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Abstract:
Abstract: Visuo-tactile links have been demonstrated using
single cell recording in monkeys and behavioural procedures in
humans. Using event-related fMRI we investigated the possibility
that spatially congruent visuo-tactile stimulation may modulate
brain responses to peripheral visual stimuli. Six right-handed
volunteers were tested using a 2x2 factorial design. One factor was
the side of the visual stimulation (left or right). The second
factor was the presence of tactile stimulation on the right index
finger (present or absent). The right visual stimulation was
delivered near to the right index finger. The task was to quickly
respond to every visual stimulus. The first step of the analysis
was to identify brain areas showing a main effect of side of the
visual stimulation. These were found in the contralateral
extrastriate cortex. Within these areas, we then tested for an
interaction between side and presence of the tactile stimulation.
The left lingual gyrus showed significant modulation. The effect of
side of the visual stimulation was increased in the context of the
contralateral tactile stimulation. Maximal response was observed
when both visual and tactile events occurred simultaneously in the
right hemifield. We conclude that spatial congruence of cross-modal
stimulations may influence activity in brain areas usually
considered unimodal.
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