Electric Wire Bypasses Peripheral Nerves To Control Muscles

Monkeys trained to stimulate neurons which have embedded electrodes could control wrist muscle contractions using a sort of primitive "fly-by-wire" system.

Researchers in a study funded by the National Institutes of Health (NIH) have demonstrated for the first time that a direct artificial connection from the brain to muscles can restore voluntary movement in monkeys whose arms have been temporarily anesthetized. The results may have promising implications for the quarter of a million Americans affected by spinal cord injuries and thousands of others with paralyzing neurological diseases, although clinical applications are years away.

This isn't just useful for people who have spinal cord injuries. Direct neural interfaces that can control one's own muscles could also control heavy equipment such as airplanes. Also, the ability to control one's own muscles via an artificial route that bypasses spinal nerve pathways could allow one to control one's extremities much more quickly. The wave of depolarization that transmits a pulse down a nerve's membranes is pretty slow compared to the speed of electrons in a wire.

"This study demonstrates a novel approach to restoring movement through neuroprosthetic devices, one that would link a person's brain to the activation of individual muscles in a paralyzed limb to produce natural control and movements," said Joseph Pancrazio, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke (NINDS). The research was conducted by Eberhard E. Fetz, Ph.D., professor of physiology and biophysics at the University of Washington in Seattle and an NINDS Javits awardee; Chet T. Moritz, Ph.D., a post-doctoral fellow funded by NINDS; and Steve I. Perlmutter, Ph.D., research associate professor. The results appear in the online Oct. 15 issue of Nature. The study was performed at the Washington National Primate Research Center, which is funded by NIH's National Center for Research Resources. In the study, the researchers trained monkeys to control the activity of single nerve cells in the motor cortex, an area of the brain that controls voluntary movements. Neuronal activity was detected using a type of brain-computer interface. In this case, electrodes implanted in the motor cortex were connected via external circuitry to a computer. The neural activity led to movements of a cursor, as monkeys played a target practice game.

Of course, if electrodes get implanted into a person's muscles this creates the possibility of remote control of a person's muscles. A guy could get kidnapped and given secret surgery to implant a radio receiver and wiring to some of his peripheral muscles. The first time he finds out about what his kidnappers did is when he grabs a gun from a security agent and finds himself powerless to stop from shooting a top political leader. Other possibilities come to mind with husbands who get tired of hearing their wives gossip.

After each monkey mastered control of the cursor, the researchers temporarily paralyzed the monkey's wrist muscles using a local anesthetic to block nerve conduction. Next, the researchers converted the activity in the monkey's brain to electrical stimulation delivered to the paralyzed wrist muscles. The monkeys continued to play the target practice gameonly now cursor movements were driven by actual wrist movementsdemonstrating that they had regained the ability to control the otherwise paralyzed wrist.

Picture mini-electrodes in your brain tied to a transmitter. You could send messages to many devices in your environment including a garage door, a car ignition, or the thermostat in a house. I expect human-machine interfaces will become far more powerful in the future.