Research: body ownership

27 March 2006

The feeling of body ownership is associated with many different sensory signals, not just vision.

In the 'rubber hand illusion', someone can be made to believe that a fake hand being rubbed in front of them is their own, if their own (hidden) hand is rubbed at the same time.

The trick is associated with activity in several areas in the brain, particularly the ventral premotor cortex. The significance of this activity is unclear, however – the phenomenon could mainly be due to the powerful effects of the visual system.

Now Dr Henrik Ehrsson and colleagues at the Wellcome Department of Imaging Neuroscience at UCL have eliminated the visual input, by blindfolding subjects. The team used the subject's own left hand to stroke the rubber hand, while simultaneously stroking the subject's right hand. After about ten seconds, subjects perceive that they are stroking their own hand.

Functional magnetic resonance imaging showed that specific, separate parts of the brain, including the ventral premotor cortex, were involved in the illusion, and the stronger the sensation, the greater the activity. This suggests that the sensation of body ownership is due to a range of sensory signals from the body, not just vision.

External links

• Ehrsson HH et al. Touching a rubber hand: feeling of body ownership associated with activity in multisensory brain areas. J Neurosci 2005;25(45):10564–73.