Effects of shifting perspective of the self: an fMRI study

When looking to our reflection, or moving a video-game character, we see our own movement preformed by an agent which is physically separated from our body. Yet, we consider the agent to be ourself. Using fMRI, we sought to explore the neural underpinnings of disembodiment, the cognitive mechanism under which the properties of the self are projected away from the boundaries of one's own body towards an external entity. Seventeen participants watched a video-game in which three players threw each other a ball. Subjects' key-press could either be synchronous or asynchronous with one of the players' action (TASK: Agency vs. Control). The game was shown from one of four viewpoints which could either be fixed or change every trial (VIEWS: Fixed vs. Changeable). Consistent with previous studies, the left insula was activated when the agent's movements were synchronous with those of the participants (main effect of TASK, p<0.05, SVC). The analysis of the interaction TASKVIEWS revealed activation (p<0.05, corrected) of the right parieto-temporal-occipital (PTO) junction when the agent whose movements were synchronous to the participants was processed in a spatial position each time different with respect to the preceding trials. Our findings implicate the right PTO junction in assigning one's own movements to an agent which is physically independent of oneself. They also suggest that the ability to disembody, and thereby objectify, bodily or mental states concerning the self is common to all experimental paradigms which led to an activation of the PTO junction.