Bionic Bodies: Why the Future for Quadriplegics Looks So Bright

The researcher who figured out how monkeys could manipulate virtual objects turns to a new challenge: helping quadriplegics walk by 2014


In the latest of a series of science fiction-like advances over the last few years, researchers from Duke University have discovered a way to allow monkeys not only to manipulate virtual objects but to detect texture with a virtual arm. This research is part of a project called Walk Again, in which international teams have collaborated to develop a gadget that will allow people with spinal cord injuries to walk, interact with, and, perhaps most importantly, to feel the contours and textures of the world around them.

The technology involves a complicated marriage of neuroscience and physics. In the new study, the research team, led by neurophysiologist Miguel Nicolelis, used a "brain-machine-brain" interface to allow monkeys to sense textures that didn't actually exist. They placed arrays of microelectrodes in two regions of monkeys' brains: the motor cortex, which controls intentional movement, and the somatosensory cortex, which governs how animals sense the external world.

A computer recorded the "intentions" of the monkeys' motor cortices, which allowed the monkeys to control an avatar arm with thoughts (neuronal activity) alone. The virtual arms contacted virtual objects, which were identical visually but differed in texture. The surfaces of the virtual objects sent back signals to the cells of the monkeys' somatosensory cortices, allowing them to perceive the texture discrepancy in these "feeling" areas of the brain.

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"We sent texture information to the region of the brain where tactile information is processed," Nicolelis says. "The animal was able to distinguish textures. Nobody has been able to achieve this until now. With this technology, we established a bidirectional link between brain and virtual object."

The technology is also impressive because it records the activity of a thousand neurons at once. "Most methods are only able to record 50-100 cells at a time," Nicolelis says, "so this is an order of magnitude greater, and allows us to do much more sophisticated manipulations."

These discoveries are a boon to the area because tactile feedback presents a far superior means to using visual feedback, and in this way it opens some interesting avenues for prosthetic development. Much of how we interact with the world relies on the constant flow of incoming physical information, which is much more reliable than visual feedback. When you're getting up from a chair, for example, you rely on your body cues to tell you whether you've done so successfully -- your eyes are of relatively little help in the process.

Nicolelis and colleagues have already shown that monkeys can manipulate objects with a robotic arm just by using their brains. Merging the research demonstrating physical manipulation of objects with the new research demonstrating virtual tactile feedback -- and shortly, physical feedback from an actual object -- will be the next projects.

"There are many intermediate steps," Nicolelis says, "but ultimately we want to make someone walk again. We'll soon demonstrate that we can control full body movement. We've already shown robotic movement of upper and lower limbs, and monkeys have used cortical activity to manipulate objects."

The final product sounds more like the imaginings of Dr. Octavius: A fully functional exoskeleton, manipulated through connections to the patient's motor and somatosensory cortices. "The ultimate goal," Nicolelis says, "is to build a robotic vest for the whole body. Just as in this study, a person's brain activity will control movement of the limbs, and get sensory feedback from the external world."

This kind of technology could revolutionize the way para- and quadriplegics live their lives. According to Nicolelis, if and when a brain-controlled exoskeleton becomes commonplace, spinal cord injuries will be a different animal altogether. Doctors would theoretically use this kind of technology to treat patients immediately after a spinal cord lesion, so that living in a wheelchair could be a thing of the past.

Though this all sounds a little futuristic, the end-date for this project is oddly close. "We are working with the Brazilian government, who is helping fund the project," Nicolelis says. "At the 2014 soccer World Cup celebration we hope to have a Brazilian teenager with quadriplegia walk out and make the opening kick."

While the suit for the kick-off may be a prototype, the technology that could be used in clinical practice won't be much further off, say the researchers, who project it will be available to patients within the next decade. Nicolelis assures us that the research is living up to its promises. "Since this publication," he says, "we have shown that it's possible to execute even more complex tasks with the brain-machine-brain interface. The next papers we have coming out will be even more stunning."

The idea that this type of neuro-technological solution could be available to patients within our lifetimes is exciting. But time will tell whether it is a thing for marvel or Marvel.

Image: Pedro Talens Masip/Shutterstock.