Tech’s NeuroLab is melding man and machine

Illustration by Brett Weldele

When he was 8 years old, Andres Garcia went to the theater in his native Puerto Rico to see Star Wars: A New Hope for the first time. While most of his peers cowered as Darth Vader stomped onto the screen, Garcia was fascinated. The Dark Lord Vader was part man and part machine, biology and technology interwoven.

Darth Vader is science fiction. And yet, three decades after the character first appeared on screen, Garcia, a bioengineering professor in the Woodruff School of Mechanical Engineering, is refining implantable electrodes that create an integrated interface between the human brain and machines.

“I’m a child of Star Wars,” said Garcia, who watched A New Hope three times in the theater. “When I chose to go into engineering, it was with an eye toward that type of work. I’m a geek at heart.”

Elsewhere on Tech’s campus, researchers are using brain signals to allow paralyzed people to control motorized wheelchairs and wordlessly communicate. And a culture of rat neurons is controlling a robotic arm that’s halfway across the world.

This sounds like science fiction, but it’s the very real front line of brain-robotic interfacing. And Tech’s researchers are on the cutting edge of that field, which is set to become more advanced, and more pervasive, in the decades to come.

Garcia, a materials scientist, works closely with the Laboratory for Neuro-engineering, or NeuroLab, a multidisciplinary environment for cutting-edge research at the interface of technology and the nervous system.

The NeuroLab’s director, associate professor Steve Potter, pulled from a shelf in his office a book that predicts humans soon will achieve immortality by uploading their existences onto computers. Potter was quick to call the idea implausible, though his main sticking point was the word “soon.”

“It will be another century or two before we can record a person’s identity on a computer,” he said. “But it’s not long before we give people new senses. And I don’t mean just replacing lost senses, but giving people senses that are unnatural, like seeing in infrared. The imagination is the limit.”

Building the Cyborg

In 1960, scientists Manfred Clynes and Nathan Kline coined the term cyborg in an article on the future of space travel. They examined the possibility of creating a “cybernetic organism” designed to survive in extraterrestrial environments.

Scientists long have been using technology to compensate for injuries or disabilities. Crutches, eyeglasses, hearing aids and prosthetic limbs are just a few examples.

Only relatively recently, however, have researchers begun exploring what writer D.S. Halacy, in his 1965 book, Cyborg, called “the relationship between ‘inner space’ to ‘outer space’ — a bridge … between mind and matter.” In other words, technology began diving beneath the skin.

Advances in that area have begun making significant impacts. Cochlear implants in the inner ear use electrical signals to allow deaf people to hear. Deep brain stimulation is used to treat Parkinson’s disease.

“Technology should ideally become an extension of who we are, augmenting our capabilities,” said professor Ravi Bellamkonda, also a member of the NeuroLab. “Figuring out how to seamlessly integrate external electronics to biology has profound implications for our collective quality of life in the future.”

That research area was named a top priority when the Department of Biomedical Engineering was formed in 1997, leading to the creation of the NeuroLab, a voluntary partnership of nine faculty members from biomedical engineering and electrical and computer engineering. The researchers share space and graduate students, write joint grants and collaborate on ideas.

Members of the lab say partnership between faculty at Tech and at Emory University has been crucial to their early successes.

“It’s very challenging,” Garcia said. “But being able to work in an interdisciplinary environment will lead to significant developments more than if each group was working independently. We have access to all these world-class research groups, and Emory adds a strong dimension.”

Outside Looking In

Those who suffer from locked-in syndrome are conscious but unable to control any muscles. They cannot move their limbs or talk. Some cannot even blink.

Much of the focus in brain-technology interfacing is on people with such disabilities, to see if technology can allow the disabled once again to interact with the outside world.

Melody Moore Jackson, an associate professor in the College of Computing and director of the Center for BioInterface Research, dedicates much of her research to this effort.

Her research group uses infrared imaging, functional magnetic resonance imaging and other noninvasive technologies to “listen” as the neurons in the brain fire electrical charges across the cell membrane.

“The potential of implanted electrodes is higher, and it’s just astonishing,” Jackson said. “Those things will become more usable. Right now, we’re doing pretty well without opening up the head.”

In a healthy person, a certain pattern of neuron activity will stimulate the body to move in a certain way. Jackson said her research involves monitoring a disabled person’s brain as they imagine making that exact movement.

A major goal is to allow communication. Jackson flashes images on a screen and measures for brain activity that signals the person sees what they’re thinking about. Using that method, locked-in syndrome sufferers have 100 percent accuracy spelling out messages.

“It’s unbelievably satisfying to have someone who hasn’t been able to communicate finally tell their family that they love them,” Jackson said. “It’s amazing.”

Communication Breakdown

In Star Wars: The Empire Strikes Back, Luke Skywalker loses a hand only to have it quickly replaced with a cybernetic prosthetic. Such replacement limbs are becoming reality, with some robotic arms being deft enough to pluck a single grape from a bunch.

The key to perfectly integrating such prostheses will be linking them to the nervous system and brain. That challenge is the central focus of the NeuroLab.

One challenge to using implanted devices is that, over time, scar tissue and inflammation forms around the electrodes. That impedes the electrodes’ ability to detect neurons firing and to stimulate the neurons.

The Bellamkonda and Garcia research groups are collaborating to better understand the molecular interaction between electrodes and neurons in the hope of designing new interfaces that don’t irritate the brain cells.

Potter’s group has begun studying optogenetics. Neurons can be engineered to respond to certain colors of light, and fiber-optic wire, which is more biocompatible, can be used to stimulate the cells.

Garcia’s group is developing an electrode coating that cells don’t react negatively to. Using the coatings in tandem with anti-inflammatory agents such as steroids has led to early successes. But Garcia predicts it will be another three years at least before they achieve significant improvements.

“We will get there,” he said. “The question will be the time frame.”

Building Brains

Potter was a graduate student studying learning and memory and needed a test subject for research on neurons. He was considering worms or insects when he learned of neuron cell cultures grown in multielectrode arrays.

The arrays essentially are petri dishes lined with electrodes, which can interact with the neurons growing in the dish. And because the neurons are on a flat surface, they can be seen with a microscope while still living and firing.

That discovery pulled Potter into in vitro neuroscience and led him to become one of the leading researchers in neuron cultures and multielectrode arrays. The arrays are connected to a computer with software to monitor the neurons’ activity. Potter can send input back through the electrodes to stimulate the neurons.

One of the Potter group’s first projects was to give the neurons a body in a virtual world.

“At first it never did learn anything,” Potter said. “There would be these bursts of activity, and we hypothesized that was because it was cut off from all input, and those bursts wiped out its memory.”

The researchers limited the bursts by sending back a small amount of activity through the electrodes. Quickly, the neurons began learning. Before long, they could stimulate the neurons to move the virtual character in specific ways. It was the first time scientists had trained a neuron culture.

Now, the cultures are used in projects such as MEART, the “semi-living artist.” The Potter group’s neuron cells communicate through the Internet with a robotic arm in Australia. The arm, equipped with felt markers, creates elaborate drawings based on how the cells are stimulated.

Beyond controlling robots, the group’s discovery also led in an unexpected direction. They realized the bursts of activity in neurons might relate to epilepsy. Partnering with Robert Gross, an associate professor of neurosurgery at Emory, Potter’s group is studying whether small amounts of feedback through electrodes could prevent such damaging bursts.

“You have to be open-minded, especially when things don’t go right,” Potter said. “Some of the biggest advances in science came from experiments that went wrong.”

The lab is exploring other potential benefits of brain stimulation. Potter said it could be used to treat Alzheimer’s disease, addiction, overeating and depression. “Why wouldn’t people do it if they can flip a switch and be not depressed?”

Another potential use for the neuron cultures is in artificial intelligence, Potter said. His group is partnering with power engineering researchers to use the cultures to teach artificial networks how to respond more quickly to power surges and outages.

“We think they’ll be better at real-time control because animals are great at that,” he said. “That’s a big-picture goal, to make computers more brain-like.”

The Brain’s Language

Looking at the development of robotic prosthetic limbs, Potter notices one glaring problem: They’re numb.

“We focus so much on the six senses, but we don’t value proprioception, which is the sense of where parts of the body are in relation to each other,” he said. “You absolutely depend on this. People are very clumsy without it.”

To develop robotic limbs as effective as Darth Vader’s, researchers not only need to detect signals coming from the brain but also to send feedback from the limb to the brain.

When neurons don’t receive feedback, they eventually slow or stop firing and the synaptic connections weaken. Potter’s hypothesis is that neurons are like a person lost in a pitch-black room. If they shout for help for long enough without a response, they stop shouting entirely.

The critical issue, then, is learning how to send signals back into the brain. But Potter says scientists are still far from understanding the brain’s language. Neurons fire every millisecond and may work collectively. In addition, glial cells are believed to transmit chemical signals, adding another layer of complexity.

If researchers were able to record data from just a portion of one human brain for a limited time it would fill every hard drive on Earth, Potter said.

“People are vastly underestimating how complicated the brain is and how much information is between your ears,” he said.

Increasing Interaction

Even if a true fusion between biology and technology remains only in science fiction, members of the NeuroLab are convinced it is on the horizon.

Potter said he expects brain interfacing to expand beyond treating illnesses and disabilities. One possible use is to stimulate learning and limit forgetting, he said.

“Neuro-engineering is going to touch everybody,” he said, “if not within five years, then within 10.”

Garcia imagined a world of absolute integration between humanity and technology.

“For instance, you can have an outlet in your head to drive your car without a steering wheel,” he said. “Certainly, that’s farther in the future. But the progress is going that way.”