Article

Bodily illusions modulate tactile perception

de Vignemont, F. and Ehrsson, H.H. and Haggard, P. (2005) Bodily illusions modulate tactile perception. Current Biology, 15 (14). pp.1286 - 1290. ISSN 09609822 DOI:3060
Source: OAI

ABSTRACT Touch differs from other exteroceptive senses in that the body itself forms part of the tactile percept. Interactions between proprioception and touch provide a powerful way to investigate the implicit body representation underlying touch. Here, we demonstrate that an intrinsic primary quality of a tactile object, for example its size, is directly affected by the perceived size of the body part touching it. We elicited proprioceptive illusions that the left index finger was either elongating or shrinking by vibrating the biceps or triceps tendon of the right arm while subjects grasped the tip of their left index finger. Subjects estimated the distance between two simultaneous tactile contacts on the left finger during tendon vibration. We found that tactile distances feel bigger when the touched body part feels elongated. Control tests showed that the modulation of touch was linked to the perceived index-finger size induced by tendon vibration. Vibrations that did not produce proprioceptive illusion had no effect on touch. Our results show that the perception of tactile objects is referenced to an implicit body representation and that proprioception contributes to this body representation. We also provide, for the first time, a quantitative, implicit measure of distortions of body size.

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Keywords

bigger
 
body part
 
body representation
 
body size
 
Control tests
 
exteroceptive senses
 
implicit body representation
 
implicit measure
 
intrinsic primary quality
 
left finger
 
left index finger
 
perceived index-finger size induced
 
proprioception contributes
 
proprioceptive illusion
 
tactile distances
 
tactile percept
 
tendon vibration
 
touched body part
 
triceps tendon
 
vibrating
 

F. de Vignemont