Selective Modulation of Interhemispheric Functional Connectivity by HD-tACS Shapes Perception

Oscillatory neuronal synchronization between cortical areas has been suggested to constitute a flexible mechanism to coordinate information flow in the human cerebral cortex. However, it remains unclear whether synchronized neuronal activity merely represents an epiphenomenon or whether it is causal...

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Bibliographic Details
Published in:PLoS biology Vol. 12; no. 12; p. e1002031
Main Authors: Helfrich, Randolph F., Knepper, Hannah, Nolte, Guido, Strüber, Daniel, Rach, Stefan, Herrmann, Christoph S., Schneider, Till R., Engel, Andreas K.
Format: Journal Article
Language:English
Published: United States Public Library of Science 01.12.2014
Public Library of Science (PLoS)
Subjects:
Adult
Behavior
Biology and Life Sciences
Cerebral cortex
Cerebrum - physiology
Cognition & reasoning
Computer and Information Sciences
Cortical Synchronization
Electric stimulation
Electrodes
Electroencephalography
Female
Gamma Rhythm - physiology
Health aspects
Humans
Male
Medicine and Health Sciences
Motion Perception - physiology
Nerve Net - physiology
Neural circuitry
Neurological research
Physiological aspects
Stroboscopy
Studies
Transcranial Direct Current Stimulation
Variance analysis
ISSN:1545-7885, 1544-9173, 1545-7885
Online Access:Get full text
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Summary:Oscillatory neuronal synchronization between cortical areas has been suggested to constitute a flexible mechanism to coordinate information flow in the human cerebral cortex. However, it remains unclear whether synchronized neuronal activity merely represents an epiphenomenon or whether it is causally involved in the selective gating of information. Here, we combined bilateral high-density transcranial alternating current stimulation (HD-tACS) at 40 Hz with simultaneous electroencephalographic (EEG) recordings to study immediate electrophysiological effects during the selective entrainment of oscillatory gamma-band signatures. We found that interhemispheric functional connectivity was modulated in a predictable, phase-specific way: In-phase stimulation enhanced synchronization, anti-phase stimulation impaired functional coupling. Perceptual correlates of these connectivity changes were found in an ambiguous motion task, which strongly support the functional relevance of long-range neuronal coupling. Additionally, our results revealed a decrease in oscillatory alpha power in response to the entrainment of gamma band signatures. This finding provides causal evidence for the antagonistic role of alpha and gamma oscillations in the parieto-occipital cortex and confirms that the observed gamma band modulations were physiological in nature. Our results demonstrate that synchronized cortical network activity across several spatiotemporal scales is essential for conscious perception and cognition.
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The authors have declared that no competing interests exist.
The author(s) have made the following declarations about their contributions: Conceived and designed the experiments: RFH HK DS SR CSH TRS AKE. Performed the experiments: RFH HK. Analyzed the data: RFH HK. Contributed reagents/materials/analysis tools: GN TRS. Wrote the paper: RFH. Discussed the results; edited and approved the manuscript: RFH HK GN DS SR CSH TRS AKE.
ISSN:1545-7885
1544-9173
1545-7885
DOI:10.1371/journal.pbio.1002031