[tt] For Future of Mind Control, Robot-Monkey Trials Are Just a Start

[Eugen Leitl]

http://www.popularmechanics.com/science/research/4272246.html

By Erik Sofge

Published on: July 7, 2008

The Force, it appears, may be with us sooner than expected. A study in the
journal Nature this spring all but confirmed the latest evolution in the
hard-charging, heady field of cybernetics: Monkeys can control machines with
their brains. In the experiment, conducted by neuroscientists at the
University of Pittsburgh and Carnegie Mellon University, a pair of macaque
monkeys with electrodes implanted in their brains were able to quickly learn
how to operate a robot arm as though it were their own, successfully fee ding
themselves more than half the time. Aside from building a fleet of
potentially potbellied test subjects, however, could this apparent
breakthrough bring mind control to human prosthetics anytime soon? Or could
it mean even more?

On the research track of brain-computer interfaces—direct neural connections
that allow brain signals to operate a device—the robo-joystick monkeys look
awfully familiar. That’s because Pitt released similar results in 2005, with
a different kind of robotic arm used to grasp and retrieve food. And as far
back as 2000, electrode-implanted monkeys at Duke University moved a robot
arm—again, to reach for food—with their minds. Scientists at Duke ran similar
experiments in 2003 and, this past January, showed off a rig that let an owl
monkey on a treadmill control the walking movements of a 200-pound humanoid
robot in Japan.

As interesting (if repetitive) as each of these incremental achievements are,
the endgame for mind-machine interfaces is nothing short of astonishing. In
the years to come, this technology could lead to prosthetics that react
perfectly to a user’s thoughts, or devices that move in ways we never
imagined, responding to mental commands faster than our own bodies can. The
future of hyperspeed brain control outside of the lab may come littered with
more pratfall than promise—even the field’s leading neuroscientist offered
plenty of caveats and insisted, like his peers, that one or two major
breakthroughs in other fields are still needed to open up the devices to
everyone. But if the recent run of mind-bending success in this field is any
indication, the big breaks can come faster than expected.

Building Postprosthetic Cybernetics

For Miguel Nicolelis, a professor of neuroscience at Duke University Medical
Center, the backbone of mind-machine interfaces is the ability to analyze
neural activity. Sure, the system demonstrated at Pitt in May accessed
information from 100 neurons at once. But Nicolelis’s lab has managed five
times that amount, with data coming from up to 10 different brain structures.
“We’re able to look at brain dynamics on a scale that no one else has been
able to,” he says. “You’re transferring information into motion. When more
neurons are recorded, it allows you to extract many more parameters from the
brain, to look for more elaborate output.” The result is more fine-tuned
movement for devices—and more data recorded from a given subject—to help
researchers analyze the relationship between brain signals and physical
activity.

More neuron data paths could also improve the capacity of monkeys (and, some
day, humans) to not only send outgoing commands to a device, but also process
incoming signals. Nicolelis and his team have created what he calls
“brain-machine-brain” interfaces wherein monkeys respond to feedback from a
device. In some cases, the test subjects show surprising amounts of so-called
“brain plasticity”—the mind’s adaptability to new kinds of movements.
According to Nicolelis, that’s more promising and less abstract than it might
sound.

Current prosthetics, even devices as advanced as Johns Hopkins superstar
Proto 2, rely heavily on brain plasticity. A user might train himself to
close a prosthetic pincer by shrugging his shoulder, and his brain adapts,
with the shrug-grasp motion eventually becoming second nature. Proto 2 can
respond to signals from residual nerves on the surface of a limb or in the
user’s chest, but the feedback it provides is something of a sleight of hand
(no pun intended). Without a direct connection to the brain, the best it can
do is simulate the sensation of pressure or heat wherever the electrodes come
into contact with the body. So the surface of an amputated limb might seem
hot, or the embedded electrodes in a subject’s chest might feel a poke. But
it’s up to brain plasticity to associate that sensation with the warmth of an
open fire or the tactile feedback of a tennis ball.

With a physical neural connection, Nicolelis believes that brain plasticity
can be achieved quickly and with greater precision than current prosthetic
control systems. “When you link the brain to a device, it could allow scaling
in force and time—things that, today, your body can’t do,” he says. So the
brain would not only respond to data from sensors in the bionic limb, but
would account for unfamiliar amounts of speed and force. For sci-fi fans, the
implications don’t need spelling out: prosthetics that are faster and
stronger than normal limbs, with roughly the same level of control as their
flesh-and-blood predecessors. Without a closed neural loop, it would
theoretically take much longer to become accustomed to an enhanced arm and
fold it into normal brain activity. The key to cybernetic devices that
restore function and increase it rests with the humble electrodes currently
popping out of monkey skulls—and the loads of data therein. 

Rethinking the Speed of Your Brain

In the deeper theoretical territory of brain-computer interfaces—goals that
could be rendered moot without big leaps in the next few years—the
experiments begin to intersect with philosophy. As Nicolelis points out, the
plasticity provided by a closed loop could apply to entirely new movements
that aren’t a part of our standard physical repertoire. “For the foreseeable
future, the main benefit is for rehabilitation,” he says. “But the research
is showing that the brain can act independently of the body. One day, you
could be sitting in an office and controlling a device from across the
room—or in another building. And it’s not just flicking a switch. It could be
a nanotool that’s moving through a tiny environment, and you can control it
and see what it’s seeing.”

That kind of extension could lead to new spectrums of scale and force, not to
mention new kinds of sensory input altogether. Instead of merely imagining
that you’re grasping a nanotool with virtual fingers, you could learn to
pilot it like a miniscule spaceship—only with your mind. And if that device
had any sensors, you might be able to process the data as though it were a
tiny camera. This is not the same thing as imagining that your legs are
moving in order to control a walking robot half a world away, as in this
year’s experiment at Duke. A two-way mind-machine interface with a remote
device, after all, might begin to redefine how we perceive and interact with
our environment.

Difficult as space would be to perceive at such a point, one very real result
of Nicolelis’s research could throw time into question too. The main purpose
of the walking robot experiment was to demonstrate just how precisely brain
activity could be translated, but it produced another interesting result: It
actually took less time for the brain signal to travel from the monkey in
North Carolina to the robot in Japan than it took to go from the primate’s
brain to its own muscles. At any given moment, then, the bot was receiving
the command to walk before the monkey’s body did.

In a one-way mind-machine interface, being able to trigger movements
essentially faster than the speed of thought could make for some seriously
spastic hijinks. A prosthetic arm might slap a glass off of a table the
instant you realize you’re thirsty, or a remote-operated humanoid robot could
simply thrash around in the kinetic equivalent of satellite lag during a
television interview. But thanks to brain plasticity, Nicolelis believes that
humans with a two-way interface would learn to harness that narrowed gap
between thought and movement. Here, however, the closely watched researcher
refused to speculate about potential applications, saying only, “With certain
things, being quicker can be fundamental—the use of a particular tool, or a
particular medical procedure.”

Reinventing the Electrode for Human Applications 

The bad news, of course, is that as endless as these possibilities may seem,
they remain quite far-off.  Eventually, researchers will shift their focus
toward translating the brain activity of monkeys to the similar (but not too
similar) neurological workings of human beings. Relatively speaking, that
leap shouldn’t take too long. After all, it’s why most scientists in this
field use specific species of monkeys whose brains and brain activity share
certain features with those of humans. It will also take years to develop a
truly functional knowledge of how the primate brain turns thought into motion
and nerve signals into sensation.

But the biggest obstacle of all could be the interface itself. Only with the
promise of restoring bodily functions would most human test subjects agree to
have electrodes permanently implanted in their heads. Barring some bizarre
shift in values (and a corresponding spike in unethical surgeons), the leap
from rehabilitation-oriented interfaces to elective ones is nearly impossible
to fathom. Reaching a wider audience would require a revolution in
noninvasive interfaces, such as electrode-studded caps. “The problem is you
can’t get the same kind of resolution. You only get binary data,” says
Nicolelis. “To reconstruct true trajectories would require new
technology—something that might allow you to go through bone without opening
it, some optical method we haven’t seen yet.”

And that would amount to a breakthrough in physics, as there is zero
indication that any such transmission method is imminent. Until someone
reinvents the electrode, the most advanced brain-controlled devices will be
reserved for the disabled. So far, the majority of mind-machine interface
experiments involving humans has involved remote controls and computers.
Nicolelis is convinced, however, that his research will make it out of the
lab, into the hospital and into the lives of those who need it most. “We are
getting close to the moment when we can do something very relevant with
rehabilitation,” he says. “But it has to start with invasive neural
interfaces. That’s the first step.”