From Scientific American:
Where are you right now? Maybe you are at home, the office or a coffee shop—but such responses provide only a partial answer to the question at hand. Asked another way, what is the location of your “self” as you read this sentence? Like most people, you probably have a strong sense that your conscious self is housed within your physical body, regardless of your surroundings. But sometimes this spatial self-location goes awry. During a so-called out-of-body experience, for example, one's self seems to be transported outside the physical body into a surreal perspective—some people even believe they are viewing their bodies from above, as though their true selves were floating. In a related experience, people with a delusion known as somatoparaphrenia disown one of their limbs or confuse another person's limb for their own. Such warped perceptions help researchers understand the neuroscience of selfhood.
A new paper offers examples of rare bodily illusions that are not confined to a single limb, nor are they complete out-of-body experiences—they are somewhere in between. These illusory body perceptions, described in the September issue of Consciousness and Cognition, could offer novel clues about how the brain maintains a link between the physical and conscious selves, or what the researchers call “bodily self-consciousness.”