Testing the excitability of human motoneurons

McNeil, Chris J.; Butler, Jane E.; Taylor, Janet L.; Gandevia, Simon C.

doi:10.3389/fnhum.2013.00152

Cited by 183 publications

(200 citation statements)

References 86 publications

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“…demonstrated by decreased ICF) and increased motoneuronal excitability to offset cortical hypoexcitability, leading to increased SOL MEP amplitude. While in the future the use of corticospinal tract stimulation (Giesebrecht et al 2010;McNeil et al 2013) in conjunction with TMS would enable the determination of differential effects of vibration on both cortical and motoneuronal excitability, previous reports do not support differential vibration effects at the spinal and cortical levels. For instance, both unchanged F-waves (a means of assessing motoneuronal excitability) during vibration (Rollnik et al 2001) and unaffected postsynaptic excitability of SOL motoneurons during 25-Hz SOL vibration (Abbruzzese et al 1997) have been reported.…”

Section: Discussionmentioning

confidence: 99%

Modulation of soleus corticospinal excitability during Achilles tendon vibration

et al. 2015

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Soleus (SOL) corticospinal excitability has been reported to increase during Achilles tendon vibration. The aim of the present study was to further investigate SOL corticospinal excitability and elucidate the changes to intracortical mechanisms during Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the SOL by transcranial magnetic stimulation (TMS) of the corresponding motor cortical area of the leg with and without 50-Hz Achilles tendon vibration. SOL input-output curves were determined. Paired-pulse protocols were also performed to investigate short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) by conditioning test TMS pulses with sub-threshold TMS pulses at inter-stimulus intervals of 3 and 13 ms, respectively. During Achilles tendon vibration, motor threshold was lower than in the control condition (43 ± 13 vs. 49 ± 11 % of maximal stimulator output; p = 0.008). Input-output curves were also influenced by vibration, i.e. there was increased maximal MEP amplitude (0.694 ± 0.347 vs. 0.268 ± 0.167 mV; p < 0.001), decreased TMS intensity to elicit a MEP of half the maximal MEP amplitude (100 ± 13 vs. 109 ± 9 % motor threshold; p = 0.009) and a strong tendency for decreased slope constant (0.076 ± 0.04 vs. 0.117 ± 0.04; p = 0.068). Vibration reduced ICF (98 ± 61 vs. 170 ± 105 % of test MEP amplitude; p = 0.05), but had no effect on SICI (53 ± 26 vs. 48 ± 22 % of test MEP amplitude; p = 0.68). The present results further document the increased vibration-induced corticospinal excitability in the soleus muscle and suggest that this increase is not mediated by changes in SICI or ICF.

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Section: Discussionmentioning

confidence: 99%

Modulation of soleus corticospinal excitability during Achilles tendon vibration

et al. 2015

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“…24,25 In the current study, to further explore the role of these parameters in the diagnosis of RLS/WED, we aimed to assess the accuracy and compare the diagnostic values of each of these measures in a group of patients affected by primary RLS/ WED.…”

Section: Brief Summarymentioning

confidence: 99%

F-Wave Duration as a Specific and Sensitive Tool for the Diagnosis of Restless Legs Syndrome/Willis-Ekbom Disease

Congiu

Fantini

Milioli

et al. 2017

Journal of Clinical Sleep Medicine

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Study Objectives: Restless legs syndrome, also known as Willis-Ekbom disease (RLS/WED), is a frequent condition, though its pathophysiology is not completely understood. The diagnosis of RLS/WED relies on clinical criteria, and the only instrumental tool, the suggested immobilization test, may lead to equivocal results. Recently, neurophysiological parameters related to F-wave duration have been proposed as a diagnostic aid. The aim of this study is to assess and compare the diagnostic values of these parameters in diagnosis of RLS/WED. Methods: Fifteen women affected by primary RLS/WED and 17 age-and sex-matched healthy subjects. A complete electroneurographic evaluation, including nerve conduction studies (NCS), cutaneous silent period (CSP), and F-wave parameters, namely amplitude, F-wave duration (FWD), and the ratio between FWD and duration of the corresponding compound muscle action potential (FWD/CMAPD). Results:No subject showed alterations of the NCS. However, FWD and FWD/CMAPD of both upper and lower limbs were significantly longer in patients than controls. Tibial FWD/CMAPD best discriminated RLS/WED patients from controls. A cutoff of 2.06 yielded a sensitivity of 69.2%, a specificity of 94.1%, a positive predictive power of 90%, and a negative predictive power of 80% (area under the curve = 0.817; 95% confidence interval = 0.674-0.959). The combination of ulnar or tibial FWD/CMAPD increases the sensitivity (85.7%) while slightly decreasing the specificity (87.5%, positive predictive value: 85.7%, negative predictive value: 87.5%). Conclusions: Lower limb FWD/CMAPD ratio may represent a supportive diagnostic tool, especially in cases of evening lower leg discomfort of unclear interpretation.

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“…Although several methodologies have been used to estimate human motoneuron excitability, few of them are applicable to detect age-related differences during strong maximal muscle contractions (McNeil et al 2013). Indeed, this is an important aspect since it also reflects the changes of the fast twitch muscle fibers, which are closely linked to balance adjustments and fall prevention (Hvid et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Strength training-induced responses in older adults: attenuation of descending neural drive with age

Unhjem

Lundestad

Fimland

et al. 2015

AGE

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Although reductions in resting H-reflex responses and maximal firing frequency suggest that reduced efferent drive may limit muscle strength in elderly, there are currently no reports of V-wave measurements in elderly, reflecting the magnitude of efferent output to the muscle during maximal contraction. Furthermore, it is uncertain whether potential age-related neural deficiencies can be restored by resistance training. We assessed evoked reflex recordings in the triceps surae muscles during rest and maximal voluntary contraction (MVC), rate of force development (RFD), and muscle mass in seven elderly (74±6 years) males before and after 8 weeks of heavy resistance training, contrasted by seven young (24±4 years) male controls. At baseline, m. soleus (SOL) V/M ratio (0.124±0.082 vs. 0. 465±0.197, p<0.05)

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Testing the excitability of human motoneurons

Cited by 183 publications

References 86 publications

Modulation of soleus corticospinal excitability during Achilles tendon vibration

Modulation of soleus corticospinal excitability during Achilles tendon vibration

F-Wave Duration as a Specific and Sensitive Tool for the Diagnosis of Restless Legs Syndrome/Willis-Ekbom Disease

Strength training-induced responses in older adults: attenuation of descending neural drive with age

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