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Simulation of transcranial magnetic stimulation in head model with morphologically-realistic cortical neurons
Transcranial magnetic stimulation (TMS) enables non-invasive modulation of brain activity with both clinical and research applications, but fundamental questions remain about the neural types and elements TMS activates and how stimulation parameters affect the neural response.Conditions for numerically accurate TMS electric field simulation
Computational simulations of the E-field induced by transcranial magnetic stimulation (TMS) are increasingly used to understand its mechanisms and to inform its administration. However, characterization of the accuracy of the simulation methods and the factors that affect it is lacking.Cerebellar rTMS for motor control in progressive supranuclear palsy
Stimulatory cerebellar TMS is a promising tool to improve motor control in neurodegenerative disorders. Objective/hypothesis: Our goal was to use 10Hz cerebellar rTMS to augment cerebellar-brain inhibition (CBI) for improved postural stability and speech in patients with progressive supranuclear palsy (PSP).Safety, tolerability and effectiveness of a novel 20 Hz rTMS protocol targeting dorsomedial prefrontal cortex in major depression: An open-label case series
Repetitive transcranial magnetic stimulation (rTMS) of the dorsomedial prefrontal cortex (DMPFC) in treatment-resistant depression (TRD) has been recently studied as an alternative to conventional dorsolateral prefrontal cortex (DLPFC) rTMS [1,2]. Across both targets, intermittent theta-burst stimulation (iTBS) reduces treatment duration while achieving comparable outcomes to conventional 10 Hz stimulation [1,3]. However, iTBS can require more costly devices than conventional high-frequency rTMS, and the consistency of excitatory effect varies across individuals [4].Real-time estimation of electric fields induced by transcranial magnetic stimulation with deep neural networks
Transcranial magnetic stimulation (TMS) plays an important role in treatment of mental and neurological illnesses, and neurosurgery. However, it is difficult to target specific brain regions accurately because the complex anatomy of the brain substantially affects the shape and strength of the electric fields induced by the TMS coil. A volume conductor model can be used for determining the accurate electric fields; however, the construction of subject-specific anatomical head structures is time-consuming.Prestimulus cortical EEG oscillations can predict the excitability of the primary motor cortex
The motor evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation (TMS) vary considerably at rest, but the mechanism underlying this amplitude variation is largely unknown. We hypothesized that prestimulus EEG oscillations modulate the subsequent MEPs in a state-dependent manner.Cortico-spinal tDCS in ALS: A randomized, double-blind, sham-controlled trial
Amyotrophic lateral sclerosis (ALS) is a progressive disease which affects both upper and lower motor neurons, with a fatal prognosis, for which no curative treatment is currently available. Glutamate-driven excitotoxicity is supposed to be involved in its pathophysiology, and drugs such as riluzole or edaravone have shown to reduce disease progression in ALS to a limited extent.Stimulation over the cerebellum with a regular figure-of-eight coil induces reduced motor cortex inhibition in patients with progressive supranuclear palsy
To determine whether motor cortex inhibition by stimulation over the cerebellum with a figure-of eight coil (MISC8) may be reduced in patients with Progressive Supranuclear Palsy (PSP).A fast and general method to empirically estimate the complexity of brain responses to transcranial and intracranial stimulations
The Perturbational Complexity Index (PCI) was recently introduced to assess the capacity of thalamocortical circuits to engage in complex patterns of causal interactions. While showing high accuracy in detecting consciousness in brain-injured patients, PCI depends on elaborate experimental setups and offline processing, and has restricted applicability to other types of brain signals beyond transcranial magnetic stimulation and high-density EEG (TMS/hd-EEG) recordings.No trace of phase: Corticomotor excitability is not tuned by phase of pericentral mu-rhythm
The motor potentials evoked by transcranial magnetic stimulation (TMS) over the motor hand area (M1-HAND) show substantial inter-trial variability. Pericentral mu-rhythm oscillations, might contribute to inter-trial variability. Recent studies targeting mu-activity based on real-time electroencephalography (EEG) reported an influence of mu-power and mu-phase on the amplitude of motor evoked potentials (MEPs) in a preselected group with strong pericentral mu-activity. Other studies that determined mu-power or mu-phase based on post-hoc trial sorting according in non-preselected individuals were largely negative.Effects of cerebellar transcranial direct current stimulation on cerebellar-brain inhibition in humans: A systematic evaluation
Cerebellar transcranial direct current stimulation (ctDCS) is increasingly used to modulate cerebellar excitability and plasticity in healthy subjects and various patient populations. ctDCS parameters are poorly standardized, and its physiology remains little understood. Our aim was to compare the physiological effects of three different non-target electrode positions (buccinator muscle, supraorbital region, deltoid muscle).High intensity aerobic exercise does not prime the brain for anodal transcranial direct current stimulation
The benefits of both regular and acute exercise on cognitive function are well-established. One candidate mechanism is the increase in brain derived neurotropic factor (BDNF), which is involved in exercise-induced neuroplasticity [1]. An increase in serum BDNF after a single exercise session may create favourable conditions for adaptive plasticity [2], and has also been shown to influence anodal transcranial direct current stimulation (a-tDCS) in mice [3]. We investigated the acute effects of a single bout of high-intensity interval training (HIIT) performed prior to dorsolateral pre-frontal cortex (DLPFC) a-tDCS on cognitive performance, serum BDNF, and the cerebral haemodynamic response in healthy adults.Somatosensory and transcranial direct current stimulation effects on manual dexterity and motor cortex function: A metaplasticity study
Non-invasive neuromodulation may provide treatment strategies for neurological deficits affecting movement, such as stroke. For example, weak electrical stimulation applied to the hand by wearing a “mesh glove” (MGS) can transiently increase primary motor cortex (M1) excitability. Conversely, transcranial direct current stimulation with the cathode over M1 (c-tDCS) can decrease corticomotor excitability. Objective/Hypothesis: We applied M1 c-tDCS as a priming adjuvant to MGS and hypothesised metaplastic effects would be apparent in improved motor performance and modulation of M1 inhibitory and facilitatory circuits.Direction of TDCS current flow in human sensorimotor cortex influences behavioural learning
Recent studies have shown that neurophysiological outcomes of transcranial direct current stimulation (TDCS) are influenced by current flow in brain regions between the electrodes, and in particular the orientation of current flow relative to the cortical surface.Publication trends in transcranial magnetic stimulation: a 30-year panorama
Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulatory technique that has broad diagnostic and therapeutic potential across a range of neurological and psychiatric diseases.TMS motor mapping: Comparing the absolute reliability of digital reconstruction methods to the golden standard
Changes in transcranial magnetic stimulation motor map parameters can be used to quantify plasticity in the human motor cortex. The golden standard uses a counting analysis of motor evoked potentials (MEPs) acquired with a predefined grid. Recently, digital reconstruction methods have been proposed, allowing MEPs to be acquired with a faster pseudorandom procedure. However, the reliability of these reconstruction methods has never been compared to the golden standard.Motor training modulates intracortical inhibitory dynamics in motor cortex during movement preparation
The primary motor cortex (M1) has a vital role to play in the learning of novel motor skills. However, the physiological changes underpinning this learning, particularly in terms of dynamic changes during movement preparation, are incompletely understood. In particular, a substantial decrease in resting gamma-amino butyric acid (GABA) activity, i.e. a release of resting inhibition, is seen within M1 as a subject prepares to move. Although there is evidence that a decrease in resting inhibition occurs within M1 during motor learning it is not known whether the pre-movement “release” of GABAergic inhibition is modulated during skill acquisition.Excitability of the supplementary motor area in Parkinson's disease depends on subcortical damage
Cortical dysfunctioning significantly contributes to the pathogenesis of motor symptoms in Parkinson's disease (PD).LTP-like cortical plasticity is associated with verbal memory impairment in Alzheimer's disease patients
Alzheimer's disease (AD) is characterized by a primary impairment of long-term declarative memory caused by deposition of misfolded protein aggregates. Experimental studies showed that AD neuropathological alterations impair synaptic plasticity and memory performance. Transcranial Magnetic Stimulation protocols have been recently introduced to investigate altered mechanisms of cortical plasticity in AD patients.Limits and reproducibility of resting-state functional MRI definition of DLPFC targets for neuromodulation
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation technique with therapeutic applications for the treatment of major depressive disorder (MDD). The standard protocol uses high frequency stimulation over the left dorsolateral prefrontal cortex (DLPFC) identified in a heuristic manner leading to moderate clinical efficacy. A proposed strategy to increase the anatomical precision in targeting, based on resting-state functional MRI (rsfMRI), identifies the subregion within the DLPFC having the strongest anticorrelated functional connectivity with the subgenual cortex (SGC) for each individual subject.Randomized controlled trial of transcranial magnetic stimulation in pregnant women with major depressive disorder
Major depressive disorder (MDD) affects 10% of pregnancies. Because transcranial magnetic stimulation (TMS) is a nonmedication option, psychiatric patients who do not tolerate or prefer to avoid antidepressants are good candidates for TMS.Involvement of different neuronal components in the induction of cortical plasticity with associative stimulation
Paired associative stimulation (PAS), with stimulus interval of 21.5 or 25 ms, using transcranial magnetic stimulation in the posterior-anterior (PA) current direction, produces a long-term-potentiation-like effect. Stimulation with PA directed current generates both early and late indirect (I)-waves while that in anterior-posterior (AP) current predominantly elicits late I-waves. Short interval intracortical inhibition (SICI) inhibits late I-waves but not early I-waves.Modulation of cortical responses by transcranial direct current stimulation of dorsolateral prefrontal cortex: A resting-state EEG and TMS-EEG study
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Atlas of optimal coil orientation and position for TMS: A computational study
Transcranial magnetic stimulation (TMS) activates target brain structures in a non-invasive manner. The optimal orientation of the TMS coil for the motor cortex is well known and can be estimated using motor evoked potentials. However, there are no easily measurable responses for activation of other cortical areas and the optimal orientation for these areas is currently unknown.Neuropeptide Y as a possible homeostatic element for changes in cortical excitability induced by repetitive transcranial magnetic stimulation
Repetitive transcranial magnetic stimulation (rTMS) is able to modify cortical excitability. Rat rTMS studies revealed a modulation of inhibitory systems, in particular that of the parvalbumin-expressing (PV+) interneurons, when using intermittent theta-burst stimulation (iTBS).
