Neural correlates of the ventriloquist-illusion
Poster Presentation

Bjoern Bonath
Department of Neurology II Otto-von-Guericke-University Magdeburg

Toemme Noesselt
Department of Neurology II Otto-von-Guericke-University Magdeburg

Antigona Martinez
Department of Neurosciences University of California San Diego

Jyoti Mishra
Department of Neurosciences University of California San Diego

Kati Schwiecker
Department of Neurology II Otto-von-Guericke-University Magdeburg

Hans-Jochen Heinze
Department of Neurology II Otto-von-Guericke-University Magdeburg

Steven A. Hillyard
Department of Neurosciences University of California San Diego

     Abstract ID Number: 43
     Full text: Not available
     Last modified: May 31, 2007
     Presentation date: 07/06/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
When auditory and visual events are presented from different locations, the perceived sound source location is shifted towards the location of the visual stimulus (Ventriloquist Effect). We used scalp-recorded event related potentials (ERPs) and functional magnetic resonance imaging (fMRI) to identify the time-course and spatial distribution of the neural events that underlie this illusionary perception. In the present design, sounds were presented from loudspeakers at different spatial positions, with and without simultaneous flashes from LEDs at disparate locations. Subjects maintained fixation and performed a sound localization task after being explicitly instructed to ignore the visual stimuli. In accordance with previous studies, our behavioral results indicated a shift in the perceived sound position when sounds were presented together with a spatially disparate visual stimulus. In particular, the perceived sound position shifted towards the flash position. Congruent with this behavioral effect, we observed a modulation of the blood oxygenation level dependent (BOLD)-response in both visual and auditory cortical areas. Moreover, using ERPs the temporal dynamics of this effect could be established.