title: Imagined body orientation and perception of the visual vertical.
abstract: The existence of body orientation mental imagery was tested by examining whether self roll tilt imagery affects the subjective visual vertical (SVV). Twenty healthy subjects judged the orientation of a dim luminous bar with respect to gravitational vertical, while normally seated in complete darkness with their head firmly restrained earth vertically. SVV was measured in three conditions: a reference condition with no imagery, and a left and a right imagery condition, during which the bar orientation was to be judged while the subjects imagine themselves roll-tilted towards left or right, respectively. The imagined roll tilts were of the same magnitude as roll tilts which generally induce an E-effect, i.e., an SVV lean toward the side opposite to those of body tilt. If imagery and perception of self roll tilt share common processes, self roll tilt imagery should induce an E-like effect. Results show an imagery-induced E-like effect, which strongly supports the idea that humans can perform mental imagery of body orientation about gravity.
authors.affiliation: LENA, CNRS UPR 640, Unité de Neurosciences cognitives et Imagerie Cérébrale, Hôpital de la Salpêtrière, 47 Boulevard de l'Hôpital, 75651 Paris, France. sophie.mertz@chups.jussieu.fr
authors.forename: S
authors.initials: S
authors.lastname: Mertz
authors.forename: J C
authors.initials: JC
authors.lastname: Lepecq
mesh_terms: D000328:Adult; D006801:Humans; D007092:Imagination / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D011601:Psychophysics; D014796:Visual Perception / Q000502:physiology*