EEG-theta associated with audio-visual binding
Poster Presentation

Matthias Bischoff
Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany

Gebhard Sammer
Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany

Carlo Blecker
Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany

Bertram Walter
Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany

Dieter Vaitl
Bender Institute of Neuroimaging, Justus-Liebig-University Giessen, Germany

     Abstract ID Number: 137
     Full text: Not available
     Last modified: March 18, 2006
     Presentation date: 06/19/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
Audio-visual binding - as subset of crossmodal integration - describes the combination of information across both these senses to the subjective unified perception of a bound object.
Brain-physiological correlates of audio-visual binding are investigated by using a bias-effect of crossmodal integration, the “ventriloquism-effect”(VE). VE indicates the mislocation of an auditory stimulus towards a simultaneous visual stimulus. Two synchronous stimuli (disc and beep) alternating with a single visual stimulus were presented in the experimental condition, the occurence of VE (localization bias towards disc) indicates binding. Asynchronously presented stimuli (no localization bias) formed the control (no-binding) condition.
EEG was recorded during task performance (n = 19 subjects) in order to investigate effects of the binding process in the theta and alpha range. Theta has been proposed to play an associate-cognitive role, while alpha components respond to differences between adequate/inadequate stimulation (Demiralp & Basar, 1992).
Comparing trials of the experimental condition, in which a ventriloquism-effect was reported, with trials without localization bias in the no-binding condition different theta responses were found in frontal, central and parietal electrodes. We consider these theta responses to be related to the consciousness-related audio-visual binding.