Keeping in Touch with One’s Self: Multisensory Mechanisms of Self-Consciousness

Document Type: 
Article
Article Type: 
Experimental
Disciplines: 
Neuroscience
Topics: 
Sensory Systems
Keywords: 
bodily self, tactile, visual, multisensory, crossmodal congruency effect, full body illusion
Deposited by: 
Jane Aspell
Contact email: 
jane.aspell@epfl.ch
Date of Issue: 
2009
Authors: 
Jane E. Aspell, Bigna Lenggenhager, Olaf Blanke
Journal/Publication Title: 
PLoS ONE
Volume: 
4
Issue Number: 
8
Page Range: 
e6488.
Number of Pages: 
10
Publisher: 
Public Library of Science
Official URL: 
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006488
Alternative URL: 
doi:10.1371/journal.pone.0006488
Publish status: 
Published
Abstract: 
Background The spatial unity between self and body can be disrupted by employing conflicting visual-somatosensory bodily input, thereby bringing neurological observations on bodily self-consciousness under scientific scrutiny. Here we designed a novel paradigm linking the study of bodily self-consciousness to the spatial representation of visuo-tactile stimuli by measuring crossmodal congruency effects (CCEs) for the full body. Methodology/Principal Findings We measured full body CCEs by attaching four vibrator-light pairs to the trunks (backs) of subjects who viewed their bodies from behind via a camera and a head mounted display (HMD). Subjects made speeded elevation (up/down) judgments of the tactile stimuli while ignoring light stimuli. To modulate self-identification for the seen body subjects were stroked on their backs with a stick and the felt stroking was either synchronous or asynchronous with the stroking that could be seen via the HMD. We found that (1) tactile stimuli were mislocalized towards the seen body (2) CCEs were modulated systematically during visual-somatosensory conflict when subjects viewed their body but not when they viewed a body-sized object, i.e. CCEs were larger during synchronous than during asynchronous stroking of the body and (3) these changes in the mapping of tactile stimuli were induced in the same experimental condition in which predictable changes in bodily self-consciousness occurred. Conclusions/Significance These data reveal that systematic alterations in the mapping of tactile stimuli occur in a full body illusion and thus establish CCE magnitude as an online performance proxy for subjective changes in global bodily self-consciousness.
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