Bodily self-consciousness (BSC) can be altered by exposing subjects to ambiguous multisensory stimuli of one’s body’s appearance and location [1,2]. In the somatic rubber hand illusion (sRHI) [3], a blindfolded participant passively strokes a rubber hand while the experimenter synchronously touches the participant’s other hand. This tactile-proprioceptive conflict is resolved by integrating the simultaneous tactile stimuli into a unitary percept, resulting in the illusion of touching one’s own hand (self-touch) and mislocalization of the stroked hand towards the rubber hand. Based on previous BSC work concerning full body representations [2], we aimed to induce illusory self-touch at the trunk and observe changes in self-location.
Blindfolded participants (n=36, 19 females) moved the master device of a robotic telemanipulator in front while the slave part applied tactile feedback to their back. In two experiments we manipulated the Delay between the participants’ arm movements and tactile feedback, Resistance Force at the master device, and Movement Type (active/passive movement). Illusory self-touch was measured via questionnaires and self-location with a motor imagery task [4].
We found that illusory self-touch depended on the synchrony between the participant’s arm movements and tactile feedback. Synchrony also resulted in forward self-location drift, suggesting a remapping of self-location towards the location of illusory self-touch (master device). Our data demonstrate that changes in BSC affecting the full body and its experienced position in space can be induced experimentally in the absence of visual input. These changes were induced despite the strong spatial incongruence between arm’s sensorimotor signals and trunk somatosensory feedback.

sensorimotor integration; illusory self-touch; body representation