Search results for "Transcranial"

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 …

Effects of low-gamma tACS on primary motor cortex in implicit motor learning

2019

Abstract In the primary motor cortex (M1), rhythmic activity in the gamma frequency band has been found during movement planning, onset and execution. Although the role of high-gamma oscillatory activity in M1 is well established, the contribution of low-gamma activity is still unexplored. In this study, transcranial alternating current stimulation (tACS) was used with the aim to specifically modulate low-gamma frequency band in M1, during an implicit motor learning task. A 40 Hz-tACS was applied over the left M1 while participants performed a serial reaction time task (SRTT) using their right hand. The task required the repetitive execution of sequential movements in response to sequences …

Motor cortical plasticity induced by motor learning through mental practice

2015

Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP)-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1) excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after …

Transcranial magnetic resonance imaging-guided focused ultrasound treatment at 1.5 T: A retrospective study on treatment- and patient-related paramet…

2020

Anodal transcranial direct current stimulation and intermittent theta-burst stimulation improve deglutition and swallowing reproducibility in elderly…

2019

Background: Dysphagia in the elderly, known as presbydysphagia, has become a relevant public health problem in several countries. Swallowing disorders may be a consequence of different neurological disorders (secondary presbydysphagia) or the expression of the aging process itself (primary presbydysphagia). We aimed to test the therapeutic potential of two different non-invasive brain stimulation (NIBS) techniques in subjects with primary or secondary presbydysphagia. Methods: A blinded randomized controlled trial with crossover design was carried out in 42 patients, randomly assigned to anodal transcranial direct current stimulation (tDCS) or intermittent theta-burst stimulation (TBS) grou…

The role of Posterior Parietal Cortex in spatial representation of time: a TMS study.

2011

1. Introduction. The existence of a spatial representation of time, where temporal intervals are represented on a mental temporal line (MTL), oriented in ascending order from left to right, was demonstrated manipulating spatial attention by means of Prismatic Adaptation (PA). In young healthy subjects, prisms adaptation inducing a rightward shift of spatialattention produced an overestimation of time intervals, whereas prisms adaptation inducing a leftward shift of spatialattention produced an underestimation of time intervals [4]. The aimof the present study was to investigate the neural basis mediating the effects of PA on spatial time representation. PosteriorParietalCortex (PPC) is the …

P 96. Prismatic lenses as a novel tool to directionally manipulate motor cortex excitability: Evidence from paired-pulse TMS

2013

Introduction Prismatic adaptation (PA) is a visuo-motor procedure requiring participants to adapt to prismatic lenses shifting the visual scene horizontally. Such an adaptation produces a phenomenon called “after-effect”, opposite to the side of lenses deviation. The after-effect has been frequently associated with a shift of spatial attention in the same direction and with a restoration of hemispatial neglect symptoms. PA has captured the interest of neuroscientists in the last decades, since it affects high-order spatial cognition even thought consisting of low-level visuo-motor processes. Objectives Despite a huge literature on this procedure, the basic neural processes related to PA and…

High-definition transcranial direct current stimulation to both primary motor cortices improves unimanual and bimanual dexterity.

2017

While most research on brain stimulation with transcranial direct current stimulation (tDCS) targets unimanual motor tasks, little is known about its effects on bimanual motor performance. This study aims to investigate the effects of tDCS on unimanual as well as bimanual motor dexterity. We examined the effects of bihemispheric anodal high-definition tDCS (HD-atDCS) on both primary motor cortices (M1) applied concurrent with unimanual and bimanual motor training. We then measured the effects with the Purdue Pegboard Test (PPT) and compared them to a sham stimulation. Between a pretest and posttest, 31 healthy, right-handed participants practiced the PPT on three consecutive days and receiv…

Brain oscillations: discovering their role in memory using Transcranial Alternating Current Stimulation

Excitability regulation in the dorsomedial prefrontal cortex during sustained instructed fear responses: a TMS-EEG study

2018

AbstractThreat detection is essential for protecting individuals from adverse situations, in which a network of amygdala, limbic regions and dorsomedial prefrontal cortex (dmPFC) regions are involved in fear processing. Excitability regulation in the dmPFC might be crucial for fear processing, while abnormal patterns could lead to mental illness. Notwithstanding, non-invasive paradigms to measure excitability regulation during fear processing in humans are missing. To address this challenge we adapted an approach for excitability characterization, combining electroencephalography (EEG) and transcranial magnetic stimulation (TMS) over the dmPFC during an instructed fear paradigm, to dynamica…