The Neural Correlates of Bodily Self-Consciousness in Virtual Worlds

Bodily Self-Consciousness (BSC) is the cumulative integration of multiple sensory modalities that contribute to our sense of self. Sensory modalities, which include proprioception, vestibulation, vision, and touch are updated dynamically to map the specific, local representation of ourselves in space. BSC is closely associated with bottom-up and top-down aspects of consciousness. Recently, virtual- and augmented-reality technology have been used to explore perceptions of BSC. These recent achievements are partly attributed to advances in modern technology, and partly due to the rise of virtual and augmented reality markets. Virtual reality head-mounted displays can alter aspects of perception and consciousness unlike ever before. Consequently, many strides have been made regarding BSC research. Previous research suggests that BSC results from the perceptions of embodiment (i.e., the feeling of ownership towards a real or virtual extremity) and presence (i.e., feeling physically located in a real or virtual space). Though physiological mechanisms serving embodiment and presence in the real world have been proposed by others, how these perceptual experiences interact and whether they can be dissociated is still poorly understood. Additionally, less is known about the physiological mechanisms underlying the perception of presence and embodiment in virtual environments. Therefore, five experiments were conducted to examine the perceptions of embodiment and presence in virtual environments to determine which physiological mechanisms support these perceptions. These studies compared performance between normal or altered embodiment/presence conditions. Results from a novel experimental paradigm using virtual reality (Experiment 4) are consistent with studies in the literature that reported synchronous sensorimotor feedback corresponded with greater strength of the embodiment illusion. In Experiment 4, participants recorded significantly faster reaction times and better accuracy in correlated feedback conditions compared to asynchronous feedback conditions. Reaction times were also significantly faster, and accuracy was higher for conditions where participants experienced the game from a first- versus third-person perspective. Functional magnetic resonance imaging (fMRI) data from Experiment 5 revealed that many frontoparietal networks contribute to the perception of embodiment, which include premotor cortex (PMC) and intraparietal sulcus (IPS). fMRI data revealed that activity in temporoparietal networks, including the temporoparietal junction and right precuneus, corresponded with manipulations thought to affect the perception of presence. Furthermore, data suggest that networks associated with embodiment and presence overlap, and brain areas that support perception may be predicated upon those that support embodiment. The results of these experiments offer further clues into the psychophysiological mechanisms underlying BSC