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When brain signals are turned into a computer formula, those signals can move a computer cursor with the power of thought.


Movement through the power of the mind

by Bethany Hubbard
May 19, 2011


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Bethany Hubbard/MEDILL

The Hatsopoulos Lab at the University of Chicago uses brain-machine interfaces to record neural activity in the brain.

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Statistics courtesy of the National Spinal Cord Injury Statistical Center

Innovative research is harnessing the power of the mind to give paraplegics a new way to imitate motion and operate a computer. When a person just thinks about movement via sensors, signals from the brain are translated into what is essentially a computer code that programs a cursor. Think left and the cursor moves in that direction.

The research still being done in the lab could allow people to use computers or operate wheelchairs and perform other tasks without actually using their hands.

Brain-machine interfaces are devices that record neural activity in the brain. Such devices can use an array, or chip, that is implanted in the brain (ECoG). The alternative is to rely on EEG, the recording of electrical activity along the surface of the scalp.

“The primary difference between all of the methods is that the ECoG and EEG electrodes are recording from millions or tens of millions of neurons at a time, whereas these penetrating micro-electrodes are recording from a single or small groups of neurons,” said J. Adam Wilson of The University of Cincinnati.

This is one of several institutions, including The University of Chicago, where pioneering research in "motor-memory" and brain-machine interfaces is ongoing.

By mapping how the neurons contribute to specific movements, scientists then create a formula for motion. The formula is plugged into a computer, and movement can be electronically recreated in the form of a cursor on a screen.

A paraplegic who has lost control of his arms, when hooked up to a computer via an array, can move a cursor on a computer screen simply by thinking – something that has already been successfully demonstrated through BrainGate technology.

The BrainGate2 research team, out of Brown University, is the second edition of the original trial team, and “includes leading neurologists, neuroscientists, engineers, computer scientists, neurosurgeons, mathematicians, and other researchers – all focused on developing technologies to restore the communication, mobility, and independence of people with neurologic disease, injury, or limb loss,” according to their website.

Right now, the technology is not quite ready for mainstream use.

“I think brain-computer interfaces in general currently are a little too unpredictable or not reliable enough to be used by the general public,” Wilson said. “There is plenty of research going looking at how the brain-computer interfaces can be marketed for games or for general purpose use. But the primary goal is to give people who are locked in the means to communicate.”

For scientists, motor memory, the memory of movement, has always been somewhat of a mystery.

Nicholas Hatsopoulos, of the University of Chicago, uses brain-machine interfaces in his lab to study movement. He was a founder of Cyberkinetics Neurotechnology Systems that pioneered the BrainGate technology.

He said that it is likely that motor memory is highly distributed throughout the brain. Thus, the memory of a dance move, or baseball throw, is not stored in one specific place, but spread out throughout many regions. This is unlike the somatosensory cortex, which houses sensory input.

“You can touch the skin and you’ll see cells in particular parts of the somatosensory cortex that light up,” said Hatsopoulos, who is mapping out this area of the brain with a colleague.

In the past, scientists believed that movement worked in a similar way – that there was a particular spot in the primary motor cortex for each individual finger.

However, current research suggests otherwise. While no reason has been scientifically determined, Hatsopoulos believes that it is because movement relies on the cooperation of many different joints.

“Most movements don’t involve single digits. They’re complex. They’re not isolated,“ he said.

To throw a baseball, you don’t just use one finger. Thus, the neurons for all fingers involved, and for the hand and arm, must be activated – must be close to one another in order to be most effective. If they are highly distributed, they can more easily work together.

A better understanding of how motor memory is stored could promise paraplegics a better quality of life.

According to the National Spinal Cord Injury Statistical Center, in Birmingham, Ala., there are approximately 12,000 new cases of spinal cord injury every year. Such debilitating injuries are not only life changing, but costly. Some families may spend nearly $1 million in the first year of care for those who are most severely injured.

Brain-machine interfaces might even be used for non-medical purposes in the future.

Tim Bretl is an assistant professor of Aerospace Engineering at the University of Illinois at Urbana-Champaign, and a member of the school’s Brain-Machine Interface Group. He uses EEG technology to have subjects fly small fixed-wing unmanned aircrafts. Bretl said that there is still a lot to learn about the technology.

“These brain-computer interfaces are so complicated,” Bretl said. “There are so many unknowns still. It’s very difficult, like any complex system, to know which part of the system is important.”

A couple of Bretl’s students are spending the summer at the Rehabilitation Institute of Chicago to take such work in a medical direction.

“The idea is to try to take some of these concepts, these ideas, and bring them closer to clinical practice,” he said.

At The Neural Interface Technology Research and Optimization (NITRO) Lab at the University of Wisconsin-Madison, brain-machine interfaces have been used in conjunction with social media. Through the noninvasive EEG devices, researchers were able to send tweets via thought.

Wilson, a doctoral student on the lab team of biomedical engineer Justin Williams, posted the infamous tweet, “USING EEG TO SEND TWEET.” It caused quite a media frenzy.

“Right now it is kind of a novelty. I do think that this type of technology, kind of a virtual spelling system where someone who is completely locked in could use a brain-computer interface to communicate, is obviously certainly very useful,” he said.

Wilson is now a fellow at the University of Cincinnati Department of Neurosurgery, part of the College of Medicine. He is still using brain-machine interface research to help patients with epilepsy.

While such technology aims to help those with medical disabilities, Wilson said that it still might be awhile before we are all using such devices to post our daily tweets.