Premotor cortex implements causal inference in multisensory own-body perception

Abstract

How do we come to experience our body as our own? When we look at our hands, for example, we immediately sense that they are part of our body. This experience of the limbs and other body parts being one’s own is referred to as the sense of “body ownership” (1). Body ownership allows us to quickly and accurately identify and localize our limbs in space and to discriminate between the physical self and the external world. However, how does the brain represent one’s own body, and what kind of processes mediate the sense of body ownership? An important realization is that we experience our body as a coherent combination of sensory experiences from our different sensory modalities (multisensory perception). When we move our hand in full view, for example, the visual impressions of the hand moving and the somatosensory sensations from the stretching skin and muscles are seemingly blended together into a unitary multisensory experience of a single hand. There is evidence that the multisensory coherence of bodily perception is critical for the sense of body ownership (1). A striking demonstration of this is the “rubber hand illusion” (2), in which the experimental manipulation of the spatial and temporal correspondences of visual and somatosensory information leads to the illusory sensation of a rubber arm being part of one’s own body. In its classic version, repeated synchronous strokes applied to a rubber hand, in full view, and to the participant’s real hand, which is hidden, elicit the illusion that the rubber hand is one’s own and that the model hand is capable of sensing the strokes one observes. It has been theorized that this illusion happens as a consequence of the brain’s perceptual systems, inferring that what one sees and what one feels are the same thing—one’s hand—leading to the … [↵][1]1To whom correspondence may be addressed. Email: henrik.ehrsson{at}ki.se. [1]: #xref-corresp-1-1