Everyone knows what the “phantom pain phenomenon” is when a person is hurt by an absent, amputated limb. Believed that an imprint of a hand or foot is stored in the brain, and with this phantom the brain lives with something really existing. Researchers from Carolina Institute (Sweden) tried to create such a phantom sensation in a person without any amputations. Experiment passed as follows: a volunteer was seated at a table with a partition, one side from which the person laid his hand. He himself watched to the other half of the table, that is, I did not see my hand. The experimenter, sitting opposite, began to stroke his hand with a brush test subject. At the same time, on the other side of the partition, he did such the same stroking movements, and also with a brush, but – above an empty place. Himself but the experimental, we recall, did not see how stroking his real hand, since I looked only at symmetric stroking over the empty the place. 
Photos from open sources
Researcher strokes real and invisible brush hands on opposite sides of the screen. (Photo by the authors of the work.)
In an article published in the Journal of Cognitive Neuroscience, researchers write that within a minute a person had the feeling of an invisible hand, that is, stroking an empty place began to be felt in the brain. (The template for this feeling was as you can understand, real sensations from a real hand on the other side of the screen.) At some point, the experimenter took out a knife and thrust it into an empty place. At the same time, the volunteer was measured the level of stress, which at this provoking moment sharply jumped up. That is, it seemed to the subject that the knife would hurt him and he will feel pain. The existence of the phantom hand was confirmed and brain scan. Moreover, the further from the volunteer was this “hand”, the weaker the feeling. In other words, the phantom arose when the length of the imaginary arm was the same as the length hands of the present. To the same extent, the phantom sensation depended on coordination of movements: if an imaginary hand was stroked, for example, in a direction that did not coincide with stroking a real hand, the phantom sensation was negligible. Received the results suggest that the brain can create an image of the body without visual confirmation, relying only on tactile sensations. Perhaps further research on how the brain imagines body, will advance the creation of smart prostheses that a person can perceive as his own hands and feet. Prepared by materials Carolina Institute.
