Behavioral and neural aspects of the vestibular influence on bodily self consciousness

Abstract

The experience of having a body is the key aspect for self-consciousness and it has been recognized that such a coherent bodily self relies on ongoing multisensory integration of bodily sensory inputs. A coherent bodily self is mostly taken for granted, despite being highly influenceable. To induce comparable bodily illusions in healthy participants, experimental paradigms have been developed that mostly rely on visuotactile conflicts. Although the involvement of the vestibular system in multisensory integration is supposed to be crucial for global aspects of bodily self-consciousness, only few studies tested this hypothesis experimentally. Thus, in the first study of this thesis it was examined how visuo-vestibular conflicts influence body ownership, a core feature of bodily self-consciousness. Physiological parameters indicated a stronger body ownership over a fake body during the induction of visual-vestibular conflicts. In a second study, we examined the implicit perception of complete and amputated bodies in individuals with a peculiar disorder of bodily self consciousness. We showed that in comparison to controls, individuals with this disorder preferred amputated bodies. In a third study, we investigated whether natural vestibular stimulation would alter pain thresholds, as the analgesic effect of artificial vestibular stimulation has been shown previously. We found that natural vestibular stimulation increased pain thresholds, but so did the control conditions.