The phase of pre-stimulus theta oscillations gates cortical information flow and predicts perception performance G Volberg1, S Hanslymayr2, M Wimber3, S S Dalal2, M W Greenlee1 |
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1Institute for Experimental Psychology, University of Regensburg, Germany |
| Contrary to the subjective impression that visual information flows continuously from our sensory channels, recent evidence suggests that the sensitivity for visual stimuli fluctuates periodically. The neural mechanisms underlying this perceptual sampling are yet unknown. We here tested the hypothesis that the perceptual sampling rhythm is mediated by on-going brain oscillations which gate the transfer and integration of information between higher and lower level visual processing regions. Human participants performed a contour detection task while brain activity was recorded simultaneously with EEG and fMRI. The results obtained from EEG-informed fMRI analysis and dynamic causal modelling demonstrate that the phase of an on-going 7 Hz oscillation prior to stimulus onset modulates perceptual performance and the bidirectional flow of information between the medial occipital cortex (putative V4) and right intraparietal sulcus. These findings suggest that brain oscillations gate visual perception by providing transient time windows for long-distance cortical information transfer. |
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