Modulation Of Cortical Excitability Research Articles

An investigation of the acute effects of aerobic exercise on executive function and cortical excitability in adolescents with attention deficit hyperactivity disorder (ADHD).

Previous studies have shown that aerobic exercise has beneficial effects on executive function in adolescents with attention-deficit hyperactivity disorder (ADHD). The underlying mechanisms could be partially due to aerobic exercise-induced cortical excitability modulation. The aim of this study was to explore the effects of acute aerobic exercise on executive functions and cortical excitability and the association between these phenomena in adolescents with ADHD. The study was conducted using a complete crossover design. Executive functions (inhibitory control, working memory, and planning) and cortical excitability were assessed in twenty-four drug-naïve adolescents with ADHD before and after acute aerobic exercise or a control intervention. Inhibitory control, working memory, and planning improved after acute aerobic exercise in adolescents with ADHD. Moreover, cortical excitability monitored by transcranial magnetic stimulation (TMS) decreased after intervention in this population. Additionally, improvements in inhibitory control and working memory performance were associated with enhanced cortical inhibition. The findings provide indirect preliminary evidence for the assumption that changes in cortical excitability induced by aerobic exercise partially contribute to improvements in executive function in adolescents with ADHD.

Always expect the unexpected: eye position modulates visual cortex excitability in a stimulus-free environment.

Stimuli that potentially require a rapid defensive or avoidance action can appear from the periphery at any time in natural environments. de Wit et al. (Cortex 127: 120-130, 2020) recently reported novel evidence suggestive of a fundamental neural mechanism that allows organisms to effectively deal with such situations. In the absence of any task, motor cortex excitability was found to be greater whenever gaze was directed away from either hand. If modulation of cortical excitability as a function of gaze location is a fundamental principle of brain organization, then one would expect its operation to be present outside of motor cortex, including brain regions involved in perception. To test this hypothesis, we applied single-pulse transcranial magnetic stimulation (TMS) to the right lateral occipital lobe while participants directed their eyes to the left, straight-ahead, or to the right, and reported the presence or absence of a phosphene. No external stimuli were presented. Cortical excitability as reflected by the proportion of trials on which phosphenes were elicited from stimulation of the right visual cortex was greater with eyes deviated to the right as compared with the left. In conjunction with our previous findings of change in motor cortex excitability when gaze and effector are not aligned, this eye position-driven change in visual cortex excitability presumably serves to facilitate the detection of stimuli and subsequent readiness to act in nonfoveated regions of space. The existence of this brain-wide mechanism has clear adaptive value given the unpredictable nature of natural environments in which human beings are situated and have evolved.NEW & NOTEWORTHY For many complex tasks, humans focus attention on the site relevant to the task at hand. Humans evolved and live in dangerous environments, however, in which threats arise from outside the attended site; this fact necessitates a process by which the periphery is monitored. Using single-pulse transcranial magnetic stimulation (TMS), we demonstrated for the first time that eye position modulates visual cortex excitability. We argue that this underlies at least in part what we term "surveillance attention."

Transcranial direct current stimulation: effects, clinical applications, and future perspectives in neurology and physical performance

Transcranial direct current stimulation (tDCS) is a noninvasive technique that allows modulation of cortical excitability and can produce changes in neuronal plasticity. The application of tDCS has recently been associated with respiratory muscles and several neurological disorders. Thus, this study is constructed in the format of an article, with the objective of discussing the effects, clinical applications and future perspectives related to Transcracenian Direct Current Stimulation in the respiratory muscles, as well as discussing the applications of tDCS in other areas, such as neurological and psychological aspects. As a research methodology, a literature review will be used in this study. This study discusses the clinical applications of tDCS in several diseases, such as Alzheimer's, Parkinson's disease, depression, drug and food compulsion, as well as its application in the process of physical and respiratory performance. Recent studies suggest that a new field of applicability of tDCS may be related to a probable ergogenic effect induced by it, especially on the production of muscle and respiratory strength, aerobic performance and perception of exertion.

Efficacy of transcranial magnetic stimulation in the treatment of alcohol dependence - a review article

Introduction: Alcohol addiction is a common health problem with many negative consequences. Due to the unsatisfactory results of existing treatment, research is being undertaken into new forms of therapy. One such method is transcranial magnetic stimulation. This technique involves applying a magnetic field to the central nervous system. Successive magnetic pulses are delivered at a specific frequency causing neurons depolarization. Such repetitive exposure allows for long-term modulation of cortical excitability, and thus can lead to specific clinical effects. This paper discusses scientific reports about the treatment of alcohol dependence using transcranial magnetic stimulation (both papers on conventional repetitive transcranial magnetic stimulation, theta burst stimulation and deep transcranial magnetic stimulation are included). Material and methods: Based on the search of the PubMed and Science Direct bibliographic databases, 12 studies published in the years 2010-2022 were selected. The results were tabulated to clearly compare differences in the parameters of stimulation, its location, as well as the effectiveness of the intervention used. Results: The results of selected studies were compared. Differences in methodology were pointed out and the problem of high dropout rate in addiction research was discussed. Conclusions: Currently, there is insufficient evidence to recommend the use of transcranial magnetic stimulation in the treatment of alcohol dependence. The results of the studies conducted to date are mixed. This is due, among other things, to the choice of different protocols, techniques and stimulation sites. For a reliable assessment of the effectiveness of this form of therapy, more andomized double-blind clinical trials and a sufficiently long follow-up period are needed. Keywords: alcoholism, transcranial magnetic stimulation, therapeutics, biological psychiatry

P-28 Oscillation phase-specific modulation of cortical excitability using closed-loop transcranial magnetic stimulation

P-28 Oscillation phase-specific modulation of cortical excitability using closed-loop transcranial magnetic stimulation

Combining Transcranial Magnetic Stimulation and Deep Brain Stimulation: Current Knowledge, Relevance and Future Perspectives

Deep brain stimulation (DBS) has emerged as an invasive neuromodulation technique for the treatment of several neurological disorders, but the mechanisms underlying its effects remain partially elusive. In this context, the application of Transcranial Magnetic Stimulation (TMS) in patients treated with DBS represents an intriguing approach to investigate the neurophysiology of cortico-basal networks. Experimental studies combining TMS and DBS that have been performed so far have mainly aimed to evaluate the effects of DBS on the cerebral cortex and thus to provide insights into DBS's mechanisms of action. The modulation of cortical excitability and plasticity by DBS is emerging as a potential contributor to its therapeutic effects. Moreover, pairing DBS and TMS stimuli could represent a method to induce cortical synaptic plasticity, the therapeutic potential of which is still unexplored. Furthermore, the advent of new DBS technologies and novel treatment targets will present new research opportunities and prospects to investigate brain networks. However, the application of the combined TMS-DBS approach is currently limited by safety concerns. In this review, we sought to present an overview of studies performed by combining TMS and DBS in neurological disorders, as well as available evidence and recommendations on the safety of their combination. Additionally, we outline perspectives for future research by highlighting knowledge gaps and possible novel applications of this approach.

Language-related motor facilitation in Italian Sign Language signers.

Linguistic tasks facilitate corticospinal excitability as revealed by increased motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) in the dominant hand. This modulation of the primary motor cortex (M1) excitability may reflect the relationship between speech and gestures. It is conceivable that in healthy individuals who use a sign language this cortical excitability modulation could be rearranged. The aim of this study was to evaluate the effect of spoken language tasks on M1 excitability in a group of hearing signers. Ten hearing Italian Sign Language (LIS) signers and 16 non-signer healthy controls participated. Single-pulse TMS was applied to either M1 hand area at the baseline and during different tasks: (i) reading aloud, (ii) silent reading, (iii) oral movements, (iv) syllabic phonation and (v) looking at meaningless non-letter strings. Overall, M1 excitability during the linguistic and non-linguistic tasks was higher in LIS group compared to the control group. In LIS group, MEPs were significantly larger during reading aloud, silent reading and non-verbal oral movements, regardless the hemisphere. These results suggest that in hearing signers there is a different modulation of the functional connectivity between the speech-related brain network and the motor system.

Modulation of cortical excitability via non-invasive magnetic stimulation at kHz frequencies

Modulation of cortical excitability via non-invasive magnetic stimulation at kHz frequencies

Oscillation Phase-Specific Modulation of Cortical Excitability Using Real-Time TMS-EEG in Stroke

Oscillation Phase-Specific Modulation of Cortical Excitability Using Real-Time TMS-EEG in Stroke

A Pilot Study Leveraging Large Scale Datasets from Internet-Connected Transcranial Magnetic Stimulators: Circadian Modulation of Cortical Excitability

A Pilot Study Leveraging Large Scale Datasets from Internet-Connected Transcranial Magnetic Stimulators: Circadian Modulation of Cortical Excitability

Hierarchical Bayesian modeling of the relationship between task-related hemodynamic responses and cortical excitability.

Investigating the relationship between task-related hemodynamic responses and cortical excitability is challenging because it requires simultaneous measurement of hemodynamic responses while applying noninvasive brain stimulation. Moreover, cortical excitability and task-related hemodynamic responses are both associated with inter-/intra-subject variability. To reliably assess such a relationship, we applied hierarchical Bayesian modeling. This study involved 16 healthy subjects who underwent simultaneous Paired Associative Stimulation (PAS10, PAS25, Sham) while monitoring brain activity using functional Near-Infrared Spectroscopy (fNIRS), targeting the primary motor cortex (M1). Cortical excitability was measured by Motor Evoked Potentials (MEPs), and the motor task-related hemodynamic responses were measured using fNIRS 3D reconstructions. We constructed three models to investigate: (1) PAS effects on the M1 excitability, (2) PAS effects on fNIRS hemodynamic responses to a finger tapping task, and (3) the correlation between PAS effects on M1 excitability and PAS effects on task-related hemodynamic responses. Significant increase in cortical excitability was found following PAS25, whereas a small reduction of the cortical excitability was shown after PAS10 and a subtle increase occurred after sham. Both HbO and HbR absolute amplitudes increased after PAS25 and decreased after PAS10. The probability of the positive correlation between modulation of cortical excitability and hemodynamic activity was 0.77 for HbO and 0.79 for HbR. We demonstrated that PAS stimulation modulates task-related cortical hemodynamic responses in addition to M1 excitability. Moreover, the positive correlation between PAS modulations of excitability and hemodynamics brought insight into understanding the fundamental properties of cortical function and cortical excitability.

Embodying Language through Gestures: Residuals of Motor Memories Modulate Motor Cortex Excitability during Abstract Words Comprehension.

There is a debate about whether abstract semantics could be represented in a motor domain as concrete language. A contextual association with a motor schema (action or gesture) seems crucial to highlighting the motor system involvement. The present study with transcranial magnetic stimulation aimed to assess motor cortex excitability changes during abstract word comprehension after conditioning word reading to a gesture execution with congruent or incongruent meaning. Twelve healthy volunteers were engaged in a lexical-decision task responding to abstract words or meaningless verbal stimuli. Motor cortex (M1) excitability was measured at different after-stimulus intervals (100, 250, or 500 ms) before and after an associative-learning training where the execution of the gesture followed word processing. Results showed a significant post-training decrease in hand motor evoked potentials at an early processing stage (100 ms) in correspondence to words congruent with the gestures presented during the training. We hypothesized that traces of individual semantic memory, combined with training effects, induced M1 inhibition due to the redundancy of evoked motor representation. No modulation of cortical excitability was found for meaningless or incongruent words. We discuss data considering the possible implications in research to understand the neural basis of language development and language rehabilitation protocols.

Cerebral metabolic rate of oxygen (CMRO2) changes measured with simultaneous tDCS-MRI in healthy adults

BackgroundTranscranial direct current stimulation (tDCS) is a safe and well-tolerated noninvasive technique used for cortical excitability modulation. tDCS has been extensively investigated for its clinical applications; however further understanding of its underlying in-vivo physiological mechanisms remains a fundamental focus of current research. ObjectivesWe investigated the simultaneous effects of tDCS on cerebral blood flow (CBF), venous blood oxygenation (Yv) and cerebral metabolic rate of oxygen (CMRO2) using simultaneous MRI in healthy adults to provide a reference frame for its neurobiological mechanisms. MethodsTwenty-three healthy participants (age = 35.6 ± 15.0 years old, 10 males) completed a simultaneous tDCS-MRI session in a 3 T scanner fitted with a 64-channels head coil. A MR-compatible tDCS device was used to acquire CBF, Yv and CMRO2 at three time points: pre-, during- and post- 15 minutes of 2.0 mA tDCS on left anodal dorsolateral prefrontal cortex. ResultsDuring tDCS, CBF significantly increased (57.10 ± 8.33 mL/100g/min) from baseline (53.67 ± 7.75 mL/100g/min; p < 0.0001) and remained elevated in post-tDCS (56.79 ± 8.70 mL/100g/min). Venous blood oxygenation levels measured in pre-tDCS (60.71 ± 4.12 %) did not significantly change across the three timepoints. The resulting CMRO2 significantly increased by 5.9 % during-tDCS (175.68 ± 30.78 µmol/100g/min) compared to pre-tDCS (165.84 ± 25.32 µmol/100g/min; p = 0.0015), maintaining increased levels in post-tDCS (176.86 ± 28.58 µmol/100g/min). ConclusionstDCS has immediate effects on neuronal excitability, as measured by increased cerebral blood supply and oxygen consumption supporting increased neuronal firing. These findings provide a standard range of CBF and CMRO2 changes due to tDCS in healthy adults that may be incorporated in clinical studies to evaluate its therapeutic potential.

Adult ADHD Treatment Based on Combination of Dialectical Behavior Therapy (DBT) and Transcranial Direct Current Stimulation (tDCS) as Measured by Subjective and Objective Scales

Almost 30% of ADHD adults do not respond to standard pharmaceuticals. Transcranial direct current stimulation (tDCS) is a method for modulation of cortical excitability. On the other hand, dialectical behavioral therapy (DBT) is a cognitive-behavioral approach that might be utilized for adults with ADHD. The effects of integration of these interventions are only beginning to be explored. In the present work, we used both subjective and objective measures to investigate the effects of tDCS, DBT, and the integration of the two in treating adult ADHD symptoms. A total of 80 adults with ADHD (63 females, 17 males) participated in the study and were grouped into control, DBT, tDCS, and combined groups. Based on the observed results, the combination of DBT and tDCS was significantly effective in improving the mentioned variables compared to administration of each method in isolation. The results are discussed in terms of neurophysiological and psychological aspects of treatment methods.

Effects of Skin Stimulation on Sensory-Motor Networks Excitability: Possible Implications for Physical Training in Amyotrophic Lateral Sclerosis.

BackgroundMany different trials were assessed for rehabilitation of patients with amyotrophic lateral sclerosis (ALS), with non-unique results. Beside the effects on muscle trophism, some of the encouraging results of physical training could be ascribed to the modulation of cortical excitability, which was found hyperexcited in ALS.ObjectiveThe effects of tactile skin stimulation in the modulation of the sensory-motor integrative networks in healthy subjects were assayed through the paired associative stimulation (PAS) protocol.MethodsIn total, 15 healthy subjects were enrolled. In the standard PAS session, the average amplitude of the motor evoked potential (MEP) after 10 stimuli of transcranial magnetic stimulation (TMS) was measured at the baseline and after the PAS protocol (0, 10, 20, 30, and 60 min). In the skin stimulation session, the average amplitude of the MEP was measured before and after 10 min of skin stimulation over the hand. Subsequently, each subject underwent the PAS stimulation and the measure of the average amplitude of the MEP (0, 10, 20, 30, and 60 min).ResultsThe tactile skin stimulation on healthy subjects increases the PAS-induced sensory-motor network hyperexcitability in healthy subjects.ConclusionSkin stimulation should be avoided in the physiotherapeutic approaches for patients with ALS, given the possible hyperexciting effects on the already upmodulated sensory-motor networks. They can be taken into account for diseases characterized by downregulation of cortical and transcortical networks.

Phase-specific modulation of cortical excitability using closed-loop TMS-EEG

Phase-specific modulation of cortical excitability using closed-loop TMS-EEG

Cathodal Transcranial Direct Current Stimulation in Refractory Epilepsy: A Noninvasive Neuromodulation Therapy.

Epilepsy is a chronic disease of the brain that affects individuals of all ages and has a worldwide distribution. According to a 2006 World Health Organization report, 50 million people had epilepsy. Approximately 30% of people with epilepsy have refractory disease despite recent therapeutic developments. Consequently, new treatments are necessary. Transcranial direct current stimulation (tDCS) is a noninvasive method for cortical excitability modulation by subthreshold membrane depolarization or hyperpolarization (cathodal stimulation decreases cortical excitability, whereas anodal stimulation increases it), which has been shown to be safe, economical, and easy to use. The mechanism of action of tDCS is partially understood. Cathodal tDCS in vitro and in vivo animal studies have shown that direct current and cathodal tDCS can successfully induce suppression of epileptiform activity in EEG recordings. Cathodal tDCS has been used in heterogeneous clinical trials in pediatric and adult patients with refractory epilepsy and is well tolerated. A comprehensive review of the clinical trials based on their quality and biases shows evidence that cathodal tDCS in patients with epilepsy is potentially effective. However, additional randomized clinical trials are needed with other etiologies, special populations, additional concomitants therapies, long-term follow-up, and new parameters of stimulation.

Intermittent Theta-Burst Stimulation Over the DorsoLateral PreFrontal Cortex (DLPFC) in Healthy Subjects Produces No Cumulative Effect on Cortical Excitability.

Background: Intermittent Theta Burst Stimulation (iTBS) is a design of repetitive Transcranial Magnetic Stimulation (rTMS) and could be a candidate to replace rTMS in the treatment of depression, thanks to its efficacy, shorter duration, and ease of use. The antidepressant mechanism of iTBS, and whether this mechanism is mediated by a modulation of cortical excitability, remains unknown.Methods: Using a randomized double-blind, sham-controlled trial, 30 healthy volunteers received either iTBS or a sham treatment targeting the left DorsoLateral PreFrontal Cortex (L-DLPFC), twice a day over 5 consecutive days. Cortical excitability was measured before and after the 5 days of stimulation.Results: No difference in cortical excitability was observed between active or sham iTBS.Conclusion: Our study does not support any effect on cortical excitability of repetitive iTBS targeting the L-DLPFC.

Cathodal Transcranial Direct Current Stimulation (tDCS) Applied to the Left Premotor Cortex Interferes with Explicit Reproduction of a Motor Sequence.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that allows the modulation of cortical excitability. TDCS effects can outlast the stimulation period presumably due to changes of GABA concentration which play a critical role in use-dependent plasticity. Consequently, tDCS and learning-related synaptic plasticity are assumed to share common mechanisms. Motor sequence learning has been related to activation changes within a cortico-subcortical network and findings from a meta-analysis point towards a core network comprising the cerebellum as well as the primary motor (M1) and the dorsolateral premotor cortex (dPMC). The latter has been particularly related to explicit motor learning by means of brain imaging techniques. We here test whether tDCS applied to the left dPMC affects the acquisition and reproduction of an explicitly learned motor sequence. To this end, 18 healthy volunteers received anodal, cathodal and sham tDCS to the left dPMC and were then trained on a serial reaction time task (SRTT) with their right hand. Immediately after the training and after overnight sleep, reproduction of the learned sequence was tested by means of reaction times as well as explicit recall. Regression analyses suggest that following cathodal tDCS reaction times at the end of the SRTT training-block explained a significant proportion of the number of correctly reported sequence items after overnight sleep. The present data suggest the left premotor cortex as one possible target for the application of non-invasive brain stimulation techniques in explicit motor sequence learning with the right hand.

Anodal transcranial direct current stimulation could modulate cortical excitability reflecting central cholinergic dysfunction

Background: Anodal transcranial direct current stimulation (tDCS) is known for accentuate excitability in simulating area. We aim to investigate modulation of cortical excitability after anodal tDCS stimulation using various transcranial magnetic stimulation parameters.