Mechanisms underlying embodiment, disembodiment and loss of embodiment

Bodily experience is a complex, mostly unconscious, process that requires the integration of multiple sensory inputs. This paper reviews the sensory systems involved in internal representations of the body--primarily the proprioceptive, motor, vestibular, and visual systems. Various neurological disorders are defined by aberrations in bodily experience--including the perceptual ablation or disembodiment of body parts, "filling in" of amputated body parts, or reduplication of body parts. These perceptual aberrations are discussed and their implications for the central and peripheral systems involved in updating and retrieving internal representations of the body are highlighted. Bodily perception and egocentric frames of reference can be experimentally manipulated through visual capture (e.g., using rubber limbs), functional adaptation and embodiment of tools and prostheses, and changes in afferent sensory feedback (e.g., through stimulation of muscle spindles). These perceptual illusions are described, and discussed for their implications for the mechanisms underlying bodily perception.