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

@article{citeulike:3109593, abstract = {Objective Interference with brain rhythms by noninvasive transcranial stimulation that uses weak transcranial alternating current may reveal itself to be a new tool for investigating cortical mechanisms currently unresolved. Here, we aim to extend transcranial direct current stimulation (tDCS) techniques to transcranial alternating current stimulation (tACS).Background Parameters such as electrode size and position were taken from those used in previous tDCS studies.Methods Motor evoked potentials (MEPs) revealed by transcranial magnetic stimulation (TMS), electroencephalogram (EEG)-power, and reaction times measured in a motor implicit learning task, were analyzed to detect changes in cortical excitability after 2-10 minutes of AC stimulation and sinusoidal DC stimulation (tSDCS) by using 1, 10, 15, 30, and 45 Hz and sham stimulation over the primary motor cortex in 50 healthy subjects (eight-16 subjects in each study).Results A significantly improved implicit motor learning was observed after 10 Hz AC stimulation only. No significant changes were observed in any of the analyzed frequency bands of EEG and with regard to the MEP amplitudes after AC or tSDCS stimulation. Similarly, if the anodal or cathodal DC stimulation was superimposed on 5, 10, and 15 Hz AC stimulation, the MEP amplitudes did not change significantly.Conclusions Transcranial application of weak AC current may appear to be a tool for basic and clinical research in diseases with altered EEG activity. However, its effect seems to be weaker than tDCS stimulation, at least in the present context of stimulus intensity and duration. Further studies are required to extend cautiously the safety range and uncover its influence on neuronal circuitries.}, author = {Antal, Andrea and Boros, Kl\'{a}ra and Poreisz, Csaba and Chaieb, Leila and Terney, Daniella and Paulus, Walter}, citeulike-article-id = {3109593}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.brs.2007.10.001}, citeulike-linkout-1 = {http://www.sciencedirect.com/science/article/B8JBG-4R8KSB3-C/2/cfa8cbdf2b48758978793d59a0a1f5c8}, doi = {10.1016/j.brs.2007.10.001}, journal = {Brain Stimulation}, keywords = {tacs, tdcs}, month = {April}, number = {2}, pages = {97--105}, posted-at = {2008-08-11 21:14:26}, priority = {2}, title = {Comparatively weak after-effects of transcranial alternating current stimulation (tACS) on cortical excitability in humans}, url = {http://dx.doi.org/10.1016/j.brs.2007.10.001}, volume = {1}, year = {2008} }

TY - JOUR ID - citeulike:3109593 L3 - citeulike-article-id:3109593 N2 - Objective Interference with brain rhythms by noninvasive transcranial stimulation that uses weak transcranial alternating current may reveal itself to be a new tool for investigating cortical mechanisms currently unresolved. Here, we aim to extend transcranial direct current stimulation (tDCS) techniques to transcranial alternating current stimulation (tACS).Background Parameters such as electrode size and position were taken from those used in previous tDCS studies.Methods Motor evoked potentials (MEPs) revealed by transcranial magnetic stimulation (TMS), electroencephalogram (EEG)-power, and reaction times measured in a motor implicit learning task, were analyzed to detect changes in cortical excitability after 2-10 minutes of AC stimulation and sinusoidal DC stimulation (tSDCS) by using 1, 10, 15, 30, and 45 Hz and sham stimulation over the primary motor cortex in 50 healthy subjects (eight-16 subjects in each study).Results A significantly improved implicit motor learning was observed after 10 Hz AC stimulation only. No significant changes were observed in any of the analyzed frequency bands of EEG and with regard to the MEP amplitudes after AC or tSDCS stimulation. Similarly, if the anodal or cathodal DC stimulation was superimposed on 5, 10, and 15 Hz AC stimulation, the MEP amplitudes did not change significantly.Conclusions Transcranial application of weak AC current may appear to be a tool for basic and clinical research in diseases with altered EEG activity. However, its effect seems to be weaker than tDCS stimulation, at least in the present context of stimulus intensity and duration. Further studies are required to extend cautiously the safety range and uncover its influence on neuronal circuitries. IS - 2 JF - Brain Stimulation EP - 105 TI - Comparatively weak after-effects of transcranial alternating current stimulation (tACS) on cortical excitability in humans VL - 1 SP - 97 KW - tacs KW - tdcs AU - Antal, Andrea AU - Boros, Klára AU - Poreisz, Csaba AU - Chaieb, Leila AU - Terney, Daniella AU - Paulus, Walter PY - 2008/04// UR - http://dx.doi.org/10.1016/j.brs.2007.10.001 ER -