Neural correlates of synchrony perception using audiovisual speech stimuli
Poster Presentation

Daniel Bergmann
Department of Neurology II, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany

Charles Spence
Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD, United Kingdom

Hans-Jochen Heinze
Department of Neurology II, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany

Toemme Noesselt
Department of Neurology II, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany

     Abstract ID Number: 145
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/18/2006 4:00 PM in Hamilton Building, Foyer
     (View Schedule)

Abstract
We explored the neural bases of the perception of synchrony for complex audiovisual speech stimuli using short video-clips. Subjects’ (n=12) individual delay-thresholds were determined and then used in a subsequent fMRI-experiment. Auditory, visual, and polysensory brain-areas were identified in preliminary localizer runs before the main experimental session in which three conditions (sound preceding vision, synchronous, vision preceding sound) were presented while subjects indicated whether they perceived the video-clips as being synchronous or not. Analysis of the fMRI data compared the sensory conditions, the subjects’ responses and perception within auditory, visual and polysensory brain areas. Preliminary results reveal two distinct cortical networks for the perception of synchrony vs. asynchrony: In particular, synchrony perception was associated with the modulation of activation in the fusiform gyrus, the STS, and the Planum temporale/Insula within the right hemisphere; By contrast, activations specifically associated with the perception of asynchrony were seen in the fusiform gyrus, the IPS and the IFG/MFG bilaterally. Analysis of the sensory conditions and the subjects’ decisions revealed modulations of early visual, auditory and multisensory areas. Taken together, these results suggest that perception of audiovisual synchrony and asynchrony might be mediated by two different albeit overlapping neural systems.