The Sense of Body Ownership and the Neural Processes of Memory Encoding and Reinstatement

Abstract

Every event we experience that results in a memory involves experiencing our conscious self at its heart. The spatial and perceptual experience of ones own body is the most basic form of selfhood. Disrupting bodily selfhood during memory formation impairs functioning of the hippocampus during retrieval, which implies a weakening of encoding mechanisms. However, neural activity present as individuals encode memories during manipulations of bodily selfhood have yet to be assessed. We investigated how body ownership, a core aspect of bodily selfhood, impacts encoding processes in the hippocampus and additional core memory regions (e.g. posterior parietal cortex). Further, we assessed the degree to which memories are reinstated according to body ownership during encoding and vividness during retrieval as a measure of memory strength. Participants viewed immersive videos through VR glasses, which depicted everyday events that included a first-person view of a mannequins body aligned with participants real bodies during fMRI scanning. We manipulated feelings of body ownership over the mannequin using a perceptual full-body illusion. One week later, participants retrieved memories for the videos during fMRI scanning. We observed that patterns of activity in several regions including the hippocampus and posterior parietal cortex distinguished between videos encoded with strong versus weak illusory body ownership. Moreover, these same regions reinstated memories to a greater degree when they were formed with a strong sense of body ownership and retrieved with increasing levels of vividness. Our findings demonstrate how the fundamental sense of owning ones body shape neural signatures of memory formation and strengthen reinstatement at retrieval.