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Corticospinal excitability

Jakob Škarabot, Jamie Tallent, Stuart Goodall, Rade Durbaba, Glyn Howatson
NEW FINDINGS: What is the central question of this study? Relationship between motor unit recruitment and firing rate has been related to the size of the corticospinal output with variations in the nervous system gain during isometric contractions. However, corticospinal behaviour with incremental torque output might differ during anisometric contractions due to differences in neural control of anisometric contraction types. What is the main finding and its importance? Corticospinal excitability during lengthening contractions was smaller compared to shortening, but increased with incremental torque output similarly between contraction types...
October 4, 2018: Experimental Physiology
Carmen Kohl, Laure Spieser, Bettina Forster, Sven Bestmann, Kielan Yarrow
The neural dynamics underpinning binary perceptual decisions and their transformation into actions are well studied, but real-world decisions typically offer more than two response alternatives. How does decision-related evidence accumulation dynamically influence multiple action representations in humans? The heightened conservatism required in multiple compared with binary choice scenarios suggests a mechanism that compensates for increased uncertainty when multiple choices are present by suppressing baseline activity...
October 2, 2018: Journal of Cognitive Neuroscience
Natalie Schaworonkow, Jochen Triesch, Ulf Ziemann, Christoph Zrenner
BACKGROUND: Corticospinal excitability depends on the current brain state. The recent development of real-time EEG-triggered transcranial magnetic stimulation (EEG-TMS) allows studying this relationship in a causal fashion. Specifically, it has been shown that corticospinal excitability is higher during the scalp surface negative EEG peak compared to the positive peak of μ-oscillations in sensorimotor cortex, as indexed by larger motor evoked potentials (MEPs) for fixed stimulation intensity...
September 21, 2018: Brain Stimulation
Cassandra J Lowe, Peter A Hall
Despite the increasing use of continuous theta burst (cTBS) protocols targeting the prefrontal cortex in clinical and research settings, very little is known regarding the interindividual factors that influence the magnitude and duration of cTBS aftereffects. The few existing studies have predominantly focussed on motor and corticospinal excitability, and the applicability of such findings to prefrontal modulation remains unclear. The current investigation aggregated published data from our laboratory to (1) assess the reproducibility of the effects of cTBS targeting the left dorsolateral prefrontal cortex (dlPFC) on executive function task performance, and (2) determine which factors are associated with individual differences in cTBS responsivity...
September 26, 2018: Neuroscience Letters
Carmenrita Infortuna, Thomas F Milisits, Sherwin Shaju, Jignesh K Desai, Sapan P Patel, Asad M Sheikh, Eileen Chusid, Zhiyong Han, Fortunato Battaglia
Taurine (TAU) is one of the most abundant amino acids in the brain. It has many important physiological functions. The effects of TAU supplementation on brain function need to be further characterized in humans. The purpose of this study was to investigate whether a single dose of Taurine (TAU) intake would modulate corticospinal excitability and post-exercise facilitation (PEF) of the motor evoked potentials (MEP).
September 21, 2018: Behavioural Brain Research
Flavio O Pires, Carlos A S Dos Anjos, Roberto J M Covolan, Eduardo B Fontes, Timothy D Noakes, Alan St Clair Gibson, Fernando H Magalhães, Carlos Ugrinowitsch
Caffeine (CAF) is an ergogenic aid used to improve exercise performance. Independent studies have suggested that caffeine may have the ability to increase corticospinal excitability, thereby decreasing the motor cortex activation required to generate a similar motor output. However, CAF has also been suggested to induce a prefrontal cortex (PFC) deoxygenation. Others have suggested that placebo (PLA) may trigger comparable effects to CAF, as independent studies found PLA effects on motor performance, corticospinal excitability, and PFC oxygenation...
2018: Frontiers in Physiology
Robin Souron, Marie Oriol, Guillaume Y Millet, Thomas Lapole
While local vibration (LV) has been recently proposed as a potential modality for neuromuscular conditioning, no practical recommendations to optimize its effects have been published. Because changes in corticospinal excitability may reflect at which degree the neuromuscular function is modulated during LV exposure, this study investigated the effects of muscle length and vibration site on LV-induced on motor evoked potentials (MEPs) changes. Twenty-one subjects participated in a single session in which MEPs were evoked on the relaxed knee extensors (KE) during three conditions, i...
2018: Frontiers in Physiology
Callum G Brownstein, Paul Ansdell, Jakob Škarabot, Glyn Howatson, Stuart Goodall, Kevin Thomas
The study aimed to determine the optimal application of single- and paired-pulse transcranial magnetic stimulation (TMS) in the rectus femoris. Twenty-nine male adults participated in the study, which involved 5 separate experiments. Experiments 1 to 3 assessed the effect of conditioning stimulus (CS) intensity (60, 70, 80 and 90% active motor threshold, AMT), contraction strength (5, 10, 20 and 50% maximum voluntary contraction, MVC), and inter-stimulus interval (ISI, 2-5 ms for short-interval intracortical inhibition, SICI and 10-15 ms for intracortical facilitation, ICF) on SICI and ICF...
November 15, 2018: Journal of the Neurological Sciences
Kento Nakagawa, Kimitaka Nakazawa
Objective: Transcranial static magnetic field stimulation has recently been demonstrated to modulate cortical excitability. In the present study, we investigated the effect of transspinal static magnetic field stimulation (tsSMS) on excitability of the corticospinal tract. Methods: A compact magnet for tsSMS (0.45 Tesla) or a stainless steel cylinder for sham stimulation was positioned over the neck (C8 level) of 24 able-bodied subjects for 15 min. Using 120% of the resting motor threshold transcranial magnetic stimulation intensity, motor evoked potentials (MEPs) were measured from the first digital interosseous muscle before, during, and after the tsSMS or sham intervention...
2018: Clinical Neurophysiology Practice
Florian Vitry, Alain Martin, Gaëlle Deley, Maria Papaiordanidou
The aim of the study was to identify stimulation conditions permitting the occurrence of extra-torque (ET) and to examine their impact on spinal and corticospinal excitabilities. Twelve subjects received stimulation trains over the tibial nerve (20 sec duration, 1ms pulse duration) that were delivered at three stimulation frequencies (20, 50 and 100 Hz) and at 5 intensities (110, 120, 130, 140 and 150% of the motor threshold). Torque-Time Integral (TTI) of each stimulation train was calculated. Spinal (Hmax /Mmax ) and corticospinal (MEPmax /Mmax ) excitabilities were assessed at rest before and after each stimulation train by tibial nerve stimulation and by transcranial magnetic stimulation, respectively...
September 13, 2018: Journal of Applied Physiology
Benedikt Lauber, Albert Gollhofer, Wolfgang Taube
The tibialis anterior (TA) and the soleus (SOL) are both ankle joint muscles with functionally very different tasks. Thus, differences in motor cortical control between the TA and the SOL have been debated. This study compared the activity of the primary motor cortex during dynamic plantar- and dorsiflexions and compared this with measures obtained during rest. Single- and paired-pulse transcranial magnetic stimulations known as short-interval intracortical inhibition (SICI) were applied to the cortical representation of either the soleus or the tibialis muscle...
September 7, 2018: Journal of Experimental Biology
Michael Pellegrini, Maryam Zoghi, Shapour Jaberzadeh
High degrees of variability reported in Transcranial magnetic stimulation (TMS) assessment of corticospinal excitability (CSE) highlight the need to investigate its reliability as an assessment tool. This study investigated the effect of TMS test intensity on the amplitude, variability and test-retest reliability of motor evoked potentials (MEP). Twenty-five MEPs were recorded at 105%, 120%, 135%, 150% and 165% of resting motor threshold across three sessions in twelve participants. Repeated measures analysis of variance (RM-ANOVA), recruitment curve gradients and standardised z-value SDs were utilized to investigate the effect of TMS test intensity on MEP amplitude and variability...
September 4, 2018: Brain Research
Hai-Jiang Meng, Yan-Ling Pi, Ke Liu, Na Cao, Yan-Qiu Wang, Yin Wu, Jian Zhang
Background: Both motor imagery (MI) and motor execution (ME) can facilitate motor cortical excitability. Although cortical excitability is modulated by intracortical inhibitory and excitatory circuits in the human primary motor cortex, it is not clear which intracortical circuits determine the differences in corticospinal excitability between ME and MI. Methods: We recruited 10 young healthy subjects aged 18-28 years (mean age: 22.1 ± 3.14 years; five women and five men) for this study...
2018: PeerJ
Robert Guggenberger, Dominic Kraus, Georgios Naros, Maria Teresa Leão, Ulf Ziemann, Alireza Gharabaghi
BACKGROUND: Pairing cortical and peripheral input during motor imagery (MI)-related sensorimotor desynchronization (ERD) modulates corticospinal excitability at the cortical representation (hotspot) of the imagined movement. OBJECTIVE: To determine the effects of this associative stimulation protocol on the cortical motor map beyond the hotspot. METHODS: In healthy subjects, peripheral stimulation through passive hand opening by a robotic orthosis and single-pulse transcranial magnetic stimulation to the respective cortical motor representation were applied in a brain-machine interface environment...
August 22, 2018: Brain Stimulation
Moussa A Chalah, Ulrich Palm, Jean-Pascal Lefaucheur, Alain Créange, Samar S Ayache
BACKGROUND: Depression and anxiety stand among the most frequent and debilitating complaints in multiple sclerosis (MS) patients. Understanding their neurophysiological correlates might improve their management. To date, no single study has addressed this issue. METHOD: Patients completed the Hospital Anxiety and Depression Scale (HADS). Transcranial magnetic stimulation (TMS) was performed to obtain the following corticospinal excitability measures: resting motor threshold, short interval intracortical inhibition and facilitation, cortical silent period and interhemispheric inhibition...
August 30, 2018: Brain Research
Mitsuaki Takemi, Tsuyoshi Maeda, Yoshihisa Masakado, Hartwig Roman Siebner, Junichi Ushiba
Bridging between brain activity and machine control, brain-computer interface (BCI) can be employed to activate distributed neural circuits implicated in a specific aspect of motor control. Using a motor imagery-based BCI paradigm, we previously found a disinhibition within the primary motor cortex contralateral to the imagined movement, as evidenced by event-related desynchronization (ERD) of oscillatory cortical activity. Yet it is unclear whether this BCI approach does selectively facilitate corticomotor representations targeted by the imagery...
August 30, 2018: NeuroImage
Chun-Wei Wu, Wen-Tai Chiu, Tsung-Hsun Hsieh, Cho-Han Hsieh, Jia-Jin Jason Chen
Intermittent theta burst stimulation (iTBS) and continuous theta burst stimulation (cTBS) are protocols used in repetitive transcranial magnetic stimulation (rTMS) or cortical electrical stimulation (CES) to facilitate or suppress corticospinal excitability. However, rTMS and CES excite all types of neuron in the target cortex probed by the coil or electrode, making it difficult to differentiate the effect of TBS on specific neural circuits involved in motor plasticity. In this study, TBS protocols were converted into an optogenetic model to achieve focalized and cell-type-specific cortical modulation...
2018: PloS One
Thomas J O'Leary, Johnny Collett, Martyn G Morris
The development of fatigue during single-joint isolated muscle contractions is accompanied by an increase in long-interval intracortical inhibition (LICI). However, the effect of whole-body locomotor endurance exercise on LICI is unknown. Eighteen healthy men completed three exercise trials on a cycle ergometer. The first trial was completed to determine the lactate threshold (LT) and maximal oxygen uptake ([Formula: see text]). The remaining two trials (familiarisation and experimental) involved cycling to volitional exhaustion at an intensity equivalent to halfway between the LT and [Formula: see text] (50%Δ)...
August 25, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Natsumi Ishikawa, Ryunosuke Miyao, Shota Tsuiki, Ryoki Sasaki, Shota Miyaguchi, Hideaki Onishi
Post-exercise cortical depression (PED) is induced by non-fatiguing finger movement. Because the type of exercise that causes PED remains unclear, we conducted two experiments to clarify which exercise factors induce PED. Fifteen healthy participants performed repetitive abduction movements of the right index finger at 2.0 Hz (simple rhythmic task) and 0.2 Hz (adjustment task) for 6 min each in experiment 1. Twelve healthy participants performed repetitive and isometric abduction contractions of the right index finger at 1...
November 2018: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Sonia Betti, Giovanni Zani, Umberto Granziol, Silvia Guerra, Umberto Castiello, Luisa Sartori
Direct gaze is a powerful social cue able to capture the onlooker's attention. Beside gaze, head and limb movements as well can provide relevant sources of information for social interaction. This study investigated the joint role of direct gaze and hand gestures on onlookers corticospinal excitability (CE). In two experiments we manipulated the temporal and spatial aspects of observed gaze and hand behavior to assess their role in affecting motor preparation. To do this, transcranial magnetic stimulation (TMS) on the primary motor cortex (M1) coupled with electromyography (EMG) recording was used in two experiments...
2018: Frontiers in Psychology
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