Disentangling the Neural Correlates of Agency, Ownership and Multisensory Processing

Abstract

The experience of the self as an embodied agent in the world is an essential aspect of human consciousness. This experience arises from the feeling of control over ones bodily actions, termed the Sense of Agency (SoA), and the feeling that the body belongs to the self, Body Ownership (BO). Despite long-standing philosophical and scientific interest in the relationship between the body and brain, the neural systems involved in SoA and BO and especially their interactions, are not yet understood. In this preregistered study using the Moving Rubber Hand Illusion inside an MR-scanner, we aimed to uncover the relationship between BO & SoA in the human brain. Importantly, by using both visuomotor and visuotactile stimulations and measuring online trial-by-trial fluctuations in the illusion magnitude, we were able to disentangle brain systems related to objective sensory stimulation and subjective judgments of the bodily-self. Our results indicate that at both the behavioral and neural levels, BO and SoA are strongly interrelated. Multisensory regions in the occipital and fronto-parietal regions encoded convergence of sensory stimulation conditions. However, the subjective judgments of bodily-self were also related to BOLD fluctuations in regions not activated by the sensory conditions such as the insular cortex and precuneus. Our results highlight the convergence of multisensory processing in specific neural systems for both BO and SoA with partially dissociable regions for subjective judgments in regions of the default mode network.