Inhibition of motor cortex excitability with 15Hz transcranial alternating current stimulation (tACS)

Zaghi, Soroush; Rezende, Larissa de Freitas; Oliveira, Luiz Marcellino de; El-Nazer, Rasheda; Menning, Sanne; Tadini, L.; Fregni, Felipe

doi:10.1016/j.neulet.2010.05.060

Cited by 64 publications

(42 citation statements)

References 17 publications

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“…The waveform of the stimulation changes cyclically over time, with either sinus pulses or square pulses that penetrate the skull through the electrodes placed over the surface of the scalp or are transmitted through the eye and optic nerve to the brain (19, 20). The effects of tACS at the neuronal level highly depend on the parameters used, i.e., current density, frequency range, electrode size, and the location of the stimulation electrode (21).…”

Section: Discussionmentioning

confidence: 99%

Transcranial Alternating Current Stimulation: A Potential Risk for Genetic Generalized Epilepsy Patients (Study Case)

et al. 2016

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Transcranial alternating current stimulation (tACS) is a re-emergent neuromodulation technique that consists in the external application of oscillating electrical currents that induces changes in cortical excitability. We present the case of a 16-year-old female with pharmaco-resistant juvenile myoclonic epilepsy to 3 antiepileptic’s drugs characterized by 4 myoclonic and 20 absence seizures monthly. She received tACS at 1 mA at 3 Hz pulse train during 60 min over Fp1–Fp2 (10–20 EEG international system position) during 4 consecutive days using an Endeavor™ IOM Systems device® (Natus Medical Incorporated, Middleton, WI, USA). At the 1-month follow-up, she reported a 75% increase in seizures frequency (only myoclonic and tonic–clonic events) and developed a 24-h myoclonic status epilepticus that resolved with oral clonazepam and intravenous valproate. At the 2-month follow-up, the patient reported a 15-day seizure-free period.

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Section: Discussionmentioning

confidence: 99%

Transcranial Alternating Current Stimulation: A Potential Risk for Genetic Generalized Epilepsy Patients (Study Case)

et al. 2016

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“…TACS in the β-range (20 Hz) was delivered for 10 min. For sham, stimulation with 20 Hz was applied for 30 s to induce the typical tingling sensation (Zaghi et al, 2010b; Schutter and Hortensius, 2011; Wach et al, 2013). During tACS or sham, participants were asked to stay awake and relaxed in a seated position.…”

Section: Methodsmentioning

confidence: 99%

“…Zaehle et al (2010) proposed that endogenous oscillations could be enhanced by tACS at a matching frequency. Indeed, tACS applied in specific frequency bands (e.g., α, β or θ band) over primary motor cortex (M1) or the visual cortex modulates cortical excitability within the stimulated hemisphere by modulating natural brain rhythms (Zaghi et al, 2010a,b). …”

Section: Introductionmentioning

confidence: 99%

Transcranial Alternating Current Stimulation at Beta Frequency: Lack of Immediate Effects on Excitation and Interhemispheric Inhibition of the Human Motor Cortex

Rjosk

Kaminski

Hoff

et al. 2016

Front. Hum. Neurosci.

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Transcranial alternating current stimulation (tACS) is a form of noninvasive brain stimulation and is capable of influencing brain oscillations and cortical networks. In humans, the endogenous oscillation frequency in sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during maintenance of tonic motor output and seems to play a role in interhemispheric coordination of movements. Previous studies showed that tACS applied in specific frequency bands over primary motor cortex (M1) or the visual cortex modulates cortical excitability within the stimulated hemisphere. However, the particular impact remains controversial because effects of tACS were shown to be frequency, duration and location specific. Furthermore, the potential of tACS to modulate cortical interhemispheric processing, like interhemispheric inhibition (IHI), remains elusive. Transcranial magnetic stimulation (TMS) is a noninvasive and well-tolerated method of directly activating neurons in superficial areas of the human brain and thereby a useful tool for evaluating the functional state of motor pathways. The aim of the present study was to elucidate the immediate effect of 10 min tACS in the β-frequency band (20 Hz) over left M1 on IHI between M1s in 19 young, healthy, right-handed participants. A series of TMS measurements (motor evoked potential (MEP) size, resting motor threshold (RMT), IHI from left to right M1 and vice versa) was performed before and immediately after tACS or sham using a double-blinded, cross-over design. We did not find any significant tACS-induced modulations of intracortical excitation (as assessed by MEP size and RMT) and/or IHI. These results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of modulating immediate brain activity or inhibition. Further studies are needed to elucidate potential aftereffects of 20 Hz tACS as well as frequency-specific effects of tACS on intracortical excitation and IHI.

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“…tACS effects also seem to depend on the applied frequency, but the picture evolving with regard to frequency is less clear and results are in some cases contradictory. In other words, lower frequencies (1-45 Hz) did not reproducibly alter excitability in one study (Antal, Boros et al, 2008), but another study showed a decreasing effect of 15 Hz (Zaghi et al, 2010). Wach et al, (2012) showed an enhancing effect of 10 Hz and decreasing effect at 20 Hz.…”

Section: Tes and Motor Cortical Excitabilitymentioning

confidence: 87%

Motor System

Reis

Prichard

Fritsch

2014

The Stimulated Brain

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Inhibition of motor cortex excitability with 15Hz transcranial alternating current stimulation (tACS)

Cited by 64 publications

References 17 publications

Transcranial Alternating Current Stimulation: A Potential Risk for Genetic Generalized Epilepsy Patients (Study Case)

Transcranial Alternating Current Stimulation: A Potential Risk for Genetic Generalized Epilepsy Patients (Study Case)

Transcranial Alternating Current Stimulation at Beta Frequency: Lack of Immediate Effects on Excitation and Interhemispheric Inhibition of the Human Motor Cortex

Motor System

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