Gamma flicker triggers attentional selection without awareness
- aDepartment of Psychology, Leopoldstrasse 13, Ludwig Maximilian University, 80802 Munich, Germany;
- bSchool of Psychology, Malet Street, Birkbeck, University of London, WC1E 7HX London, United Kingdom;
- cCentre for Cognition and Neuroimaging, Brunel University, Uxbridge, UB8 3PH Middlesex, United Kingdom; and
- dDepartment of Psychology, Tel Aviv University, Ramat Aviv 69978, Israel
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Edited by James L. McClelland, Stanford University, Stanford, CA, and approved December 2, 2008
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↵1F.B. and S.W.C. contributed equally to this work. (received for review October 21, 2008)
Abstract
Gamma band modulations in neural activity have been proposed to mediate attentional processes. To support a causal link between gamma activity and attentional selection, we attempt to evoke gamma oscillations by a 50-Hz subliminal flicker. We find that a subliminal 50-Hz flicker at a target location, before target presentation, speeds up and enhances target detection and discrimination. This effect is specific to the middle of the gamma range because it is not evident at <35-Hz flicker. It requires 300 ms to build up, dissipates within 250 ms of flicker offset, and shows a tendency to invert after 500 ms. The results are discussed in relation to a role for gamma band neural synchrony in the allocation of visual attention.
Footnotes
- 2To whom correspondence should be addressed. E-mail: s.cheadle{at}bbk.ac.uk
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Author contributions: F.B., S.W.C., A.P., H.J.M., and M.U. designed research; F.B., S.W.C., and M.U. performed research; F.B., S.W.C., and M.U. analyzed data; and F.B., S.W.C., A.P., H.J.M., and M.U. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0810496106/DCSupplemental.
- © 2009 by The National Academy of Sciences of the USA
