Search results for "Transcranial"
showing 10 items of 413 documents
Extracranial Venous Drainage Pattern in Multiple Sclerosis and Healthy Controls: Application of the 2011 Diagnostic Criteria for Chronic Cerebrospina…
2015
The etiology of multiple sclerosis (MS) is still largely unknown and it has been proposed that an impaired venous drainage from the central nervous system, defined as chronic cerebrospinal venous insufficiency (CCSVI), may play a role in this. We investigated the prevalence of extracranial venous drainage pattern alterations in a cohort of MS patients based on the 2011 revised diagnostic criteria for CCSVI. Thirty-nine MS patients and 18 healthy subjects underwent blinded extra-cranial venous echo-color Doppler sonography to reveal the presence of CCSVI. There was no statistically significant difference between MS patients and healthy controls regarding CCSVI prevalence (p value = 0.53). Th…
Modulation of pain perception by transcranial magnetic stimulation of left prefrontal cortex.
2010
Evidence by functional imaging studies suggests the role of left dorsolateral prefrontal cortex (DLPFC) in the inhibitory control of nociceptive transmission system. Repetitive transcranial magnetic stimulation (rTMS) is able to modulate pain response to capsaicin. In the present study, we evaluated the effect of DLPFC activation (through rTMS) on nociceptive control in a model of capsaicin-induced pain. The study was performed on healthy subjects that underwent capsaicin application on right or left hand. Subjects judged the pain induced by capsaicin through a 0–100 VAS scale before and after 5 Hz rTMS over left and right DLPFC at 10 or 20 min after capsaicin application in two separate gr…
The ipsilateral corticospinal responses to cross-education are dependent upon the motor-training intervention
2018
This study aimed to identify the ipsilateral corticospinal responses of the contralateral limb following different types of unilateral motor-training. Three groups performing unilateral slow-paced strength training (SPST), non-paced strength training (NPST) or visuomotor skill training (VT) were compared to a control group. It was hypothesised that 4 weeks of unilateral SPST and VT, but not NPST, would increase ipsilateral corticospinal excitability (CSE) and reduce short-interval cortical inhibition (SICI), resulting in greater performance gains of the untrained limb. Tracking error of the untrained limb reduced by 29 and 41% following 2 and 4 weeks of VT. Strength of the untrained limb in…
Does habituation depend on cortical inhibition? Results of a rTMS study in healthy subjects
2010
Habituation, i.e. the decremental response to repeated sensorial stimulation, is studied in humans through evoked potential stimulation. Mechanisms underlying habituation are not yet cleared, even if inhibitory circuits are supposed to play an important role. Light deprivation (LD) increases visual cortical excitability likely through down-regulation of GABA circuits. We previously found that high-frequency repetitive transcranial magnetic stimulation (hf-rTMS) can revert these facilitatory effects likely restoring the activity of inhibitory circuits. Here, we studied the effects of LD and rTMS on habituation of visual evoked potentials (VEPs). The hypothesis was that if the inhibitory circ…
Image-guided transcranial Doppler sonography for monitoring of vasospasm after subarachnoid hemorrhage.
2016
Transcranial Doppler ultrasound (TCD) is a standard method for bedside vasospasm monitoring after subarachnoid hemorrhage (SAH). Image guidance has previously been shown to reduce intra- and interobserver variability of this method. The aim of the present study was to compare image-guided and conventional TCD in vasospasm monitoring after SAH.418 TCD exams of 24 consecutive SAH patients registered in a database were evaluated. Of these, 130 image-guided exams were identified which had been performed on the same day as conventional Doppler exams. These matched pairs were taken for statistical analysis. Data were tested statistically using the sign test applied at patient level to aggregated …
Fast increase of motor cortical inhibition following postural changes in healthy subjects.
2012
BACKGROUND AND AIMS: Postural reactions are associated with changes in the excitability of the motor system. In the present study we investigated the presence of neurophysiological changes of motor cortical areas targeting muscles of the inferior limbs following treatment with a physiotherapy technique aimed to treat postural dysfunctions by stretching postural muscles, global postural reeducation (GPR). METHODS: Twenty healthy subjects were evaluated with paired-transcranial magnetic stimulation (TMS) of the motor cortex and recording of motor evoked potentials (MEPs) from peripheral muscles of the inferior limb before and after two GPR manoeuvres applied in different experiments (1 and 2)…
The role of posterior parietal cortices on prismatic adaptation effects on the representation of time intervals
2013
Previous studies provided evidence of an ascending left-to-right spatial representation of time durations by using a technique affecting high levels of spatial cognition, i.e. prismatic adaptation (PA). Indeed, PA that induced a leftward aftereffect distorted time representation toward an underestimation, while PA that induced a rightward aftereffect distorted time representation toward an overestimation. The present study advances previous findings on the effects of PA on time by investigating the neural basis subtending these effects. We focused on the posterior parietal cortex (PPC) since it is involved in the PA procedure and also in the formulation of the spatial representation of time…
Influence of Delay Period Duration on Inhibitory Processes for Response Preparation.
2015
In this study, we examined the dynamics of inhibitory preparatory processes, using a delayed response task in which a cue signaled a left or right index finger (Experiment 1) or hand (Experiment 2) movement in advance of an imperative signal. In Experiment 1, we varied the duration of the delay period (200, 500, and 900 ms). When transcranial magnetic stimulation (TMS) was applied 100 ms before the imperative, motor evoked potentials (MEPs) elicited in the first dorsal interosseous were strongly inhibited. For delays of 500 ms or longer, this inhibition was greater when the targeted muscle was selected compared with when it was not selected. In contrast, the magnitude of inhibition just aft…
Changes in corticospinal excitability during an acute bout of resistance exercise in the elbow flexors
2014
Purpose Hypertrophic resistance exercise (HRE) induces central and peripheral fatigue. However, more detailed information about changes in corticospinal excitability remains to be elucidated. Methods Eleven volunteers participated in the upper arm HRE which included one repetition maximum (1 RM) control contractions and three sets of 13 RM (SET1–3). Transcranial magnetic stimulation (TMS) was applied during maximal isometric voluntary contraction (MVC) at the end of each set and during control contractions to study changes in corticospinal excitability. Electrical stimulation was used in order to measure peripheral changes. Results MVC decreased after each set when compared to control contr…
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…