Scientists tap brain signals to help paralyzed hand move

Using computer, electrode array and algorithms to let brain directly signal muscles

Researchers at Northwestern University have developed a device they say can deliver messages from the brain directly to muscles -- skipping over the spinal cord -- and enable a paralyzed hand to move.

Scientists hope the device, which so far has been tested on monkeys, will someday help people with various levels of paralysis move again.

"We are eavesdropping on the natural electrical signals from the brain that tell the arm and hand how to move, and sending those signals directly to the muscles," Lee E. Miller, professor in neuroscience at Northwestern University Feinberg School of Medicine, said in a written statement. "This connection from brain to muscles might someday be used to help patients paralyzed due to spinal cord injury perform activities of daily living and achieve greater independence."

Miller is the lead investigator of the study.

The researchers designed a tiny implant, which is a multi-electrode array designed to detect the activity of about 100 neurons in the brain. The array also acts as the interface between the brain and a computer which is used to decipher the signals that generate hand or limb movements.

"We can extract a remarkable amount of information from only 100 neurons, even though there are literally a million neurons involved in making that movement," Miller said. "One reason is that these are output neurons that normally send signals to the muscles. Behind these neurons are many others that are making the calculations the brain needs in order to control movement. We are looking at the end result from all those calculations."

This research follows work that was done in 2008 at Duke University. Researchers there reported then that they had worked with scientists in Japan to use the neurons in a monkey's brain to control a robot.

With that research, as well, scientists, who had been working on the project for 10 years, were hoping it would lead to finding a way to help the paralyzed walk and use their arms and hands again.

Late in 2007, a scientist who successfully connected a moth's brain to a robot predicted that between 2017 and 2022, people will be using "hybrid" computers -- a combination of technology and living organic tissue.

Charles Higgins, an associate professor at the University of Arizona, built a robot that is guided by the brain and eyes of a moth. Higgins said he strapped a hawk moth to the robot and then put electrodes in the neurons that deal with sight in the moth's brain. Then the robot responded to what the moth was seeing. For instance, when something approached the moth, the robot moved out of the way.

In the most recent research project at Northwestern University, scientists used implanted electrodes to record a monkey's electrical brain and muscle signals when they grasped a ball, lifted it and dropped it into a tube. Researchers then used the record of those signals to develop an algorithm to process future brain signals and predict the muscle activity needed to perform specific functions.

The university reported that the scientists gave the monkeys a localized anesthetic to block nerve activity at the elbow, causing temporary, painless hand paralysis.

"The monkey won't use his hand perfectly, but there is a process of motor learning that we think is very similar to the process you go through when you learn to use a new computer mouse or a different tennis racquet," Miller said. "Things are different and you learn to adjust to them."

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at  @sgaudin, on Google+ or subscribe to Sharon's RSS feed . Her email address is

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Copyright © 2012 IDG Communications, Inc.

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