Figure 1
Experimental setup and procedures. (A) Participants were immersed through an HMD at the centre of a 7 × 4 m virtual room. An avatar was shown 2 m in front of the participants at the centre of the room. (B) During visuo-tactile stimulation, the experimenter stroked the back of the participants with a controller while its movement was synchronously or asynchronously reproduced by a virtual controller on the back of the avatar. Participants wore a motion tracker at the waist to record their position during the locomotion task (LT). They held a controller in their right hand to answer during the mental imagery task (MIT) and to answer the questionnaires. (C) A block of MIT comprised the following events: (1) Baseline measurement of the skin temperature during 6 s; (2) 2 min of synchronous or asynchronous visuo-tactile stimulation. (3) A beep indicates the onset of the MIT, followed by (4) the apparition of a red ball in front of the participants, in the end of the room, which rolled at constant speed toward “them” during 3 s. (5) A black screen appeared and participants imagined the ball rolling toward them and (6) they indicated when they thought that the ball had arrived at their position, by pulling the controller’s trigger. (7) The answer to the localization task triggered the presentation of a questionnaire. (D) Participants used their controller to direct a virtual laser to one of the levels of a Likert scale ranging from “Totally disagree” to “Totally agree”.
