Home' Technology Review : July August 2014 Contents 55
MIT TECHNOLOGY REVIEW
quently, and is somewhat dangerous.
When things don’t work, graduate stu-
dents hunt among tangles of wires for
John Donoghue, the Brown Univer-
sity neuroscientist who leads the longer-
running BrainGate study, compares
today’s brain-machine interfaces to the
first pacemakers. Those early models also
featured carts of electronics, with wires
punched through the skin into the heart.
Some were hand-cranked. “When you
don’t know what is going on, you keep
as much as possible on the outside and
as little as possible on the inside,” says
Donoghue. Today, though, pacemakers are
self-contained, powered by a long-lasting
battery, and installed in a doctor’s office.
Donoghue says brain-machine interfaces
are at the start of a similar trajectory.
For brain-controlled computers to
become a medical product, there has to
be an economic rationale, and the risks
must be offset by the reward. So far,
Scheuermann’s case has come closest to
showing that these conditions can be met.
In 2013, the Pittsburgh team reported its
work with Scheuermann in the medical
journal the Lancet. After two weeks, they
reported, she could move the robot arm in
three dimensions. Within a few months,
she could make seven movements, includ-
ing rotating Hector’s hand and moving the
thumb. At one point, she was filmed feed-
ing herself a bite of a chocolate bar, a goal
she had set for herself.
The researchers tried to show that
they were close to something practical—
helping with so-called “tasks of daily liv-
ing” that most people take for granted,
like brushing teeth. During the study,
Scheuermann’s abilities were examined
using the Action Research Arm Test, the
same kit of wooden blocks, marbles, and
cups that doctors use to evaluate hand
dexterity in people with recent injuries.
She scored 17 out of 57, or about as well
as someone with a severe stroke. Without
Hector, Scheuermann would have scored
zero. The findings made 60 Minutes.
Since the TV cameras went away,
however, some of the shortcomings of
the technology have become apparent.
At first Scheuermann kept demonstrat-
ing new abilities. “It was success, success,
success,” she says. But controlling Hector
has become harder. The reason is that
the implants, over time, stop recording.
The brain is a hostile environment for
electronics, and tiny movements of the
array may build up scar tissue as well. The
effect is well known to researchers and
has been observed hundreds of times in
animals. One by one, fewer neurons can
Scheuermann says no one told her.
“ The team said that they were expecting
loss of neuron signals at some point. I was
not, so I was surprised,” she says. She now
routinely controls the robot in only three
to five dimensions, and she has gradually
lost the ability to open and close its thumb
and fingers. Was this at all like her experi-
ence of becoming paralyzed? I asked her
the question a few days later by e-mail.
She replied in a message typed by an aide
who stays with her most days: “I was dis-
appointed that I would probably never
do better than I had already done, but
accepted it without anger or bitterness.”
The researcher who planned the Pitts-
burgh experiment is Andrew Schwartz, a
lean Minnesotan whose laboratory occu-
pies a sunlit floor dominated by three gray
metal towers of equipment that are used
to monitor monkeys in adjacent suites.
Seen on closed-circuit TVs, the scenes
from inside the experimental rooms defy
belief. On one screen, a metal wheel
repeatedly rotates, changing the position
of a bright orange handle. After each rev-
olution, an outsize robotic hand reaches
up from the edge of the screen to grab the
handle. Amid the spinning machinery, it’s
easy to miss the gray and pink face of the
rhesus monkey that is controlling all this
from a cable in its head.
The technology has its roots in the
1920s, with the discovery that neurons
convey information via electrical “spikes”
that can be recorded with a thin metal
wire, or electrode. By 1969, a researcher
named Eberhard Fetz had connected a
single neuron in a monkey’s brain to a dial
the animal could see. The monkey, he dis-
covered, learned to make the neuron fire
faster to move the dial and get a reward
of a banana-flavored pellet. Although Fetz
didn’t realize it at the time, he had created
the first brain-machine interface.
Schwartz helped extend that discovery
30 years ago when physiologists began
recording from many neurons in living
animals. They found that although the
entire motor cortex erupts in a blaze of
electrical signals when an animal moves,
a single neuron will tend to fire fastest in
connection with certain movements—say,
moving your arm left or up, or bending
the elbow—but less quickly otherwise.
Record from enough neurons and you can
get a rough idea of what motion a person
is making, or merely intending. “It’s like
a political poll, and the more neurons you
poll, the better the result,” he says.
The 192 electrodes on Scheuermann’s
two implants have recorded more than
At first it was “success, success, success,” but
Scheuermann says no one told her the implant might stop
working. Gradually, it is recording from fewer neurons. Her
control over the robot arm is weakening.
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