title: Direct coupling of haptic signals between hands.
abstract: Although motor actions can profoundly affect the perceptual interpretation of sensory inputs, it is not known whether the combination of sensory and movement signals occurs only for sensory surfaces undergoing movement or whether it is a more general phenomenon. In the haptic modality, the independent movement of multiple sensory surfaces poses a challenge to the nervous system when combining the tactile and kinesthetic signals into a coherent percept. When exploring a stationary object, the tactile and kinesthetic signals come from the same hand. Here we probe the internal structure of haptic combination by directing the two signal streams to separate hands: one hand moves but receives no tactile stimulation, while the other hand feels the consequences of the first hand's movement but remains still. We find that both discrete and continuous tactile and kinesthetic signals are combined as if they came from the same hand. This combination proceeds by direct coupling or transfer of the kinesthetic signal from the moving to the feeling hand, rather than assuming the displacement of a mediating object. The combination of signals is due to perception rather than inference, because a small temporal offset between the signals significantly degrades performance. These results suggest that the brain simplifies the complex coordinate transformation task of remapping sensory inputs to take into account the movements of multiple body parts in haptic perception, and they show that the effects of action are not limited to moving sensors.
authors.affiliation: Laboratoire Psychologie de la Perception, CNRS and Université Paris Descartes, 75006 Paris, France; and lucile.dupin@parisdescartes.fr.
authors.forename: Lucile
authors.initials: L
authors.lastname: Dupin
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Unité Mixte de Recherche 7222, Institut des Systèmes Intelligents et de Robotique, 75005 Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Hayward
authors.affiliation: Laboratoire Psychologie de la Perception, CNRS and Université Paris Descartes, 75006 Paris, France; and.
authors.forename: Mark
authors.initials: M
authors.lastname: Wexler
mesh_terms: D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D008960:Models, Psychological; D009039:Motion Perception / Q000502:physiology; D009068:Movement / Q000502:physiology; D055698:Touch Perception / Q000502:physiology*; D055815:Young Adult
keywords: haptics; kinesthesis; perception; sensorimotor integration; touch