Semantic factors influence multisensory pairing: a transcranial magnetic stimulation study.
It is traditionally assumed that temporal and spatial factors determine whether information provided by different sensory modalities is combined in a single percept. However, neuropsychological reports of selective damage to audio-visual integration and recent neurophysiological results suggest that semantic factors related to the content of the stimuli could also play a role. As a means of extending evidence provided by neuropsychological dissociations we set up a direct comparison of two kinds of audio-visual pairs with different semantic properties and used transcranial magnetic stimulation (TMS). We investigated the selective impact of TMS on two kinds of audio-visual pairings presented under identical spatio-temporal conditions (face-voice and tone-shape pairings). Our results show that TMS applied over the left posterior parietal cortex at 200 ms disrupted audio-visual integration for the tone-shape pairings but not for the face-voice ones. Our data are consistent with neuropsychological findings and indicate that besides the well-known dimensions of spatial and temporal contiguity, content is an important determinant of audio-visual integration. Our study also illustrates the usefulness of TMS for addressing the role of semantic factors in multi-sensory perception
Pourtois
Gilles
G
Laboratory for Cognitive and Affective Neuroscience, Tilburg University, Warandelaan 2, PO Box 90153, 5000 LE Tilburg, The Netherlands.
de Gelder
Beatrice
B
D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D004558:Electric Stimulation; D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D012660:Semantics; D050781:Transcranial Magnetic Stimulation