Bilateral Transcranial Direct Current Stimulation Reshapes Resting-State Brain Networks: A Magnetoencephalography Assessment

Pellegrino, Giovanni; Maran, Matteo; Turco, Cristina; Weis, Luca; Pino, Giovanni Di; Piccione, Francesco; Arcara, Giorgio

doi:10.1155/2018/2782804

Cited by 31 publications

(21 citation statements)

References 73 publications

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“…However, tDCS‐cerebral cortex interaction is far more complex for at least the four following reasons. Firstly, in addition to the well‐known effect on cortical excitability, tDCS has an impact on several domains of brain function, including oscillatory activity, brain synchrony and hemodynamic processes (Herrmann, Rach, Neuling, & Strüber, ; Hoy, Bailey, Arnold, & Fitzgerald, ; Lang et al, ; Notturno, Marzetti, Pizzella, Uncini, & Zappasodi, ; Pellegrino et al, ; Stagg & Nitsche, ). Secondly, tDCS has remote effects in areas distant from the cortex underneath the stimulating electrodes.…”

Section: Introductionmentioning

confidence: 99%

“…Remote effects have been attributed to interactions between the targeted brain area and connected areas forming a functional network (Fischer et al, 2017;Fox et al, 2014;Giambattistelli et al, 2014;Lindenberg, Nachtigall, Meinzer, Sieg, & Flöel, 2013;Peña-Gómez et al, 2012). tDCS-related remote effects have been demonstrated with a number of different read-outs of regional brain function, including BOLD signal (Polanía, Paulus, & Nitsche, 2012), measures of cortical excitability (Boros, Poreisz, Münchau, Paulus, & Nitsche, 2008;Lang, Nitsche, Paulus, Rothwell, & Lemon, 2004) and signatures of cortical activity and rhythms measured by electroencephalography and magnetoencephalography (Notturno et al, 2014;Pellegrino, Maran, et al, 2018). Thirdly, tDCS stimulation is a bipolar technique and its effects depend on the activity and position of both anode and cathode.…”

Section: Introductionmentioning

confidence: 99%

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Transcranial direct current stimulation over the sensory‐motor regions inhibits gamma synchrony

Pellegrino

Arcara

Pino

et al. 2019

Human Brain Mapping

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Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique able to induce plasticity phenomena. Although tDCS application has been spreading over a variety of neuroscience domains, the mechanisms by which the stimulation acts are largely unknown. We investigated tDCS effects on cortical gamma synchrony, which is a crucial player in cortical function. We performed a randomized, sham‐controlled, double‐blind study on healthy subjects, combining tDCS and magnetoencephalography. By driving brain activity via 40 Hz auditory stimulation during magnetoencephalography, we experimentally tuned cortical gamma synchrony and measured it before and after bilateral tDCS of the primary sensory‐motor hand regions (anode left, cathode right). We demonstrated that the stimulation induces a remarkable decrease of gamma synchrony (13 out of 15 subjects), as measured by gamma phase at 40 Hz. tDCS has strong remote effects, as the cortical region mostly affected was located far away from the stimulation site and covered a large area of the right centro‐temporal cortex. No significant differences between stimulations were found for baseline gamma synchrony, as well as early transient auditory responses. This suggests a specific tDCS effect on externally driven gamma synchronization. This study sheds new light on the effect of tDCS on cortical function showing that the net effect of the stimulation on cortical gamma synchronization is an inhibition.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transcranial direct current stimulation over the sensory‐motor regions inhibits gamma synchrony

Pellegrino

Arcara

Pino

et al. 2019

Human Brain Mapping

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“…Speci cally, in our study the reduction of beta occurred for participants who already showed a higher level of beta power before the administration of Conventional tDCS. The inhibition of beta induced by anodal tDCS is not unusual in the literature 35,36 , despite previous evidence showing an opposite pattern, namely an increase of beta power 28 .…”

Section: Discussionmentioning

confidence: 63%

Conventional vs. High-definition tDCS: A Comparison of Neurophysiological and Behavioural Effects

Masina¹,

Arcara²,

Galletti³

et al. 2020

Preprint

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High-definition transcranial direct current stimulation (HD-tDCS) seems to overcome a drawback of Conventional tDCS: the wide-spread diffusion of the electric field. Nevertheless, most of the differences that characterise the two techniques are based on mathematical simulations and not on real, behavioural and neurophysiological, data. The study aims to compare Conventional and HD-tDCS, investigating differences both at a behavioural level, in terms of dexterity performance, and a neurophysiological level, as modifications of alpha and beta power as measured with EEG. Thirty participants took part in three sessions, one for each montage: Conventional tDCS, HD-tDCS, and sham. In all the conditions, the anode was placed over C4, while the cathode/s placed according to the montage. At baseline, during, and after each stimulation condition, dexterity was assessed with a Finger Tapping Task. In addition, resting-state EEG was recorded at baseline and after the stimulation. Power spectrum density was calculated, selecting two frequency bands: alpha (8–12 Hz) and beta (18–22 Hz). Linear mixed effect models (LMMs) were used to analyse the modulation induced by tDCS. To evaluate differences among the montages and consider state-dependency phenomenon, the post-stimulation measurements were covariate-adjusted for baseline levels. We observed that HD-tDCS induced an alpha power reduction in participants with lower alpha. Conversely, Conventional tDCS induced a beta power reduction in participants with higher beta at baseline. Furthermore, data suggested a positive behavioural effect of HD-tDCS on dexterity in participants with lower beta at baseline. Conventional and HD-tDCS distinctively modulated cortical activity. The study highlights the importance of considering state-dependency to determine the effects of tDCS on individuals.

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“…PLV owns a good time resolution and provides insight on the synchronization of fast changing electrophysiological dynamic. High PLV indicates higher synchronization (23–27). We measured PLV for all possible channel combinations and averaged to obtain a measure of global connectivity.…”

Section: Methodsmentioning

confidence: 99%

Eslicarbazepine Acetate Modulates EEG Activity and Connectivity in Focal Epilepsy

et al. 2018

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Introduction: Eslicarbazepine acetate (ESL) is an antiepileptic drug approved as monotherapy or add-on for the treatment of epilepsy with seizures of focal onset. ESL owns a good profile in terms of efficacy and tolerability, but its effects on EEG activity and connectivity are unknown. The purpose of this study was to investigate EEG activity and connectivity changes after ESL treatment in persons with focal epilepsy (PFE).Material and Methods: We performed a multicentre, longitudinal, retrospective, quantitative EEG study on a population of 22 PFE, and a group of 40 controls. We investigated the ESL-related changes of EEG power spectral activity and global connectivity [phase locking value (PLV), amplitude envelope correlation (AEC) and amplitude envelope correlation of orthogonalized signals (Ortho-AEC)] for standard frequency bands (delta to gamma). Seizure frequency was evaluated to assess ESL efficacy in our cohort.Results: ESL significantly enhanced both global power spectral density and connectivity for all frequency bands, similarly for all connectivity measures. When compared to the control group, Post-ESL power was significantly higher in theta and gamma band. Pre-ESL connectivity values were significantly lower than control for all frequency bands. Post-ESL connectivity increased and the gap between the two groups was no longer significant. ESL induced a 52.7 ± 41.1% reduction of seizure frequency, with 55% of clinical responders (reduction of seizures ≥50%).Discussion: ESL therapy induces significant enhancement of brain activity and connectivity. Post-ESL connectivity profile of epilepsy patients was similar to the one of healthy controls.

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Bilateral Transcranial Direct Current Stimulation Reshapes Resting-State Brain Networks: A Magnetoencephalography Assessment

Cited by 31 publications

References 73 publications

Transcranial direct current stimulation over the sensory‐motor regions inhibits gamma synchrony

Transcranial direct current stimulation over the sensory‐motor regions inhibits gamma synchrony

Conventional vs. High-definition tDCS: A Comparison of Neurophysiological and Behavioural Effects

Eslicarbazepine Acetate Modulates EEG Activity and Connectivity in Focal Epilepsy

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