Crossmodal object binding increase perceived contrast
Poster Presentation

Sascha Tyll
Department of Neurology II, Otto von Guericke University Magdeburg, Germany

Martin Kanowski
Department of Neurology II, Otto von Guericke University Magdeburg, Germany

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

Toemme Noesselt
Department of Neurology II, Otto von Guericke University Magdeburg, Germany

     Abstract ID Number: 157
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/20/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
In the present study we varied the contrast of a visual stimulus (defined by 60% and 80% hit rate respectively) while subjects performed a visual detection task. In half of the trials a task-irrelevant sound was presented as well. We found an increase in detectability for the 60% visual stimuli if paired with an irrelevant auditory stimulus but not for the 80% visual stimulus. To determine the neural correlate of this effect event related fMRI was used (n=6). In addition to multimodal structures (superior temporal sulcus) early visual areas in both the dorsal (superior occipital gyrus) and ventral stream (fusiform gyrus) were modulated in congruence with the behavioural effect. Further, unimodal auditory areas as early as Heschl’s gyrus were modulated as well. The identified network of visual, auditory and multimodal areas indicates that the visual and auditory information - presented in both temporal and spatial proximity - is fused to form a multimodal object. This process of ‘multisensory object binding’ might generate a more salient representation of the unimodal object attributes as indicated by the increase of visual detectability.