Multi-modal versus modality-specific activation within the "what" and "where" processing streams for sounds and vibro-tactile stimuli
laurent albert renier, Irina Anurova, Anne ghislaine De Volder, Synnöve Carlson, John VanMeter, Josef Peter Rauschecker
Poster
Time: 2009-06-30 09:00 AM – 10:30 AM
Last modified: 2009-06-04
Abstract
The segregation between cortical pathways for the identification and localization of objects is thought of as a general organizational principle in the brain. Yet, little is known about the uni- versus multi-modal nature of these processing streams. The main purpose of the present study was to test whether the auditory and tactile dual pathways converged into specialized multisensory brain areas. We used fMRI to compare directly in the same subjects the brain activation related to localization and identification of comparable auditory and vibro-tactile stimuli. Results indicate that the right inferior frontal gyrus (IFG) and both left and right insula were more activated during identification conditions than during localization in both touch and audition. An inverse dissociation was found for the left and right inferior parietal lobules (IPL), the left superior parietal lobule (SPL) and the right precuneus-SPL, which were all more activated during localization conditions in the two modalities. We propose that specialized areas in the right IFG and the left and right insula are multisensory operators for the processing of stimulus identity while parts of the left and right IPL and SPL are specialized for the processing of spatial attributes independently of sensory modality.