title: Visual appearance of a virtual upper limb modulates the temperature of the real hand: a thermal imaging study in Immersive Virtual Reality.
abstract: To explore the link between Sense of Embodiment (SoE) over a virtual hand and physiological regulation of skin temperature, 24 healthy participants were immersed in virtual reality through a Head Mounted Display and had their real limb temperature recorded by means of a high-sensitivity infrared camera. Participants observed a virtual right upper limb (appearing either normally, or with the hand detached from the forearm) or limb-shaped non-corporeal control objects (continuous or discontinuous wooden blocks) from a first-person perspective. Subjective ratings of SoE were collected in each observation condition, as well as temperatures of the right and left hand, wrist and forearm. The observation of these complex, body and body-related virtual scenes resulted in increased real hand temperature when compared to a baseline condition in which a 3d virtual ball was presented. Crucially, observation of non-natural appearances of the virtual limb (discontinuous limb) and limb-shaped non-corporeal objects elicited high increase in real hand temperature and low SoE. In contrast, observation of the full virtual limb caused high SoE and low temperature changes in the real hand with respect to the other conditions. Interestingly, the temperature difference across the different conditions occurred according to a topographic rule that included both hands. Our study sheds new light on the role of an external hand's visual appearance and suggests a tight link between higher-order bodily self-representations and topographic regulation of skin temperature.
authors.affiliation: Fondazione Santa Lucia, IRCCS, Via Ardeatina 306, Rome, Italy.|SCNLab, Department of Psychology, University of Rome "La Sapienza", Via dei Marsi, 00185, Rome, Italy.
authors.forename: Gaetano
authors.identifier: 0000-0002-3037-0526
authors.initials: G
authors.lastname: Tieri
authors.affiliation: BrainTrends Ltd, Applied Neuroscience, Rome, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Gioia
authors.affiliation: NPsy-Lab.VR, Department of Human Sciences, University of Verona, Verona, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Scandola
authors.affiliation: BrainTrends Ltd, Applied Neuroscience, Rome, Italy.
authors.forename: Enea F
authors.initials: EF
authors.lastname: Pavone
authors.affiliation: Fondazione Santa Lucia, IRCCS, Via Ardeatina 306, Rome, Italy.|SCNLab, Department of Psychology, University of Rome "La Sapienza", Via dei Marsi, 00185, Rome, Italy.
authors.forename: Salvatore M
authors.initials: SM
authors.lastname: Aglioti
mesh_terms: D000328:Adult; D001831:Body Temperature; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D012881:Skin Temperature / Q000502:physiology*; D014584:User-Computer Interface; D000076142:Virtual Reality; D014796:Visual Perception / Q000502:physiology*
keywords: Immersive Virtual Reality; body ownership; first person perspective; thermal imaging; visual continuity