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. 2018 Jun 25:12:428.
doi: 10.3389/fnins.2018.00428. eCollection 2018.

Multi-Electrode Alpha tACS During Varying Background Tasks Fails to Modulate Subsequent Alpha Power

Tomer Fekete  1 , Andrey R Nikolaev  1 , Floris De Knijf  2 , Aleksandra Zharikova  1 , Cees van Leeuwen  1
Affiliations

Multi-Electrode Alpha tACS During Varying Background Tasks Fails to Modulate Subsequent Alpha Power

Tomer Fekete et al. Front Neurosci. .

Abstract

Transcranial alternating-current stimulation (tACS) for entraining alpha activity holds potential for influencing mental function, both in laboratory and clinical settings. While initial results of alpha entrainment are promising, questions remain regarding its translational potential-namely if tACS alpha entrainment is sufficiently robust to context and to what extent it can be upscaled to multi-electrode arrangements needed to direct currents into precise brain loci. We set out to explore these questions by administering alternating current through a multi-electrode montage (mtACS), while varying background task. A multi-electrode analog of previously employed anterior/posterior stimulation failed to replicate the reported alpha entrainment, suggesting that further work is required to understand the scope of applicability of tACS alpha entrainment.

Keywords: EEG; alpha rhythm; alternating; multi electrode stimulation; transcranial current stimulation.

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Figures

Figure 1
Figure 1
The mtACS paradigm. Stimulation frequency was determined as peak alpha for the spectrogram averaged over all electrodes. The anterior electrodes (C3,4 and F3,4) were phase locked, and in anti-phase to the posterior electrodes (O1,2 and P3,4). This in essence recreated the stimulation paradigm employed in (Neuling et al., ; Helfrich et al., 2014a) albeit in the multi-electrode scenario.
Figure 2
Figure 2
Effects of stimulation. (A,B) The average (across participants and electrodes) spectrograms before (gray) and after (red) stimulation for mtACS stimulation and sham. (C,D) Same as the above after normalizing spectra to power in the 1–40 Hz band. Envelope represents SE.
Figure 3
Figure 3
Effects of stimulation. (A) Finite element modeling of induced electrical field (EF). Left: EF for the paradigm of Neuling et al(Neuling et al., 2013). Right: the result for our mtACS paradigm. (B) the average field strength (mean ± SD) under the recording electrodes in both studies. (C) Alpha modulation as a function of injected current. (gray – individual electrodes, red – mean ± SD modulation (across electrodes and subjects) per current level).
Figure 4
Figure 4
Alpha LRTC aftereffects. Results are presented as mean ± SE. Post-hoc p-values were FDR corrected. *p < 0.05, ***p < 0.001.
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References

    1. Başar E. (2012). A review of alpha activity in integrative brain function: fundamental physiology, sensory coding, cognition and pathology. Int. J. Psychophysiol. 86, 1–24. 10.1016/j.ijpsycho.2012.07.002 - DOI - PubMed
    1. Cantero J. L., Atienza M., Salas R. M. (2002). Human alpha oscillations in wakefulness, drowsiness period, and REM sleep: different electroencephalographic phenomena within the alpha band. Neurophysiol. Clin. Neurophysiol. 32, 54–71. 10.1016/S0987-7053(01)00289-1 - DOI - PubMed
    1. Feurra M., Pasqualetti P., Bianco G., Santarnecchi E., Rossi A., Rossi S. (2013). State-dependent effects of transcranial oscillatory currents on the motor system: what you think matters. J. Neurosci. 33, 17483–17489. 10.1523/JNEUROSCI.1414-13.2013 - DOI - PMC - PubMed
    1. Fröhlich F. (2015). Experiments and models of cortical oscillations as a target for noninvasive brain stimulation. Prog. Brain Res. 222, 41–73. 10.1016/bs.pbr.2015.07.025 - DOI - PubMed
    1. Fröhlich F., McCormick D. A. (2010). Endogenous electric fields may guide neocortical network activity. Neuron 67, 129–143. 10.1016/j.neuron.2010.06.005 - DOI - PMC - PubMed

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