Article

This study explores whether brain polarization could be effective in modulating
multisensory audiovisual interactions in the human brain, as measured by the
'sound-induced flash illusion' (Shams et al., 2000). In different sessions,
healthy participants performed the task while receiving anodal, cathodal, or sham
tDCS (2 mA, 8 min) to the occipital, temporal, or posterior parietal cortices. We
found that up- or down-regulating cortical excitability by tDCS can facilitate or
reduce audiovisual illusions, depending on the current polarity, the targeted
area, and the illusory percept. Specifically, the perceptual 'fission' of a
single flash, due to multiple beeps, was increased after anodal tDCS of the
temporal cortex, and decreased after anodal stimulation of the occipital cortex.
A reversal of such effects was induced by cathodal tDCS. Conversely, the
perceptual 'fusion' of multiple flashes due to a single beep was unaffected by
tDCS. This evidence adds novel clues on the cortical substrate of the generation
of the sound-flash illusion, and opens new attractive possibilities for
modulating multisensory perception in humans: tDCS appears to be an effective
tool to modulate the conscious visual experience associated with multisensory
interactions, by noninvasively shifting cortical excitability within occipital or
temporal areas.
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Langue : ANGLAIS