Does visual experience shape body schema ?
Résumé
The representation of touch on our body is not veridical. For instance, tactile distances across the limb (mediolateral) are always perceived as larger than those running along the limb (proximodistal). This tactile anisotropy reflects distortions in body-shape representation, such that the arms are perceived wider than they are. It has been suggested that such an effect may arise because the primary somatosensory representation of touch is rescaled into an object-centered space according to the visual experience of the body. To causally test the role of visual experience on body map representation, we investigated tactile distance perception in sighted and early blind individuals comparing mediolateral and proximodistal tactile distances of stimuli presented on the ventral and dorsal part of their arm, wrist, and hand. Overestimation of distances in mediolateral over proximodistal body axes was found in both sighted and blind people. However, the magnitude of the anisotropy was significantly reduced in the arms of blind people. We conclude that tactile distance perception is mediated by similar mechanisms in both sighted and blind people; but that vision partly affects the transformation of somatosensory representations into an object-centered space.
Domaines
NeurosciencesOrigine | Fichiers produits par l'(les) auteur(s) |
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