Brain-controlled prosthetics that enable a person to, say, pick up a pencil continue to improve for amputees, but limbs that can actually feel touch sensations have remained a challenge. Now researchers led by neuroscientist Miguel Nicolelis of Duke University in Durham, North Carolina, have created a virtual prosthetic arm that monkeys control using only their minds, and that enables them to feel virtual textures. To “close the loop” between controlling a limb and feeling physical touch, the researchers implanted two sets of tiny electrodes into a monkey’s brain: one set in the motor control center, and the other in the part of the somatosensory cortex that processes the sensation of physical touch either from the left hand or the leg. Using the first set, the monkey could control a virtual monkey arm on a computer screen and sweep the hand over virtual disks with different “textures.” The second set of electrodes fed a series of electrical pulses (low frequency for rough texture, high frequency for fine texture) into the touch center of its brain. With little training, the monkeys could consistently distinguish the textures as if the arm was their own, the team reported 5 October in Nature.
SOURCE : SCIENCE MAGAZINE VOL 334