DARPA promised prosthetic limbs that produce realistic sensations, and it's making good on its word. The agency's researchers have successfully tested an artificial hand that gave a man a "near-natural" level of touch. The patient could tell when scientists were pressing against specific fingers, even when they tried to 'trick' the man by touching two digits at once. The key was to augment the thought-controlled hand with a set of pressure-sensitive torque motors wired directly to the brain -- any time the hand touched something, it sent electrical signals that felt much like flesh-and-bone contact.