- image via arstechnica.com

The motor cortex has several areas, but the primary motor cortex, a strip of brain just behind the frontal lobe, is where you decide to send out signals to peripheral nerves to tell your arms or legs to do something. The cortex is also organized somatotopically: the region that controls the feet is next to that which controls the leg, then trunk, arm, and so on. The practical upshot of this is that we have a good idea which region of the primary motor cortex needs to be measured in order to work on controlling a cybernetic arm or hand.

Microelectrodes were implanted in the regions that control part of the monkeys’ arm, and they were trained to use neural activity to control the prosthetic arm. Since you can’t really give a monkey instructions, this was achieved by training the monkeys with a one-dimensional joystick; as they pushed the joystick, the arm would move. After several days, the monkeys had enough control with the joystick to retrieve food and feed themselves. Over time, the input from the joystick was reduced and cortical control was developed.

Previous experiments centered on using the primary motor cortex as a brain/computer interface have used cortical activity to control a cursor on a screen. This study instead uses brain activity to control a physical object that the monkey can interact with. The authors argue that this added factor is a major element of their success, and that it bodes well for the development of neurally-controlled artificial limbs. Cortical control, combined with tactile feedback similar to that described last year, should make for functional cybernetic limbs with a minimum of wires protruding from one’s scalp.

Link via arstechnica.com

I would like to see a picture of the monkeys in action.

Update: The New York Times has a video availible.