Search results for "MAGNETIC STIMULATION"

Magnetic stimulation in the definition of eloquent cortical areas

2003

Publisher Summary This chapter discusses the physiological principles of transcranial magnetic stimulation (TMS) and focus on detailing the techniques used in TMS mapping of the motor cortex relating it to the use of TMS in the presurgical assessment of patients with epilepsy. Since the main measure of TMS is the motor potential evoked in muscles, fine delineation of the functional topography of cortex is limited mainly to the primary sensorimotor cortex. In addition, TMS might be helpful to identify language dominance. The characterization of eloquent cortical areas is important in epilepsy surgery for the planning of the resection. TMS is not routinely employed for this purpose and TMS ma…

Test-retest reliability of motor-evoked potentials at 20% and 60% of maximum isometric voluntary contraction in rectus femoris muscle

2023

Interleukin 10 restores lipopolysaccharide-induced alterations in synaptic plasticity probed by repetitive magnetic stimulation

2020

Systemic inflammation is associated with alterations in complex brain functions such as learning and memory. However, diagnostic approaches to functionally assess and quantify inflammation-associated alterations in synaptic plasticity are not well-established. In previous work, we demonstrated that bacterial lipopolysaccharide (LPS)-induced systemic inflammation alters the ability of hippocampal neurons to express synaptic plasticity, i.e., the long-term potentiation (LTP) of excitatory neurotransmission. Here, we tested whether synaptic plasticity induced by repetitive magnetic stimulation (rMS), a non-invasive brain stimulation technique used in clinical practice, is affected by LPS-induc…

Impaired glutamatergic neurotransmission in migraine with aura? Evidence by an input-output curves transcranial magnetic stimulation study.

2011

Objective: An imbalance between activity of inhibitory and facilitatory intracortical circuits could play a central role in migraine etiology. We used input-output curves to achieve further information about intracortical excitability of motor cortex in migraine with aura. METHODS: Input-output curves were measured in the right abductor pollicis brevis muscle at rest in 12 patients suffering from migraine with aura and 8 healthy subjects. Stimuli were delivered at intensity ranging from 100% to 160% of resting motor threshold with 10-second inter-stimulus intervals. Seven patients were studied before and during treatment with levetiracetam. RESULTS: Results showed a greater motor-evoked pot…

Possible Contribution of T-pattern Detection and Analysis to the Study of the Behavioral Correlates of Afferent Inhibition.

2020

A pivotal tenet in modern behavioral sciences is that the study of behavior, in its most intimate structure, necessarily deals with time and, for this reason, behavioral dynamics are not intuitively perceivable and/or detectable (Eibl-Eibesfeldt, 1970). In reality, the possibility to describe a given behavior in terms of its structural/temporal features makes available new and detailed information otherwise unavailable. The aim of the present paper is to discuss the possible application of T-pattern detection and analysis, i.e., a multivariate approach specifically developed to describe the temporal structure of behavior, to the study of an important and still scantly investigated issue, na…

Distilling the essence of TMS-evoked EEG potentials (TEPs): A call for securing mechanistic specificity and experimental rigor

2019

Alpha-Synchronized Stimulation of the Dorsolateral Prefrontal Cortex (DLPFC) in Major Depression: A Proof-of-Principle EEG-TMS Study

2018

High-frequency repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC) shows therapeutic potential in pharmaco-resistant patients with major depression. However, clinical efficacy is limited by high inter-individual variability and low response rates. One possible strategy to improve the effect size and consistency may be brain state dependent brain stimulation, i.e. coupling of TMS pulses to the endogenous brain states as reflected by the instantaneous oscillatory brain activity. Here we present findings from a proof-of-principle study of alpha-oscillation synchronized brain stimulation of the frontal cortex in patients with major depression (…

TMS-EEG signatures of glutamatergic neurotransmission in human cortex

2019

AbstractNeuronal activity in the brain is regulated by an excitation-inhibition balance. Glutamate is the main excitatory neurotransmitter. Transcranial magnetic stimulation (TMS) evoked electroencephalographic (EEG) potentials (TEPs) represent a novel way to quantify pharmacological effects on neuronal activity in the human cortex. Here we tested TEPs under the influence of a single oral dose of two anti-glutamatergic drugs, perampanel, an AMPA-receptor antagonist, and dextromethorphan, an NMDA-receptor antagonist, and nimodipine, an L-type voltage-gated calcium channel blocker in 16 healthy adults in a pseudorandomized, double-blinded, placebo-controlled, crossover design. Single-pulse TM…

The Neurophysiological Responses of Concussive Impacts: A Systematic Review and Meta-Analysis of Transcranial Magnetic Stimulation Studies

2020

Aim: This systematic review and meta-analysis investigated neurophysiological responses using transcranial magnetic stimulation (TMS) following a concussion or sub-concussion. Methods: A systematic searching of relevant databases for peer-reviewed literature quantifying motor evoked potentials from TMS between 1999 and 2019 was performed. A meta-analysis quantified pooled data for measures including motor threshold, motor latency, and motor evoked potential amplitude and for inhibitory measures such as cortical silent period duration, short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI) ratios. Results: Fifteen articles met the inclusion criteria…

A transcranial magnetic stimulation study evaluating methylprednisolone treatment in multiple sclerosis

2002

Objective To investigate the efficacy of two different high doses of intravenous methylprednisolone (IVMP) during Multiple Sclerosis (MS) relapses. Background Transcranial Magnetic Stimulation (TMS) is the most sensitive neurophysiological ascertainment to quantify motor disability, to follow the recovery from an MS relapse, and to detect the response to treatment. Design and method Twenty-four clinically definite relapsing - remitting MS patients presenting a relapse were randomly assigned to a treatment for 5 days with IVMP 1 or 2 g/day. The response to treatment of each patient was evaluated through Expanded Disability Status Scale (EDSS), Medical Research Council (MRC) score, and TMS by…