BOLD Responses in Multisensory Spatial Cueing
Single Paper Presentation

Petra A. Arndt
Department of Psychology, Carl-von-Ossietzky University, Oldenburg, Germany

Simon Müller
Institute of Physics, Carl-von-Ossietzky University, Oldenburg, Germany

Mark W. Greenlee
Department of Psychology, Regensburg University, Regensburg

     Abstract ID Number: 153
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/18/2006 5:30 PM in Hamilton Building, McNeil Theatre
     (View Schedule)

Abstract
Recent studies showed that sensory-specific brain areas are involved in representing multimodal stimuli sharing semantic or other features. In this fMRI-study we investigate whether this holds for multisensory spatial cueing. In a forced-choice paradigm subjects indicated the position of a previously learned object (gabor stimulus with specific orientation) which is presented together with a distractor. A virtual-acoustics auditory cue given 200ms before visual stimulus onset is located at the target position in 80% and at the distractor position in 20% of the bimodal trials. Unimodal visual, unimodal auditory, bimodal trials and a baseline condition were presented in pseudorandom order. Using sparse imaging technique BOLD-signals were acquired in visual and auditory cortices, parts of the parietal and of the frontal lobe. A random effects analysis (12 participants) revealed activity in the visual cortex under auditory stimulation. This may mirror visual-auditory interaction or the fact that participants expect the target at a specific position. A strong, lateralized activation of the auditory cortex under unimodal visual stimulation suggests an involvement of sensory-specific areas in multisensory cueing. Moreover the contrasts of bimodal vs. visual stimulation and of valid vs. invalid cued trials show activation in the occipito-parietal region involved in multisensory and attentional processes.