Searching the Resource Information Network
Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.
The successful integration of visual and auditory stimuli requires information about whether visual and auditory signals originate from corresponding places in the external world. Here we report crossmodal effects of spatially congruent and incongruent audio-visual (AV) stimulation. Visual and auditory stimuli were presented from one of four horizontal locations in external space. Seven healthy human subjects had to assess the spatial fit of a visual stimulus (i.e. a gray-scaled picture of a cartoon dog) and a simultaneously presented auditory stimulus (i.e. a barking sound). Functional magnetic resonance imaging (fMRI) revealed two distinct networks of cortical regions that processed preferentially either spatially congruent or spatially incongruent AV stimuli. Whereas earlier visual areas responded preferentially to incongruent AV stimulation, higher visual areas of the temporal and parietal cortex (left inferior temporal gyrus [ITG], right posterior superior temporal gyrus/sulcus [pSTG/STS], left intra-parietal sulcus [IPS]) and frontal regions (left pre-central gyrus [PreCG], left dorsolateral pre-frontal cortex [DLPFC]) responded preferentially to congruent AV stimulation. A position-resolved analysis revealed three robust cortical representations for each of the four visual stimulus locations in retinotopic visual regions corresponding to the representation of the horizontal meridian in area V1 and at the dorsal and ventral borders between areas V2 and V3. While these regions of interest (ROIs) did not show any significant effect of spatial congruency, we found subregions within ROIs in the right hemisphere that showed an incongruency effect (i.e. an increased fMRI signal during spatially incongruent compared to congruent AV stimulation). We interpret this finding as a correlate of spatially distributed recurrent feedback during mismatch processing: whenever a spatial mismatch is detected in multisensory regions (such as the IPS), processing resources are re-directed to low-level visual areas.
Pubmed ID: 16797610
Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.
Brain Innovation B.V. is developing scientific software in the field of human and animal brain imaging, neural network simulation and computer-based experimental control. Our current major product, BrainVoyager QX, is a commercially available cross-platform neuroimaging tool, which is used in hundreds of labs across the planet. Turbo-BrainVoyager is an easy to use program for real-time data analysis, which allows to observe a subject''s or patient''s brain activity during an ongoing functional MRI scanning session. TMS Neuronavigator provides the hard- and software to navigate a TMS coil to desired anatomical or functionally defined brain regions. We also provide free software products. BrainVoyager Brain Tutor allows to learn about brain areas by clicking on rotatable 3D brain models. StimulDX is a powerful stimulation software based on Microsofts DirectX API, which we will make available for free download in the near future.
View all literature mentions