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On the Role of Prestimulus Alpha Rhythms over Occipito-Parietal Areas in Visual Input Regulation: Correlation or Causation?

Romei, V and Gross, J and Thut, G (2010) 'On the Role of Prestimulus Alpha Rhythms over Occipito-Parietal Areas in Visual Input Regulation: Correlation or Causation?' Journal of Neuroscience, 30 (25). pp. 8692-8697. ISSN 0270-6474


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The posterior alpha rhythm (8-14 Hz), originating in occipito-parietal areas through thalamocortical generation, displays characteristics of visual activity in anticipation of visual events. Posterior alpha power is influenced by visual spatial attention via top-down control from higher order attention areas such as the frontal eye field. It covaries with visual cortex excitability, as tested through transcranial magnetic stimulation (TMS), and predicts the perceptual fate of a forthcoming visual stimulus. Yet, it is still unknown whether the nature of the relationship between this prestimulus alpha oscillation and upcoming perception is causal or only correlative. Here, wetested in the human brain whether the oscillation in the alpha band is causally shaping perception through directly stimulating visual areas via short trains of rhythmic TMS. We compared stimulation at alpha frequency (10 Hz) with two control frequencies in the theta (5 Hz) and beta bands (20 Hz), and assessed immediate perceptual outcomes. Target visibility was significantly modulated by alpha stimulation, relative to both control conditions. Alpha stimulation selectively impaired visual detection in the visual field opposite to the stimulated hemisphere, while enhancing detection ipsilaterally. These frequency-specific effects were observed both for stimulation over occipital and parietal areas of the left and right hemispheres and were short lived: they were observed by the end of the TMS train but were absent 3 s later. This shows that the posterior alpha rhythm is actively involved in shaping forthcoming perception and, hence, constitutes a substrate rather than a mere correlate of visual input regulation. Copyright © 2010 the authors.

Item Type: Article
Uncontrolled Keywords: Occipital Lobe; Parietal Lobe; Visual Pathways; Humans; Alpha Rhythm; Brain Mapping; Analysis of Variance; Photic Stimulation; Visual Perception; Attention; Image Processing, Computer-Assisted; Adult; Female; Male; Transcranial Magnetic Stimulation; Functional Laterality
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Divisions: Faculty of Science and Health
Faculty of Science and Health > Psychology, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 06 Mar 2013 14:27
Last Modified: 15 Jan 2022 00:31

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