Artificial brain-muscle connections restore monkeys' hand movement after paralysis

London, April 19 (ANI): Researchers have found that an artificial connection between the brain and muscles can restore complex hand movements in monkeys following paralysis.

The research team led by Lee E. Miller, Ph.D., professor of physiology at Northwestern University's Feinberg School of Medicine in Chicago, describe how they combined two pieces of technology to create a neuroprosthesis - a device that replaces lost or impaired nervous system function.

One piece is a multi-electrode array implanted directly into the brain, which serves as a brain-computer interface (BCI).

The array allows researchers to detect the activity of about 100 brain cells and decipher the signals that generate arm and hand movements.

The second piece is a functional electrical stimulation (FES) device that delivers electrical current to the paralysed muscles, causing them to contract. The brain array activates the FES device directly, bypassing the spinal cord to allow intentional, brain-controlled muscle contractions and restore movement.

Prior to testing the neuroprosthesis, Dr. Miller's group recorded the brain and muscle activity of two healthy monkeys as the animals performed a task requiring them to reach out, grasp a ball, and release it.

The researchers then used the data from the brain-controlled FES device to determine the patterns of muscle activity predicted by the brain activity.

To test the device, the researchers gave monkeys an anesthetic to locally block nerve activity at the elbow, causing temporary paralysis of the hand. With the aid of the neuroprosthesis, both monkeys regained movement in the paralysed hand, could pick up and move the ball in a nearly routine manner and complete the task as before.

Dr. Miller's research team also performed grip strength tests, and found that their system restored precision grasping ability. The device allowed voluntary and intentional adjustments in force and grip strength, which are keys to performing everyday tasks naturally and successfully.

This new research moves beyond earlier work from Dr. Miller's group showing that a similar neuroprosthesis restores monkeys' ability to flex or extend the wrist despite paralysis.

"With these neural engineering methods, we can take some of the important basic physiology that we know about the brain, and use it to connect the brain directly to muscles," Dr. Miller said.

"This connection from brain to muscles might someday be used to help patients paralysed due to spinal cord injury perform activities of daily living and achieve greater independence," the researcher added.

The study was reported in the journal Nature. (ANI)