Artificial sensibility of the hand based on cortical audiotactile interaction: a study using functional magnetic resonance imaging.

The capacity of the central nervous system for plastic alterations is the base for our ability to adapt to environmental needs. The crossmodal capacity of the brain makes interaction between senses possible, and deprivation of one sense leads to compensatory changes in other senses. We have recently shown how hearing can substitute for sensation in a transplanted insensitive hand by using a sensor glove equipped with small microphones that pick up the sound of friction, which is elicited by active touch. Here we have used functional magnetic resonance imaging (fMRI) in healthy people to illustrate their capacity for cortical audiotactile interaction with activation of the somatosensory cortex induced by auditory stimuli. The phenomenon occurred only in subjects trained to substitute sensibility by hearing, and no audiotactile interaction was found in untrained subjects.