Entrainment of brain oscillations by transcranial alternating current stimulation.

By Randolph F. Helfrich, Till R. Schneider, Stefan Rach, S. Trautmann-Lengsfeld, Andreas K. Engel, Christoph S. Herrmann. Current Biology, 2014

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Novel methods for neuronal entrainment [1-4] provide the unique opportunity to modulate perceptually relevant brain oscillations [5, 6] in a frequency-specific manner and to study their functional impact on distinct cognitive functions. Recently, evidence has emerged that tACS (transcranial alternating current stimulation) can modulate cortical oscillations [7-9]. However, the study of electrophysiological effects has been hampered so far by the absence of concurrent electroencephalogram (EEG) recordings. Here, we applied 10 Hz tACS to the parieto-occipital cortex and utilized simultaneous EEG recordings to study neuronal entrainment during stimulation. We pioneer a novel approach for simultaneous tACS-EEG recordings and successfully separate stimulation artifacts from ongoing and event-related cortical activity. Our results reveal that 10 Hz tACS increases parieto-occipital alpha activity and synchronizes cortical oscillators with similar intrinsic frequencies to the entrainment frequency. Additionally, we demonstrate that tACS modulates target detection performance in a phase-dependent fashion highlighting the causal role of alpha oscillations for visual perception.

Subfields: Cognitive Neuroscience, Neurology

View Paper: https://www.semanticscholar.org/paper/7214c7a297663ccde89baa05b6ff79ee08217552

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Citations in the corpus

Distinct contributions of low- and high-frequency neural oscillations to speech comprehension (2017, background): “There are glimpses of evidence that neural entrainment could last for a few cycles after visual/tACS stimulation (Helfrich et al., 2014; Spaak, de Lange, & Jensen, 2014; Zaehle, Rach, & Herrmann, 2010) but additional research is needed to test whether this remising oscillatory response has…”
Questions and controversies in the study of time-varying functional connectivity in resting fMRI (2020, neutral): “…rapidly, and recent years have seen the development of methods such as transcranial electrical stimulation—tACS (Ali, Sellers, & Frohlich, 2013; Helfrich et al., 2014) and tDCS (Keeser et al., 2011; Polania, Nitsche, & Paulus, 2011; Polania, Paulus, & Nitsche, 2012; Sehm et al., 2012)—and…”
Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines (2017, methodology): “Recording electrophysiological data during stimulation requires methods for artifact elimination (Helfrich et al. , 2014, Neuling et al. , 2015).”
A technical guide to tDCS, and related non-invasive brain stimulation tools (2015, background): “In addition, the frequency of an EEG oscillation can be modulated towards the frequency of tACS if the frequencies of tACS are close to the intrinsic frequency of the EEG (Helfrich et al., 2014a).”
Combining non-invasive transcranial brain stimulation with neuroimaging and electrophysiology: Current approaches and future perspectives (2016, neutral): “…of these artefacts usually requires thorough andmanually guided offline analysis involving spatial filter and template subtraction techniques (Helfrich et al., 2014; Hernandez-Pavon et al., 2012; Ilmoniemi and Kicic, 2010; Marshall et al., 2015a; Neuling et al., 2015; Siebner et al., 2009a;…”
Online and offline effects of parietal 10 Hz repetitive transcranial magnetic stimulation on working memory in healthy controls (2024, methodology): “…number of studies (either using rTMS-EEG, Emrich et al., 2017; Hamidi et al., 2009; Johnson et al., 2010; Sauseng et al., 2009; or using tACS-EEG, Helfrich et al., 2014; Vossen et al., 2015) have reported that online brain stimulation with alpha frequency could entrain alpha oscillation, and…”
Modulating Individual Alpha Frequency through Short-Term Neurofeedback for Cognitive Enhancement in Healthy Young Adults (2023, methodology): “The modulation of individual alpha activities has been explored through various techniques, including neurofeedback [26–35], repetitive transcranial magnetic stimulation (rTMS) [36–38], transcranial alternative current stimulation (tACS) [39], and rhythmic visual stimulus [40].”