Effect of fatiguing maximal voluntary contraction on excitatory and inhibitory responses elicited by transcranial magnetic motor cortex stimulation

Wb, McKay; Stokić, Dobrivoje S.; Sherwood, Arthur M.; Vrbová, Gerta; Mr, Dimitrijević

doi:10.1002/mus.880190803

Cited by 76 publications

(63 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increased duration of the cSP work during an effortful fatiguing contraction was an expected finding, since it has been demonstrated previously (McKay et al 1996;Taylor et al 1996Taylor et al , 2000Sacco et al 1997;Taylor and Gandevia 2001). Here, we observed an effort-related increase in the cSP also in the mirroring muscle (Table 1, Fig.…”

Section: Discussionsupporting

confidence: 89%

See 1 more Smart Citation

Effort-induced mirror movements

2002

View full text Add to dashboard Cite

During sustained, fatiguing maximal voluntary contraction of muscles of one hand, muscles of the other hand gradually become activated also. Such effortinduced mirror movements indicate a decreased ability of the central nervous system (CNS) to selectively control individual muscles. We studied whether altered transcallosal inhibition (TCI) contributed to this phenomenon. TCI was determined in ten healthy subjects by measuring the ipsilateral silent period (iSP) and the contralateral silent period (cSP) during a sustained contraction of the abductor digiti minimi, induced by focal unihemispheric ipsilateral transcranial magnetic stimulation. Mirror movements occurred in all subjects in response to the effort. There was a bilateral increase in cSPs and a parallel increase in the iSP in the contralateral working muscle. In contrast, the iSP in the mirroring muscle remained unchanged, explained by a balance of increased crossed pyramidal inhibition (cSP) and decreased transcallosal inhibition. In finely tuned unimanual movements, mirroring activity of the contralateral hand is suppressed by TCI originating in the working hemisphere. During sustained, effortful contractions, the outflow of the contralateral hemisphere is increased due to reduced TCI. Effort-induced mirror contractions are thus the result of disinhibition of contralateral crossed projections rather than disinhibition of ipsilateral uncrossed pathways.

show abstract

Section: Discussionsupporting

confidence: 89%

“…The cSP is considered an indicator of inhibitory mechanisms related to fatigue during a sustained contraction (McKay et al 1996;Taylor et al 1996;Sacco et al 1997). …”

Section: Experimental Protocolmentioning

confidence: 99%

Effort-induced mirror movements

2002

View full text Add to dashboard Cite

show abstract

“…An increasing amplitude of the superimposed twitch evoked by TMS indicates that voluntary output from the motor cortex becomes suboptimal to drive the motor units to generate maximal force from the muscle. At the same time, the size of the motor evoked potential increases (19,34,50,51), partly due to an increase in motor cortical excitability (51,52), and the silent period lengthens, suggesting an increase in intracortical inhibition (e.g., Refs. 19,34,50).…”

Section: Sustained Mvcmentioning

confidence: 99%

“…At the same time, the size of the motor evoked potential increases (19,34,50,51), partly due to an increase in motor cortical excitability (51,52), and the silent period lengthens, suggesting an increase in intracortical inhibition (e.g., Refs. 19,34,50). However, under some conditions, the changes in EMG responses to TMS can be dissociated from impairment of voluntary activation and this suggests that they are not causally related.…”

Section: Sustained Mvcmentioning

confidence: 99%

Use of motor cortex stimulation to measure simultaneously the changes in dynamic muscle properties and voluntary activation in human muscles

Todd¹,

Taylor²,

Butler³

et al. 2007

Journal of Applied Physiology

View full text Add to dashboard Cite

RB, Gandevia SC. Use of motor cortex stimulation to measure simultaneously the changes in dynamic muscle properties and voluntary activation in human muscles. J Appl Physiol 102: 1756 -1766, 2007. First published January 1, 2007; doi:10.1152/japplphysiol.00962.2006.-Force responses to transcranial magnetic stimulation of motor cortex (TMS) during exercise provide information about voluntary activation and contractile properties of the muscle. Here, TMS-generated twitches and muscle relaxation during the TMS-evoked silent period were measured in fresh, heated, and fatigued muscle. Subjects performed isometric contractions of elbow flexors in two studies. Torque and EMG were recorded from elbow flexor and extensor muscles. One study (n ϭ 6) measured muscle contraction times and relaxation rates during brief maximal and submaximal contractions in fresh and fatigued muscle. Another study (n ϭ 7) aimed to 1) assess the reproducibility of muscle contractile properties during brief voluntary contractions in fresh muscle, 2) validate the technique for contractile properties in passively heated muscle, and 3) apply the technique to study contractile properties during sustained maximal voluntary contractions. In both studies, muscle contractile properties during voluntary contractions were compared with the resting twitch evoked by motor nerve stimulation. Measurement of muscle contractile properties during voluntary contractions is reproducible in fresh muscle and reveals faster and slower muscle relaxation rates in heated and fatigued muscle, respectively. The technique is more sensitive to altered muscle state than the traditional motor nerve resting twitch. Use of TMS during sustained maximal contractions reveals slowing of muscle contraction and relaxation with different time courses and a decline in voluntary activation. Voluntary output from the motor cortex becomes insufficient to maintain complete activation of muscle, although slowing of muscle contraction and relaxation indicates that lower motor unit firing rates are required for fusion of force.transcranial magnetic stimulation; muscle relaxation rate; fatigue; hypothermia IN HUMANS, THE CONTRACTILE properties of muscle are usually assessed by measurement of the resting twitch evoked by a supramaximal stimulus to a muscle's motor nerve. The stimulus is delivered within seconds after a voluntary contraction when the muscle is still potentiated by prior activity (e.g., Refs. 5, 43). The characteristics of the resting twitch provide information about the speed of muscle contraction and relaxation and about the force output from the muscle. However, a major limitation of this technique is that it only reveals the state of the muscle at rest and not during voluntary contractions when muscle properties can be changing rapidly. For example, the potentiation and twitch dynamics in contracting muscle are likely to differ from relaxation conditioned by prior activity. To overcome this limitation, we recently proposed a new technique whereby changes in the contractile ...

show abstract

“…reduced firing probability, of motoneurons and might thus contribute to the development of central fatigue (Butler et al 2007). Immediately following fatiguing exercise, MEPs during relaxation have been reported to be reduced (Brasil-Neto et al 1993;McKay et al 1995;Zanette et al 1995;Liepert et al 1996;Samii et al 1996;Maruyama et al 2006) and CSP lengthened (McKay et al 1996).…”

Section: Hilty and Othersmentioning

confidence: 99%

Spinal opioid receptor-sensitive muscle afferents contribute to the fatigue-induced increase in intracortical inhibition in healthy humans

Hilty

Lutz

Maurer

et al. 2011

Experimental Physiology

View full text Add to dashboard Cite

We investigated the influence of spinal opioid receptor-sensitive muscle afferents on cortical changes following fatiguing unilateral knee-extensor exercise. On separate days, seven subjects performed an identical five sets of intermittent isometric right-quadriceps contractions, each consisting of eight submaximal contractions [63 ± 7% maximal voluntary contraction (MVC)] and one MVC. The exercise was performed following either lumbar interspinous saline injection or lumbar intrathecal fentanyl injection blocking the central projection of spinal opioid receptor-sensitive lower limb muscle afferents. To quantify exercise-induced peripheral fatigue, quadriceps twitch force (Q tw,pot ) was assessed via supramaximal magnetic femoral nerve stimulation before and after exercise. Motor evoked potentials and cortical silent periods (CSPs) were evaluated via transcranial magnetic stimulation of the motor cortex during a 3% MVC pre-activation period immediately following exercise. End-exercise quadriceps fatigue was significant and similar in both conditions ( Q tw,pot −35 and −39% for placebo and fentanyl, respectively; P = 0.38). Immediately following exercise on both days, motor evoked potentials were similar to those obtained prior to exercise. Compared with pre-exercise baseline, CSP in the placebo trial was 21 ± 5% longer postexercise (P < 0.01). In contrast, CSP following the fentanyl trial was not significantly prolonged compared with the pre-exercise baseline (6 ± 4%). Our findings suggest that the central effects of spinal opioid receptor-sensitive muscle afferents might facilitate the fatigue-induced increase in CSP. Furthermore, since the CSP is thought to reflect inhibitory intracortical interneuron activity, which may contribute to central fatigue, our findings imply that spinal opioid receptor-sensitive muscle afferents might influence central fatigue by facilitating intracortical inhibition.

show abstract

Effect of fatiguing maximal voluntary contraction on excitatory and inhibitory responses elicited by transcranial magnetic motor cortex stimulation

Cited by 76 publications

References 40 publications

Effort-induced mirror movements

Effort-induced mirror movements

Use of motor cortex stimulation to measure simultaneously the changes in dynamic muscle properties and voluntary activation in human muscles

Spinal opioid receptor-sensitive muscle afferents contribute to the fatigue-induced increase in intracortical inhibition in healthy humans

Contact Info

Product

Resources

About