Quantifying Self Perception: Multisensory Temporal Asynchrony Discrimination As A Measure of Body Ownership

There are diffuse and distinct cortical networks involved in the various aspects of body representation that organize information from multiple sensory inputs and resolve conflicts when faced with incongruent situations. This coherence is typically maintained as we maneuver around the world, as our bodies change over the years, and as we gain experience. An important aspect of a congruent representation of the body in the brain is the visual perspective in which we are able to directly view our own body. There is a clear separation of the cortical networks involved in seeing our own body and that of another person. For the projects presented in my dissertation, I used an experimental design in which participants were required to make a multisensory temporal asynchrony discrimination after self-generated movements. I measured sensitivity for visual delay detection between the movement (proprioceptive, efferent and afferent information) and the visual image of that movement under differing visual, proprioceptive, and vestibular conditions. The self-advantage is a signature of body ownership and is characterized by a significantly lower threshold for delay detection for views of the body that are considered self compared to those that are regarded as other. Overall, the results from the collection of studies suggest that the tolerance for temporally matching visual, proprioceptive and efferent copy information that informs about the perceived position of body parts depends on: whether one is viewing ones own body or someone elses; the perspective in which the body is viewed; the dominant hand; and the reliability of vestibular cues which help us situate our body in space. Further, the self-advantage provides a robust measure of body ownership. The experiments provide a window on and support for the malleable nature of the representation of the body in the brain.