Neuromodulation of multisensory perception: A tDCS study of the sound-induced flash illusion

Nadia Bolognini, Angela Rossetti, Carlotta Casati, Flavia Mancini, Giuseppe Vallar

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)231-237
Number of pages7
Issue number2
Publication statusPublished - Jan 2011


  • Auditory
  • Multisensory processing
  • Neuromodulation
  • Perceptual illusion
  • Transcranial direct current stimulation
  • Visual

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Cognitive Neuroscience
  • Experimental and Cognitive Psychology


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