Frequency‐dependent t<scp>ACS</scp> modulation of <scp>BOLD</scp> signal during rhythmic visual stimulation

Chai, Yuhui; Sheng, Jin; Bandettini, Peter A.; Gao, Jia‐Hong

doi:10.1002/hbm.23990

Cited by 18 publications

(14 citation statements)

References 33 publications

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“…These regions were part of the flicker-responsive areas as shown by the distribution of PLV during flicker stimulation without tACS. In a recent study by Chai et al (43), an increase in hemodynamic response to flicker stimulation by simultaneously started tACS at the flicker frequency or its first harmonic was localized primarily in bilateral cuneus and middle occipital gyrus. In line with our study, main stimulation effects were seen in regions that were driven by visual flicker and targeted by the tACS electric field, thus, providing evidence for a topographically specific modulation.…”

Section: Discussionmentioning

confidence: 90%

Phase-specific manipulation of neural oscillatory activity by transcranial alternating current stimulation

Fiene

Schwab

Misselhorn

et al. 2019

Preprint

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Oscillatory phase has been proposed as key parameter defining the spatiotemporal structure of neural activity. Phase alignment of oscillations by transcranial alternating current stimulation (tACS) may offer a unique opportunity to enhance our understanding of brain rhythms and to alter brain function. However, the precise mechanism and effectiveness of tACS are still critically debated. Here, we investigated the phase-specificity of tACS effects on visually evoked steady state responses (SSR) measured by electroencephalography (EEG). Using an intermittent electrical stimulation protocol, we assessed the influence of tACS on SSR amplitude as a function of phase shift between rhythmic sensory and electrical stimulation in the interval immediately following tACS. Visual flicker was delivered at six different phase angles relative to the tACS cycle. Participants were presented with flicker and high-definition tACS over the occipital cortex at 10 Hz in two sessions using active or sham stimulation. We observed that the phase shift between flicker and tACS modulates evoked SSR amplitudes. The amplitude change over phase shift conditions was significant for both general and sinusoidal modulation measures. Neural sources of phase-specific effects were localized in the parietooccipital cortex within flicker-aligned regions. Importantly, tACS effects were stronger in subjects with lower phase locking between EEG and flicker. Overall, our data provide evidence for phase alignment of brain activity by tACS, since the change in SSR amplitude can only result from phase-specific interactions with the applied electric fields. This finding corroborates the physiological efficacy of tACS and highlights its potential for controlled modulation of brain signals. Keywordstranscranial alternating current stimulation (tACS), EEG, phase, alpha oscillations, visual flicker Significance StatementThe lacking proof of phase-specific effects of transcranial alternating current stimulation (tACS) on neural activity in humans still restricts its potential to advance knowledge on the functional significance of brain oscillations. We show that the phase shift between concurrent 10 Hz tACS and precisely controlled oscillatory activity via visual flicker modulated the amplitude of evoked neural oscillations. Interindividual differences in tACS effect size were dependent on the current brain state. Our findings provide electrophysiological evidence for the capability of tACS to phase-align intrinsic neural activity. These mechanistic insights emphasize the value of tACS to advance research on the causal role of brain rhythms and offer important implications for the treatment of disturbed oscillatory patterns and cortical connectivity in brain disorders.

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Section: Discussionmentioning

confidence: 90%

Phase-specific manipulation of neural oscillatory activity by transcranial alternating current stimulation

Fiene

Schwab

Misselhorn

et al. 2019

Preprint

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“…Our Study contributes to the recently developing literature on concurrent use of tACS and periodic visual stimulation as a promising research technique in neuroscience (Ruhnau et al, 2016: Chai et al, 2018 and the importance of phase synchrony between them (Fiene et al, 2019) and demonstrate a behavioural effect for the first time. This will be of interest to researchers using electrical brain stimulation and sensory stimulation techniques.…”

Section: Discussionmentioning

confidence: 62%

Theta Phase-Dependent Modulation of Perception by Concurrent tACS and Periodic Visual Stimulation

Somer

Allen

Brooks

et al. 2019

Preprint

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Background: Sensory perception can be modulated by the phase of neural oscillations, especially in the theta and alpha ranges. Oscillatory activity in the visual cortex can be entrained by transcranial alternating current stimulation (tACS) as well as periodic visual stimulation (i.e., flicker). Combined tACS and visual flicker stimulation modulates bloodoxygen-level-dependent (BOLD) responses and concurrent 4 Hz auditory click-trains and tACS modulates auditory perception in a phase-dependent way.Objective: In the present study, we investigated if phase synchrony between concurrent tACS and periodic visual stimulation (i.e., flicker) can modulate performance on a visual matching task.Methods: Participants completed a visual matching task on a flickering visual stimulus while receiving either in-phase (0 degree) or asynchronous (180, 90, or 270 degrees) tACS at alpha or theta frequency. Stimulation was applied over either occipital cortex or dorsolateral prefrontal cortex (DLPFC).Results: Visual performance was significantly better during theta frequency tACS over the visual cortex when it was in-phase (0 degree) with visual stimulus flicker, compared to antiphase (180 degree). This effect did not appear with alpha frequency flicker or with DLPFC stimulation. Furthermore, a control sham group showed no effect. There were no significant performance differences amongst the asynchronous (180, 90, and 270 degrees) phase conditions.Conclusion: Extending previous studies on visual and auditory perception, our results support a crucial role of oscillatory phase in sensory perception and demonstrate a behaviourally relevant combination of visual flicker and tACS. The spatial and frequency specificity of our results have implications for research on the functional organisation of perception.

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“…Further, both sensory and transcranial stimulation techniques were shown to be effective in phasic modulation of perception through entrainment of neural oscillations by EEG or magnetoencephalography (MEG) recordings and behavioural measures (Henry & Obleser, 2012;Jaegle, & Ro, 2014;Neuling, Rach, Wagner, Wolters, & Herrmann, 2012;Spaak et al, 2014). Chai, Sheng, Bandettini, and Gao (2018) combined tACS with periodic visual stimulation.…”

Section: Introductionmentioning

confidence: 99%

“…We included DLPFC as a control location as it is associated with higher level cognitive processes such as short and long-term memory (e.g., Crowley, Bendor, & Javadi, 2019;Curtis & D'Esposito, 2003;Javadi, Glen, Halkiopoulos, Schulz, & Spiers, 2017;Javadi & Walsh, 2012) Therefore, it would not be likely to affect lower level perceptual performance. We also investigated if alpha stimulation (10 Hz) would affect task performance as this is another frequency range that has been repeatedly linked to visual perception (e.g., Babiloni, Vecchio, Bultrini, Luca Romani, & Rossini, 2005;Busch et al, 2009;Chai et al, 2018;Kanai et al, 2008;Mathewson et al, 2009;Spaak et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Theta Phase-dependent Modulation of Perception by Concurrent Transcranial Alternating Current Stimulation and Periodic Visual Stimulation

Somer

Allen

Brooks

et al. 2020

Journal of Cognitive Neuroscience

View full text Add to dashboard Cite

Sensory perception can be modulated by the phase of neural oscillations, especially in the theta and alpha ranges. Oscillatory activity in the visual cortex can be entrained by transcranial alternating current stimulation (tACS) as well as periodic visual stimulation (i.e., flicker). Combined tACS and visual flicker stimulation modulates BOLD response, and concurrent 4-Hz auditory click train, and tACS modulate auditory perception in a phase-dependent way. In this study, we investigated whether phase synchrony between concurrent tACS and periodic visual stimulation (i.e., flicker) can modulate performance on a visual matching task. Participants completed a visual matching task on a flickering visual stimulus while receiving either in-phase (0°) or asynchronous (180°, 90°, or 270°) tACS at alpha or theta frequency. Stimulation was applied over either occipital cortex or dorsolateral pFC. Visual performance was significantly better during theta frequency tACS over the visual cortex when it was in-phase (0°) with visual stimulus flicker, compared with antiphase (180°). This effect did not appear with alpha frequency flicker or with dorsolateral pFC stimulation. Furthermore, a control sham group showed no effect. There were no significant performance differences among the asynchronous (180°, 90°, and 270°) phase conditions. Extending previous studies on visual and auditory perception, our results support a crucial role of oscillatory phase in sensory perception and demonstrate a behaviorally relevant combination of visual flicker and tACS. The spatial and frequency specificity of our results have implications for research on the functional organization of perception.

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Frequency‐dependent tACS modulation of BOLD signal during rhythmic visual stimulation

Cited by 18 publications

References 33 publications

Phase-specific manipulation of neural oscillatory activity by transcranial alternating current stimulation

Phase-specific manipulation of neural oscillatory activity by transcranial alternating current stimulation

Theta Phase-Dependent Modulation of Perception by Concurrent tACS and Periodic Visual Stimulation

Theta Phase-dependent Modulation of Perception by Concurrent Transcranial Alternating Current Stimulation and Periodic Visual Stimulation

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