Prestimulus Oscillatory Brain Activity Influences The Perception Of The McGurk-Effect
-
1
University of Konstanz, Germany
-
2
University of Bangor, United Kingdom
The McGurk-effect is a perceptual illusion, which demonstrates an interaction between auditory and visual sensory systems in speech perception. If a mismatch between the perception of a sound and the accompanying visual input occurs, it has been observed that the unified perception of both modalities fuses to a novel percept that neither matches the sound nor the sight. This effect does not appear in all mismatched trials, but only in 60-80%. The present study was designed to clarify the conditions under which this effect occurs and to identify cerebral sources associated with it. We are interested in the potential influence of ongoing brain oscillations associated to and prior to varying perception. In the present study, videos of an actor articulating syllables (e.g. aba) were dubbed with the audio tracks of different syllables (e.g. aga). The subjects were presented with a sequence of 390 videos, part of which contained the original audio tracks, part of which contained mismatching tracks. As an indicator of the perception, the subjects had to report via button press what syllable they had perceived. MEG was used to record event related and oscillatory activity during the stimulation. Cortical sources associated with different perceptions were identified and phase-locking between these areas was analyzed. Previous studies have shown an increase in gamma band activity related to incongruent stimuli. FMRI-studies have shown an involvement of superior temporal gyrus in speech perception. Preliminary results indicate, that the perception of the McGurk-Effect is associated with both, a higher pre-stimulus gamma activity in parietal and frontal cortical areas and a higher post-stimulus gamma activity in parietal cortical areas. Differences in phase-locking of cortical sources between different perceptions were observed. We conclude, that certain ongoing brain oscillations facilitate the perception the McGurk-Effect and also influence the perception of natural stimuli.
Conference:
Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010.
Presentation Type:
Poster Presentation
Topic:
Sensory Processing and Functional Connectivity
Citation:
Keil
J,
Ihssen
N and
Weisz
N
(2010). Prestimulus Oscillatory Brain Activity Influences The Perception Of The McGurk-Effect.
Front. Neurosci.
Conference Abstract:
Biomag 2010 - 17th International Conference on Biomagnetism .
doi: 10.3389/conf.fnins.2010.06.00171
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
26 Mar 2010;
Published Online:
26 Mar 2010.
*
Correspondence:
Julian Keil, University of Konstanz, Konstanz, Germany, julian.keil@uni-konstanz.de