Half fish,
half robot
Duncan Graham-Rowe
From New
Scientist magazine, 10 June 2000
One day your brain could live on
in a mechanical shell
THE advent of "cyborgs"
has been brought a step closer by the creation of a
strange hybrid creature with a mechanical body
controlled by the brain of a fish. As ghoulish as this
chimera sounds, it may one day allow people to be
fitted with prosthetic devices that are controlled
directly by their brain.
Light sensors housed
in the mechanical body feed the brain sensory
information. The brain tissue processes this
information to generate command signals which tell the
robot's motors which way to turn in response to its
environment. Steve Grand, a expert in artificial life
with Cyberlife Research in Somerset, describes the
work as "laudably perverse" and likely to
bring the world of cyborgs one step closer.
The robot possesses
only a few neurons borrowed from the sea lamprey
Petromyzon marinus, a primitive eel-like vertebrate.
Yet it still displays apparently "complex" behaviors
in response to simple light stimuli. Ferdinando
Mussa-Ivaldi of Northwestern University in Chicago and
his colleagues at the University of Illinois also in
Chicago and the University of Genoa, Italy, describe
it as an "artificial animal".
To create the
hybrid, the team extracted a lamprey's brainstem and
part of its spinal cord under total anesthetic, and
maintained it in an oxygenated and refrigerated salt
solution. The researchers then located a group of a
few very large nerve cells known as Müller cells.
These cells, which are easy to access and have been
extensively studied, are responsible for integrating
command and sensory signals directed to the motor
nerves, helping the lamprey orient itself.
Mussa-Ivaldi and his
colleagues then attached electrodes to stimulate the Müller
cells with the sorts of frequencies they would
normally receive. Other electrodes monitored the
activity at the axons, the output part of the neurons.
The robot itself is
a commercially available module called a Khepera and
couldn't look less like a lamprey. With two wheels and
a body made up of a couple of circular circuit boards
it looks more like a wired-up Oreo biscuit than a
cyborg. The researchers didn't mount the brain tissue
on the robot, but connected it by wire.
When the robot was
presented with a number of light stimuli, its lamprey
brain responded with a variety of behaviors, such as
following the light, avoiding the light and moving in
a circle.
The research was
originally intended to explore how brain cells adapt
to changing stimuli. But Mussa-Ivaldi hopes that
learning how neurons can communicate with artificial
machines will have other benefits. "We will be
able to build better prosthetic limbs and devices for
disabled people," he says.
Team member Vittorio
Sanguineti of the University of Genoa says the work
can also reveal the principles of how the brain learns
and how memory works. The work will be presented at
Artificial Life 7 in Portland, Oregon, in August.
Kevin Warwick, a
cyberneticist at Reading University, believes that it
may even one day be possible to have your brain
transferred to a robot when your body dies. It would
be extremely difficult, "but mapping the entire
brain to a robot can't be ruled out", he says.
More realistic, he says, is connecting electronic
devices such as mobile phones directly into our
brains.
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