scholarly journals Exploring parameters of gamma transcranial alternating current stimulation (tACS) and full‐spectrum transcranial random noise stimulation (tRNS) on human pharyngeal cortical excitability

2021 ◽  
Author(s):  
Mengqing Zhang ◽  
Ivy Cheng ◽  
Ayodele Sasegbon ◽  
Zulin Dou ◽  
Shaheen Hamdy
Keyword(s):  
Cortical Excitability ◽  
Random Noise ◽  
Alternating Current ◽  
Full Spectrum ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

scholarly journals Online and offline effects of transcranial alternating current stimulation of the primary motor cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Pozdniakov ◽  
Alicia Nunez Vorobiova ◽  
Giulia Galli ◽  
Simone Rossi ◽  
Matteo Feurra
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Random Noise ◽  
Single Pulse ◽  
Alternating Current ◽  
Online Application ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

AbstractTranscranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows interaction with endogenous cortical oscillatory rhythms by means of external sinusoidal potentials. The physiological mechanisms underlying tACS effects are still under debate. Whereas online (e.g., ongoing) tACS over the motor cortex induces robust state-, phase- and frequency-dependent effects on cortical excitability, the offline effects (i.e. after-effects) of tACS are less clear. Here, we explored online and offline effects of tACS in two single-blind, sham-controlled experiments. In both experiments we used neuronavigated transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) as a probe to index changes of cortical excitability and delivered M1 tACS at 10 Hz (alpha), 20 Hz (beta) and sham (30 s of low-frequency transcranial random noise stimulation; tRNS). Corticospinal excitability was measured by single pulse TMS-induced motor evoked potentials (MEPs). tACS was delivered online in Experiment 1 and offline in Experiment 2. In Experiment 1, the increase of MEPs size was maximal with the 20 Hz stimulation, however in Experiment 2 neither the 10 Hz nor the 20 Hz stimulation induced tACS offline effects. These findings support the idea that tACS affects cortical excitability only during online application, at least when delivered on the scalp overlying M1, thereby contributing to the development of effective protocols that can be applied to clinical populations.

scholarly journals Transkranielle elektrische Hirnstimulationsverfahren zur Behandlung der Negativsymptomatik bei Schizophrenie

2021 ◽  
Author(s):  
Nikolas Haller ◽  
Alkomiet Hasan ◽  
Frank Padberg ◽  
Wolfgang Strube ◽  
Leandro da Costa Lane Valiengo ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Random Noise ◽  
Alternating Current ◽  
Direct Current Stimulation ◽  
Transkranielle Gleichstromstimulation ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

ZusammenfassungÜber die letzten Jahre entwickelten sich Neuromodulationsverfahren zu einer dritten Säule neben Pharmakotherapie und Psychotherapie in der Behandlung psychischer Erkrankungen. Besonders in der Behandlung von Menschen mit einer Schizophrenie könnten Hirnstimulationsverfahren eine Alternative oder Ergänzung zu den etablierten Therapiestrategien darstellen. Die meist vorhandenen Positivsymptome können zumeist mit Antipsychotika adäquat behandelt werden. Gerade bei Patienten mit Schizophrenie besitzen jedoch Negativsymptome einen überdauernden Krankheitswert und beeinflussen den Verlauf durch globale Antriebsverarmung und beeinträchtigte Kognition im alltäglichen Leben negativ. Dieser Übersichtsartikel stellt eine Zusammenfassung über die verschiedenen nichtinvasiven Hirnstimulationsverfahren transkranielle Gleichstromstimulation (transcranial direct current stimulation, tDCS), Wechselstromstimulation (transcranial alternating current stimulation, tACS) sowie Rauschstromstimulation (transcranial random noise stimulation, tRNS) zur Behandlung der Negativsymptomatik bei Schizophrenie dar. Die neuen transkraniellen Hirnstimulationsverfahren könnten dabei helfen, gestörte neuronale Vernetzungen wieder herzustellen und die Konnektivität vor allem der dorsolateralen präfrontalen Anteile des Kortex zu verbessern. Einige Studien weisen auf eine Verbesserung der Negativsymptome durch Behandlung mit tDCS, tACS bzw. tRNS hin und könnten so neue Therapiemöglichkeiten in der Behandlung der Schizophrenie darstellen.

scholarly journals Transcranial Alternating Current and Random Noise Stimulation: Possible Mechanisms

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Andrea Antal ◽  
Christoph S. Herrmann
Keyword(s):  
Random Noise ◽  
Animal Experiments ◽  
Alternating Current ◽  
Brain Oscillations ◽  
Physiological Mechanisms ◽  
Fine Grained ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation ◽  
Network Simulations ◽  
And Behavior

Background. Transcranial alternating current stimulation (tACS) is a relatively recent method suited to noninvasively modulate brain oscillations. Technically the method is similar but not identical to transcranial direct current stimulation (tDCS). While decades of research in animals and humans has revealed the main physiological mechanisms of tDCS, less is known about the physiological mechanisms of tACS.Method. Here, we review recent interdisciplinary research that has furthered our understanding of how tACS affects brain oscillations and by what means transcranial random noise stimulation (tRNS) that is a special form of tACS can modulate cortical functions.Results. Animal experiments have demonstrated in what way neurons react to invasively and transcranially applied alternating currents. Such findings are further supported by neural network simulations and knowledge from physics on entraining physical oscillators in the human brain. As a result, fine-grained models of the human skull and brain allow the prediction of the exact pattern of current flow during tDCS and tACS. Finally, recent studies on human physiology and behavior complete the picture of noninvasive modulation of brain oscillations.Conclusion. In future, the methods may be applicable in therapy of neurological and psychiatric disorders that are due to malfunctioning brain oscillations.

scholarly journals A specific phase of transcranial alternating current stimulation at the β frequency boosts repetitive paired-pulse TMS-induced plasticity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hisato Nakazono ◽  
Katsuya Ogata ◽  
Akinori Takeda ◽  
Emi Yamada ◽  
Shinichiro Oka ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Alternating Current ◽  
Dependent Manner ◽  
Synaptic Efficacy ◽  
Paired Pulse ◽  
Transcranial Alternating Current Stimulation ◽  
In Trans ◽  
Specific Phase

AbstractTranscranial alternating current stimulation (tACS) at 20 Hz (β) has been shown to modulate motor evoked potentials (MEPs) when paired with transcranial magnetic stimulation (TMS) in a phase-dependent manner. Repetitive paired-pulse TMS (rPPS) with I-wave periodicity (1.5 ms) induced short-lived facilitation of MEPs. We hypothesized that tACS would modulate the facilitatory effects of rPPS in a frequency- and phase-dependent manner. To test our hypothesis, we investigated the effects of combined tACS and rPPS. We applied rPPS in combination with peak or trough phase tACS at 10 Hz (α) or β, or sham tACS (rPPS alone). The facilitatory effects of rPPS in the sham condition were temporary and variable among participants. In the β tACS peak condition, significant increases in single-pulse MEPs persisted for over 30 min after the stimulation, and this effect was stable across participants. In contrast, β tACS in the trough condition did not modulate MEPs. Further, α tACS parameters did not affect single-pulse MEPs after the intervention. These results suggest that a rPPS-induced increase in trans-synaptic efficacy could be strengthened depending on the β tACS phase, and that this technique could produce long-lasting plasticity with respect to cortical excitability.

Comparatively weak after-effects of transcranial alternating current stimulation (tACS) on cortical excitability in humans

2008 ◽  
Vol 1 (2) ◽  
pp. 97-105 ◽  
Author(s):  
Andrea Antal ◽  
Klára Boros ◽  
Csaba Poreisz ◽  
Leila Chaieb ◽  
Daniella Terney ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Alternating Current ◽  
After Effects ◽  
Transcranial Alternating Current Stimulation

Sham transcranial electrical stimulation and its effects on corticospinal excitability: a systematic review and meta-analysis

2018 ◽  
Vol 29 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Thusharika D. Dissanayaka ◽  
Maryam Zoghi ◽  
Michael Farrell ◽  
Gary F. Egan ◽  
Shapour Jaberzadeh
Keyword(s):  
Systematic Review ◽  
Electrical Stimulation ◽  
Meta Analysis ◽  
Random Noise ◽  
Corticospinal Excitability ◽  
Transcranial Electrical Stimulation ◽  
Placebo Effects ◽  
Randomized Controlled ◽  
Transcranial Random Noise Stimulation ◽  
Transcranial Alternating Current Stimulation

AbstractSham stimulation is used in randomized controlled trials (RCTs) to assess the efficacy of active stimulation and placebo effects. It should mimic the characteristics of active stimulation to achieve blinding integrity. The present study was a systematic review and meta-analysis of the published literature to identify the effects of sham transcranial electrical stimulation (tES) – including anodal and cathodal transcranial direct current stimulation (a-tDCS, c-tDCS), transcranial alternating current stimulation (tACS), transcranial random noise stimulation (tRNS) and transcranial pulsed current stimulation (tPCS) – on corticospinal excitability (CSE), compared to baseline in healthy individuals. Electronic databases – PubMed, CINAHL, Scopus, Science Direct and MEDLINE (Ovid) – were searched for RCTs of tES from 1990 to March 2017. Thirty RCTs were identified. Using a random-effects model, meta-analysis of a-tDCS, c-tDCS, tACS, tRNS and tPCS studies showed statistically non-significant pre-post effects of sham interventions on CSE. This review found evidence for statically non-significant effects of sham tES on CSE.

Changes in TMS measures of cortical excitability induced by transcranial direct and alternating current stimulation

2021 ◽  
Author(s):  
Michael A. Nitsche ◽  
Walter Paulus ◽  
Gregor Thut
Keyword(s):  
Brain Stimulation ◽  
Cortical Excitability ◽  
Brain Activity ◽  
Alternating Current ◽  
Transcranial Electrical Stimulation ◽  
Electrical Currents ◽  
After Effects ◽  
Brain Physiology ◽  
Transcranial Alternating Current Stimulation ◽  
Oscillatory Brain Activity

Brain stimulation with weak electrical currents (transcranial electrical stimulation, tES) is known already for about 60 years as a technique to generate modifications of cortical excitability and activity. Originally established in animal models, it was developed as a noninvasive brain stimulation tool about 20 years ago for application in humans. Stimulation with direct currents (transcranial direct current stimulation, tDCS) induces acute cortical excitability alterations, as well as neuroplastic after-effects, whereas stimulation with alternating currents (transcranial alternating current stimulation, tACS) affects primarily oscillatory brain activity but has also been shown to induce neuroplasticity effects. Beyond their respective regional effects, both stimulation techniques have also an impact on cerebral networks. Transcranial magnetic stimulation (TMS) has been pivotal to helping reveal the physiological effects and mechanisms of action of both stimulation techniques for motor cortex application, but also for stimulation of other areas. This chapter will supply the reader with an overview about the effects of tES on human brain physiology, as revealed by TMS.

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