title: The wheelchair as a full-body tool extending the peripersonal space.
abstract: Dedicated multisensory mechanisms in the brain represent peripersonal space (PPS), a limited portion of space immediately surrounding the body. Previous studies have illustrated the malleability of PPS representation through hand-object interaction, showing that tool use extends the limits of the hand-centered PPS. In the present study we investigated the effects of a special tool, the wheelchair, in extending the action possibilities of the whole body. We used a behavioral measure to quantify the extension of the PPS around the body before and after Active (Experiment 1) and Passive (Experiment 2) training with a wheelchair and when participants were blindfolded (Experiment 3). Results suggest that a wheelchair-mediated passive exploration of far space extended PPS representation. This effect was specifically related to the possibility of receiving information from the environment through vision, since no extension effect was found when participants were blindfolded. Surprisingly, the active motor training did not induce any modification in PPS representation, probably because the wheelchair maneuver was demanding for non-expert users and thus they may have prioritized processing of information from close to the wheelchair rather than at far spatial locations. Our results suggest that plasticity in PPS representation after tool use seems not to strictly depend on active use of the tool itself, but is triggered by simultaneous processing of information from the body and the space where the body acts in the environment, which is more extended in the case of wheelchair use. These results contribute to our understanding of the mechanisms underlying body-environment interaction for developing and improving applications of assistive technological devices in different clinical populations.
authors.affiliation: Istituto di Ricovero e Cura a Carattere Scientifico, Santa Lucia Foundation Rome, Italy ; Laboratory of Cognitive Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Giulia
authors.initials: G
authors.lastname: Galli
authors.affiliation: Laboratory of Cognitive Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Center for Neuroprosthetics, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Vanderbilt Brain Institute, Vanderbilt University Nashville, TN, USA.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Noel
authors.affiliation: Laboratory of Cognitive Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Center for Neuroprosthetics, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Canzoneri
authors.affiliation: Laboratory of Cognitive Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Center for Neuroprosthetics, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Department of Neurology, University Hospital Geneva Geneva, Switzerland.
authors.forename: Olaf
authors.initials: O
authors.lastname: Blanke
authors.affiliation: Laboratory of Cognitive Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Center for Neuroprosthetics, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Serino
keywords: assistive device; embodiment; peripersonal space; tool use; visual spatial exploration