Search results for "excitability"
showing 10 items of 82 documents
Determining the Corticospinal Responses to Single Bouts of Skill and Strength Training
2019
Mason, J, Frazer, AK, Jaberzadeh, S, Ahtiainen, JP, Avela, J, Rantalainen, T, Leung, M, and Kidgell, DJ. Determining the corticospinal responses to single bouts of skill and strength training. J Strength Cond Res 33(9): 2299-2307, 2019-Neuroplastic changes in the primary motor cortex accompany performance improvements following motor practice. Recent evidence suggests that the corticospinal responses to strength and skill training are similar, following both a single session and repeated bouts of training, promoting discussion that strength training is a form of motor learning. However, these findings are limited by the lack of a light-load strength training group. Therefore, the aim of the…
Cutaneous Recording and Stimulation of Muscles Using Organic Electronic Textiles
2016
International audience; Electronic textiles are an emerging field providing novel and non-intrusive solutions for healthcare. Conducting polymer-coated textiles enable a new generation of fully organic surface electrodes for electrophysiological evaluations. Textile electrodes are able to assess high quality muscular monitoring and to perform transcutaneous electrical stimulation.
Hypo-excitability of cortical areas in patients affected by Friedreich ataxia: A TMS study
2005
The aim of the study was to explore excitability of a motor and a non-motor (visual) area in patients affected by Friedreich ataxia and to correlate neurophysiological data with clinical parameters. Seven patients (3M/4F) and ten healthy controls (5M/5F) participated in the study. The hot-spot for activation of right abductor pollicis brevis was checked by means of a figure-of-eight coil and the motor threshold (MT) on this point was recorded. The phosphene threshold (PT) was measured by means of a focal coil over the occipital cortex as the lower intensity of magnetic stimulation able to induce the perception of phosphenes. The patients showed a significantly higher mean PT (p<.03) and MT …
Neurophysiological insights on flexibility improvements through motor imagery
2017
International audience; The efficacy of motor imagery (MI) practice to facilitate muscle stretching remains controversial and the underlying neurophysiological mechanisms unexplored. We evaluated the effects of MI practice during a sit-and reach task. Healthy participants were randomly assigned to a MI practice (n = 15) or Control (n = 15) group and completed 2 blocks of 5 sit-and-reach trials. During the first block (B1), participants performed 5 maximal stretching trials of 10s. During the second block (B2), trials were divided into two consecutive parts: i) reproducing the maximum performance of B1 (10s, B2 part 1), and ii) attempting to outperform the maximum performance of B1 (10s, B2 …
Inter- and intra-individual variability of paired-pulse curves with transcranial magnetic stimulation (TMS).
2002
Objectives: Previous studies have evaluated the variability of motor thresholds (MTs) and amplitude of motor-evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) within and across individuals. Here we evaluate the reproducibility and inter-hemispheric variability of measures of cortical excitability using the 'conventional' paired-pulse (PP) TMS technique. Methods: We studied PP curves of the left and right hemisphere in 10 healthy subjects on two separate days 2 weeks apart. The inter-stimulus intervals studied were 1, 3, 6, 8, 10 and 12 ms with the conditioning stimulus being 80% of the resting MT, and a single test stimulus producing MEPs of approximately 0.8 mV peak-to-pe…
Multisensorial Perception in Chronic Migraine and the Role of Medication Overuse.
2020
Multisensory processing can be assessed by measuring susceptibility to crossmodal illusions such as the Sound-Induced Flash Illusion (SIFI). When a single flash is accompanied by 2 or more beeps, it is perceived as multiple flashes (fission illusion); conversely, a fusion illusion is experienced when more flashes are matched with a single beep, leading to the perception of a single flash. Such illusory perceptions are associated to crossmodal changes in visual cortical excitability. Indeed, increasing occipital cortical excitability, by means of transcranial electrical currents, disrupts the SIFI (ie, fission illusion). Similarly, a reduced fission illusion was shown in patients with episod…
High-Frequency Transcranial Magnetic Stimulation on Motor Cortex of Patients Affected by Migraine With Aura: A Way to Restore Normal Cortical Excitab…
2009
We showed reduced motor intracortical inhibition (ICI) and paradoxical increase of intracortical facilitation (ICF) to 1 Hz repetitive transcranial magnetic stimulation (rTMS) in patients affected by migraine with aura (MA). In conditions of enhanced excitability due to a reduced inhibition, high-frequency rTMS was found to potentiate intracortical inhibition. Here we explored the conditioning effects of high-frequency priming stimulation of motor cortex with the aim of normalizing excitability reverting paradoxical facilitation by 1 Hz rTMS in MA. Nine patients with MA and nine healthy controls underwent a paired-pulse TMS paradigm to evaluate motor intracortical excitability (ICI and ICF…
Transcranial magnetic stimulation reveals cortical hyperexcitability in episodic cluster headache
2014
Abstract Evidence shows involvement of the cerebral cortex in the pathophysiology of cluster headache (CH). Here we investigated cortical excitability in episodic CH patients by using transcranial magnetic stimulation. In 25 patients with episodic CH and 13 healthy subjects we evaluated the motor cortical response to single-pulse (ie, motor threshold, input-output curves, cortical silent period) and paired-pulse (ie, intracortical facilitation, short intracortical inhibition) transcranial magnetic stimulation in both hemispheres. Thirteen patients were evaluated outside bout and the remaining 12 patients inside bout. Our results showed increased slope of the input-output curves after stimul…
Tracking the corticospinal responses to strength training
2020
Purpose\ud The motor cortex (M1) appears to be a primary site of adaptation following both a single session, and repeated strength-training sessions across multiple weeks. Given that a single session of strength-training is sufficient to induce modification at the level of the M1 and corticospinal tract, this study sought to determine how these acute changes in M1 and corticospinal tract might accumulate across the course of a 2-week heavy-load strength-training program.\ud \ud Methods\ud Transcranial magnetic stimulation (TMS) was used to infer corticospinal excitability (CSE), intracortical facilitation (ICF), short and long-interval intracortical inhibition (SICI and LICI) and silent per…
Modulation of visual cortex excitability in migraine with aura: effects of valproate therapy.
2009
We explored the effects of valproate treatment on visual cortex excitability changes in migraine with aura patients. Abnormal cortical excitability has been suggested to play an important role in the etiopathogenesis of migraine; in particular, it has been suggested a failure of inhibitory circuits in migraine with aura. Valproate acts as a central GABA agonist and it is reasonable suppose that VPA could modify cortical excitability state. Phosphene threshold (PT) was assessed at baseline and after 1 Hz rTMS before and after one month therapy. We found that low-frequency rTMS in drug-free migraineurs decreased PT, while the treatment with the GABA agonist valproate is able to revert the eff…