Title
The sound of size: Crossmodal binding in pitch-size synesthesia: A combined TMS, EEG and psychophysics study.
Abstract
Crossmodal binding usually relies on bottom-up stimulus characteristics such as spatial and temporal correspondence. However, in case of ambiguity the brain has to decide whether to combine or segregate sensory inputs. We hypothesise that widespread, subtle forms of synesthesia provide crossmodal mapping patterns which underlie and influence multisensory perception. Our aim was to investigate if such a mechanism plays a role in the case of pitch-size stimulus combinations. Using a combination of psychophysics and ERPs, we could show that despite violations of spatial correspondence, the brain specifically integrates certain stimulus combinations which are congruent with respect to our hypothesis of pitch-size synesthesia, thereby impairing performance on an auditory spatial localisation task (Ventriloquist effect). Subsequently, we perturbed this process by functionally disrupting a brain area known for its role in multisensory processes, the right intraparietal sulcus, and observed how the Ventriloquist effect was abolished, thereby increasing behavioural performance. Correlating behavioural, TMS and ERP results, we could retrace the origin of the synesthestic pitch-size mappings to a right intraparietal involvement around 250ms. The results of this combined psychophysics, TMS and ERP study provide evidence for shifting the current viewpoint on synesthesia more towards synesthesia being at the extremity of a spectrum of normal, adaptive perceptual processes, entailing close interplay between the different sensory systems. Our results support this spectrum view of synesthesia by demonstrating that its neural basis crucially depends on normal multisensory processes.
Year
DOI
Venue
2012
10.1016/j.neuroimage.2011.06.095
NeuroImage
Keywords
Field
DocType
Crossmodal,Synesthesia spectrum,Parietal cortex,TMS,ERP
Crossmodal,Developmental psychology,Synesthesia,Grapheme-color synesthesia,Multisensory integration,Cognitive psychology,Psychology,Stimulus (physiology),Sensory system,Psychophysics,Perception
Journal
Volume
Issue
ISSN
59
1
1053-8119
Citations 
PageRank 
References 
6
0.78
3
Authors
4
Name
Order
Citations
PageRank
Nina Bien182.25
Sanne ten Oever2102.97
rainer goebel347640.13
Alexander T Sack4163.25