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Phase-specific manipulation of rhythmic brain activity by transcranial alternating current stimulation
Marina Fiene1, Bettina C Schwab1, Jonas Misselhorn1
1Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany.
Brain Stimulation
|June 14, 2020
Summary
Transcranial alternating current stimulation (tACS) can modulate brain activity in a phase-specific manner in humans. Optimal tACS timing depends on neural response timing, suggesting targeted neuromodulation potential.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Neuroimaging
Background:
- Oscillatory phase is crucial for neural activity spatiotemporal structure.
- Transcranial alternating current stimulation (tACS) offers a promising method for modulating brain rhythms.
- The phase-specificity of tACS effects in humans remains under investigation.
Purpose of the Study:
- Investigate the phase-specificity of tACS on visually evoked steady-state responses (SSRs).
- Determine the influence of tACS on SSR amplitude in healthy human participants.
- Validate experimental findings using a neural network model.
Main Methods:
- Utilized an intermittent electrical stimulation protocol.
- Assessed tACS influence on SSR amplitude post-stimulation.
- Employed a neural network model for validation.
Main Results:
- Observed SSR amplitude modulation dependent on flicker-tACS phase shift.
- Found tACS effect size negatively correlated with flicker-evoked activity strength.
- Localized neural sources of phase-specific effects in the parieto-occipital cortex.
Conclusions:
- Provided electrophysiological evidence for phase-specific tACS modulations in humans.
- Demonstrated that optimal tACS timing correlates with cortical SSR phase delays.
- Highlighted tACS potential for controlled, phase-specific neural activity modulation.
