Processing of visuo-tactile spatial congruency does not depend on available visuo-spatial and memory resources
Single Paper Presentation

Ulrike Zimmer
NeuroImaging Laboratory - Fondazione Santa Lucia

Emiliano Macaluso
NeuroImaging Laboratory - Fondazione Santa Lucia

     Abstract ID Number: 28
     Full text: Not available
     Last modified: March 3, 2006
     Presentation date: 06/18/2006 5:30 PM in Hamilton Building, McNeil Theatre
     (View Schedule)

Abstract
Tactile stimuli presented at the same location as a visual target can yield to increased activity in contralateral occipital cortex, compared with spatially-incongruent bimodal stimulation. Does this crossmodal congruency effect in visual cortex depend on available cognitive resources? Visual attention and visual working memory can modulate activation associated with visual distractor-stimuli in visual cortex, reducing brain responses during high attentional load or low memory load. Here, we asked if visual cognitive load also affects multisensory processing in visual cortex. In two separate fMRI studies we manipulated the load-level of a non-spatial working memory task, and of an endogenous visuo-spatial attention task. Concurrently with the primary task, we presented visual and tactile stimuli that were either spatially-congruent or spatially-incongruent. We assessed any enhancement of activity for congruent versus incongruent bimodal stimulation, as a function of visual load. In both experiments, we found crossmodal enhancements for spatially-congruent stimulation in contralateral occipital cortex. Critically, these crossmodal spatial effects were present irrespective of the level of load, both in the non-spatial working memory and in the visuo-spatial attention experiment. We conclude that processing of visuo-tactile spatial congruence in visual cortex does not depend on available visuo-spatial and memory resources.