electrodes placed in the outer table of the skull over the primary motor cortex in 42 patients. Myogenic MEPs to anodal stimulation were recorded from the abductor pollicis brevis (APB) and tibialis anterior (TA) muscles. The mean threshold stimulation intensity was 48 ± 17 mA for the APB muscles, and 112 ± 35 mA for the TA muscles. The electrodes were firmly fixed at the site and were not dislodged by surgical manipulation throughout the operation. No adverse reactions attributable to the TES were observed. Passing current through the screw electrodes stimulates the motor cortex more effectively than conventional methods of TES. The method is safe and inexpensive, and it is convenient for intraoperative monitoring of motor pathways.

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.

scholarly journals Changes in corticospinal excitability during reach adaptation in force fields

2013 ◽  
Vol 109 (1) ◽  
pp. 124-136 ◽  
Author(s):  
Jean-Jacques Orban de Xivry ◽  
Mohammad Ali Ahmadi-Pajouh ◽  
Michelle D. Harran ◽  
Yousef Salimpour ◽  
Reza Shadmehr
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Neural Basis ◽  
Key Factor ◽  
Gradual Group ◽  
Specific Increase ◽  
Stimulation Of

Both abrupt and gradually imposed perturbations produce adaptive changes in motor output, but the neural basis of adaptation may be distinct. Here, we measured the state of the primary motor cortex (M1) and the corticospinal network during adaptation by measuring motor-evoked potentials (MEPs) before reach onset using transcranial magnetic stimulation of M1. Subjects reached in a force field in a schedule in which the field was introduced either abruptly or gradually over many trials. In both groups, by end of the training, muscles that countered the perturbation in a given direction increased their activity during the reach (labeled as the on direction for each muscle). In the abrupt group, in the period before the reach toward the on direction, MEPs in these muscles also increased, suggesting a direction-specific increase in the excitability of the corticospinal network. However, in the gradual group, these MEP changes were missing. After training, there was a period of washout. The MEPs did not return to baseline. Rather, in the abrupt group, off direction MEPs increased to match on direction MEPs. Therefore, we observed changes in corticospinal excitability in the abrupt but not gradual condition. Abrupt training includes the repetition of motor commands, and repetition may be the key factor that produces this plasticity. Furthermore, washout did not return MEPs to baseline, suggesting that washout engaged a new network that masked but did not erase the effects of previous adaptation. Abrupt but not gradual training appears to induce changes in M1 and/or corticospinal networks.

Automatic Recruitment of the Motor System by Undetected Graspable Objects: A Motor-evoked Potential Study

2017 ◽  
Vol 29 (11) ◽  
pp. 1918-1931 ◽  
Author(s):  
Nicolas A. McNair ◽  
Ashleigh D. Behrens ◽  
Irina M. Harris
Keyword(s):  
Evoked Potentials ◽  
Visual Processing ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Direct Evidence ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Motor Action ◽  
Motor Pathway ◽  
The Right

Previous behavioral and neuroimaging studies have suggested that the motor properties associated with graspable objects may be automatically accessed when people passively view these objects. We directly tested this by measuring the excitability of the motor pathway when participants viewed pictures of graspable objects that were presented during the attentional blink (AB), when items frequently go undetected. Participants had to identify two briefly presented objects separated by either a short or long SOA. Motor-evoked potentials were measured from the right hand in response to a single TMS pulse delivered over the left primary motor cortex 250 msec after the onset of the second target. Behavioral results showed poorer identification of objects at short SOA compared with long SOA, consistent with an AB, which did not differ between graspable and nongraspable objects. However, motor-evoked potentials measured during the AB were significantly higher for graspable objects than for nongraspable objects, irrespective of whether the object was successfully identified or undetected. This provides direct evidence that the motor system is automatically activated during visual processing of objects that afford a motor action.

scholarly journals The Excitability of Ipsilateral Motor Evoked Potentials Is Not Task-specific and Spatially Distinct From the Contralateral Motor Hotspot

2022 ◽  
Author(s):  
Nelly Seusing ◽  
Sebastian Strauss ◽  
Robert Fleischmann ◽  
Christina Nafz ◽  
Sergiu Groppa ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Primary Motor Cortex ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Elbow Flexion ◽  
Motor Pathways ◽  
Task Dependence ◽  
Flexion Extension ◽  
Voluntary Contractions

Abstract ObjectiveThe role of ipsilateral descending motor pathways in voluntary movement of humans is still a matter of debate. Few studies have examined the task dependent modulation of ipsilateral motor evoked potentials (iMEPs). Here, we determined the location of upper limb biceps brachii (BB) representation within the ipsilateral primary motor cortex. MethodsMR-navigated transcranial magnetic stimulation mapping of the dominant hemisphere was undertaken with twenty healthy participants who made tonic unilateral, bilateral homologous or bilateral antagonistic elbow flexion-extension voluntary contractions. Map center of gravity (CoG) and area for each BB were obtained. ResultsThe map CoG of the ipsilateral BB was located more anterior-laterally than those of the contralateral BB within the primary motor cortex. However different tasks had no effect on either the iMEP CoG location or the size. ConclusionOur data suggests that ipsilateral and contralateral MEP might originate in distinct adjacent neural populations in the primary motor cortex, independent of task dependence.

Corticospinal Excitability of the Ankle Extensor Muscles Is Enhanced in Ballet Dancers

2014 ◽  
Vol 29 (3) ◽  
pp. 144-149 ◽  
Author(s):  
Sakiko Saito ◽  
Hiroki Obata ◽  
Takashi Endoh ◽  
Mayumi Kuno-Mizumura ◽  
Kimitaka Nakazawa
Keyword(s):  
Evoked Potentials ◽  
Soleus Muscle ◽  
Motor Evoked Potentials ◽  
Regression Line ◽  
Corticospinal Excitability ◽  
Control Group ◽  
Electromyographic Activity ◽  
Plantar Flexors ◽  
Ballet Dancers

We tested the corticospinal excitability of the soleus muscle in ballet dancers to clarify whether the presumed long-term repetition of the specific plantarflexion results in changes of excitability in this neural pathway. We compared motor evoked potentials of the soleus muscle at rest and during isometric contraction of the plantar flexors in dancers and nondancers. The amplitudes of motor evoked potentials elicited by transcranial magnetic stimulation during contraction were examined against the background electromyographic activity. A regression line was calculated for each subject. Results showed that the slope of the regression line is significantly greater in the dancer group than in the control group, suggesting that the corticospinal tract of ballet dancers has adapted to long-term repetition of plantarflexion in daily ballet training.

Motor evoked potentials in clinically isolated syndrome suggestive of multiple sclerosis

2009 ◽  
Vol 15 (3) ◽  
pp. 355-362 ◽  
Author(s):  
A Rico ◽  
B Audoin ◽  
J Franques ◽  
A Eusebio ◽  
F Reuter ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Evoked Potentials ◽  
Amplitude Ratio ◽  
Motor Evoked Potentials ◽  
Clinically Isolated Syndrome ◽  
Conduction Time ◽  
Motor Pathway ◽  
Clinical Sensitivity ◽  
Conduction Failure ◽  
Stimulation Technique

The aim of the present study was to determine the sensitivity and the profile of motor evoked potentials (MEP) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). We measured the central motor conduction time (CMCT), amplitude ratio (AR), and surface ratio (SR) in tibialis anterior and first dorsal interosseous muscles in 22 patients with CIS. In 12 patients, the triple stimulation technique (TST) was also performed. AR was abnormal in 50% of patients, CMCT in 18% of patients, and TST in 25% of patients. AR had the highest sub-clinical sensitivity and the best positive predictive value. In the absence of clinical pyramidal signs, an early AR decrease seems to result from demyelination inducing excessive temporal dispersion of the MEP, while in territories with clinical pyramidal signs, it seems to result from conduction failure, which suggests that clinical pyramidal signs may be attributable to conduction failure. This study demonstrates that MEP, especially the AR, is sensitive to motor pathway dysfunction right from the early stages of MS.

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