Frontiers Media, Frontiers in Human Neuroscience, (8), 2014
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Background: Studies in animals and humans indicate that the interruption of the body-brain connections following spinal cord injury (SCI) leads to plastic cerebral reorganization. Objective: To explore whether inducing the Rubber Hand Illusion (RHI) via synchronous multisensory visuo-tactile bodily stimulation may revealdisclose the perceptual correlates of plastic remapping in SCI. Methods: 16 paraplegic (P), 16 tetraplegic (T) and 16 healthy (H) participants were tested in a novel environmentparadigm in order to for exploreing whether RHI iswas induced by touches, involving not only on the participants' left hand but also on the left hemi-face. Touchinges on the participant’s actualreal hand or face was eithercould be synchronous or asynchronous with the stimuli which involved a fakeseen on the rubber hand. We assessed two components of the illusion, namely perceived changes in theof real hand in space (indexed by proprioceptive drift) and ownership of the rubber hand (indexed by subjective responses to an ad-hoc developed questionnaire). Results: Proprioceptive drift and ownership were found in the H group only in the condition where touchinges were was synchronously done todelivered on the left real and fake hand. InBy contrast, no drift was found in the SCI patients who however showed ownership after both synchronous and asynchronous hand stroking. Importantly, only T also showed the effect also after synchronous face stroking. Conclusions: RHI may revealdisclose plastic phenomena in SCI. In hand representation- deprived T participants, stimuli on the face (represented contiguously in the somatic and motor systems), drive the sense of hand ownership. This hand-face remapping phenomenon may be useful in terms offor restoring athe sense of self in massively deprived individuals.