Focal depression of cortical excitability induced by fatiguing muscle contraction: a transcranial magnetic stimulation study

Wb, McKay; Sm, Tuel; Sherwood, Arthur M.; Stokić, Dobrivoje S.; Mr, Dimitrijević

doi:10.1007/bf00240963

Cited by 112 publications

(95 citation statements)

References 26 publications

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“…The changes in motor cortical excitability described in this study are central in origin as FDI potentials evoked by electrical stimulation of the ulnar nerve were not modi®ed during the exercise and rest periods. In other experiments on the effects of exercise on motor cortical excitability, the role of spinal or peripheral nerve changes have been excluded (Brasil-Neto et al, 1993;McKay et al, 1995;Zanette et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Motor cortex excitability is affected immediately before movement onset (Starr et al, 1988;Reynolds and Ashby, 1999), continues during the course of movement (Ljubisavljevic et al, 1996;Sacco et al, 1997;Aranyi et al, 1998;Tinazzi and Zanette, 1998), and may even persist following movement (Brasil-Neto et al, 1993McKay et al, 1995;Zanette et al, 1995;Bonato et al, 1996;Liepert et al, 1996;Samii et al, 1996Samii et al, , 1997. If movements are continued until`exhaustion' (de®ned by an inability to maintain at least 50% of maximal force), MEPs are reduced for up to 15 min, a phenomenon termed post-exercise depression (Brasil-Neto et al, 1993McKay et al, 1995;Liepert et al, 1996;Samii et al, 1996Samii et al, , 1997.…”

Section: Introductionmentioning

confidence: 99%

“…The neural mechanisms underlying both facilitation and depression of MEPs following exercise are believed to reside within the motor cortex. These changes of motor cortical excitability have been considered relevant for the experience of`fatigue' or well-being accompanying motor activity (Brasil-Neto et al, 1993McKay et al, 1995;Liepert et al, 1996;Samii et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Delayed facilitation of motor cortical excitability following repetitive finger movements

Caramia

Scalise

Gordon

et al. 2000

Clinical Neurophysiology

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Objectives: To de®ne motor cortical excitability changes occurring at various times after non-fatiguing bimanual exercise of the index ®ngers.Methods: Twenty healthy right-handed subjects were studied with transcranial magnetic stimulation (TMS) of the right non-dominant hemisphere. They performed regular (3±4/s) repetitive opening±closing bilateral movements of the index ®nger onto the thumb. Motor evoked potentials (MEPs) of the left ®rst dorsal interosseus (FDI) and rate of the repetitive ®nger movements were determined (1) before exercise, (2) immediately following 3 exercise periods of 30, 60 and 90 s, and (3) over a subsequent 30 min rest period.Results: Rate of movement did not show signi®cant change during any of the exercise periods but did increase signi®cantly when tested after 15 min of rest. MEPs immediately after 30 and 60 s of exercise were facilitated whereas MEPs after 90 s of exercise did not differ from baseline measures. MEP amplitudes were signi®cantly increased after rest of approximately 15 min compared to the baseline MEPs. In contrast, motor potentials evoked by peripheral nerve stimulation were unchanged throughout the experimental test periods.Conclusions: Motor cortical excitability relating to an intrinsic ®nger muscle (FDI) was facilitated beginning 15 min after a brief period of non-forceful, repetitive activity of that muscle. This delayed facilitation of motor cortex after exercise may represent a form of short-term potentiation of motor cortical excitability. q

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Delayed facilitation of motor cortical excitability following repetitive finger movements

Caramia

Scalise

Gordon

et al. 2000

Clinical Neurophysiology

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“…The results of this study showed that post-exercise MEP responses to TMS had decreased in amplitude relative to pre-exercise responses (post-exercise MEP depression). A follow-up study by Brasil-Neto et al (1994) and studies from other groups (McKay et al 1995;Liepert et al 1996;Samii et al 1996a,b) showed that the post-exercise MEP depression is often preceded by an initial short-duration increase in the post-exercise MEP amplitudes relative to pre-exercise responses (post-exercise MEP facilitation). Brasil-Neto et al (1994) demonstrated that MEP amplitudes were reduced to less than half pre-exercise values after an exercise protocol.…”

mentioning

confidence: 97%

“…Samii et al (1996a,b) and Liepert et al (1996) studied the post-exercise changes in the arm and in the small muscles of the hand. McKay et al (1995) were the first group to look at the effects of exercise on TMS-induced responses in the lower limb. Whether or not lower and upper limb muscles respond to exercise in the same manner is still under debate.…”

mentioning

confidence: 99%

Fatigue‐Induced Change in Corticospinal Drive to Back Muscles in Elite Rowers

Fulton

Strutton

McGregor

et al. 2002

Experimental Physiology

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This study examined post‐exercise changes in corticospinal excitability in five ‘elite’ rowers and six non‐rowers. Transcranial magnetic stimulation (TMS) was delivered to the motor cortex and bilateral electromyographic (EMG) recordings were made from erector spinae (ES) muscles at L3/L4 spinal level and from the first dorsal interosseous (FDI) muscle of the dominant hand. Each subject completed two exercise protocols on a rowing ergometer: a light exercise protocol at a sub‐maximal output for 10 min and an intense exercise protocol at maximum output for 1 min. A trial of ten magnetic stimuli was delivered before each of the protocols and, on finishing exercise, further trials of ten stimuli were delivered every 2 min for a 16 min period. Amplitudes of motor‐evoked potentials (MEPs) in each of the three test muscles were measured before exercise and during the recovery period after exercise. The non‐rowers showed a brief facilitation of MEPs in ES 2 min after light and intense exercise that was only present in the elite rowers after intense exercise. In the period 4‐16 min after light exercise, the mean (± S.E.M.) MEP amplitude (relative to pre‐exercise levels) was less depressed in the elite rowers (79.4 ± 2.1%) than in the non‐rowers (60.9 ± 2.5%) in the left ES but not significantly so in the right ES. MEP amplitudes in FDI were significantly larger in the elite rowers, averaging 119.0 ± 3.1% pre‐exercise levels, compared with 101.2 ± 5.8% in the non‐rowers. Pre‐exercise MEP latencies were no different in the two groups. After light exercise MEP latencies became longer in the elite rowers (left ES, 16.1 ± 0.5 ms; right ES, 16.1 ± 0.4 ms; dominant FDI, 23.4 ± 0.2 ms) than in the non‐rowers (left ES, 15.0 ± 0.3 ms; right ES, 15.2 ± 0.3 ms; dominant FDI, 21.5 ± 0.2 ms). There were no differences in MEP depression or latency between elite rowers and non‐rowers after intense exercise. We conclude that the smaller degree of MEP depression in the elite rowers after light exercise reflects less central fatigue within corticospinal control pathways than that seen in the non‐rowers. The longer latency of MEPs seen in the elite rowers may reflect recruitment of more slower‐conducting fatigue‐resistant motor units compared with the non‐rowers. These differences may be because the energy requirements for the non‐rowers during light exercise are closer to their maximum capacity, leading to more fatigue. This notion is supported by the lack of any difference between groups following intense exercise when both groups were working at their own maximum.

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Depression of human electromyographic activity by fatigue of a synergistic muscle

et al. 1997

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In human volunteers, lateral gastrocnemius muscles were stimulated electrically under ischemic conditions so as to produce fatigue. Recordings of electromyographic (EMG) activity were then made from those muscles and simultaneously from untreated medial gastrocnemius muscles during maximal voluntary efforts. In the lateral gastrocnemius the mean amount of EMG activity declined by 52% and was associated with a 35% reduction in the mean amplitude of the M wave (muscle compound action potential) and an insignificant change in M‐wave area. In the medial gastrocnemius the EMG was also diminished, by 29%, but there were no significant changes in M‐wave amplitude or area. The findings in the medial gastrocnemius are consistent with the existence of an inhibitory reflex effect which originates in the fatigued lateral gastrocnemius muscle and serves to depress excitation in motoneurons supplying that muscle and also in those innervating synergists. The inhibitory effect appears to be long‐lasting, in that a significant reduction of the EMG could still be demonstrated 10 min after release of the arterial cuff. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20, 710–717, 1997.

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Focal depression of cortical excitability induced by fatiguing muscle contraction: a transcranial magnetic stimulation study

Cited by 112 publications

References 26 publications

Delayed facilitation of motor cortical excitability following repetitive finger movements

Delayed facilitation of motor cortical excitability following repetitive finger movements

Fatigue‐Induced Change in Corticospinal Drive to Back Muscles in Elite Rowers

Depression of human electromyographic activity by fatigue of a synergistic muscle

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