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Biological computer born

Wednesday, June 2, 1999 Published at 13:12 GMT 14:12 UK - A computer made
of neurons taken from leeches has been created by US scientists. At the
moment, the device can perform simple sums - the team calls the novel
calculator the "leech-ulator".

But their aim is to devise a new generation of fast and flexible computers
that can work out for themselves how to solve a problem, rather than having
to be told exactly what to do.

Professor Bill Ditto, at the Georgia Institute of Technology, is leading
the project and says he is amazed that today's computers are still so dumb.

"Ordinary computers need absolutely correct information every time to come
to the right answer," he says. "We hope a biological computer will come to
the correct answer based on partial information, by filling in the gaps
itself."

The device the team has built can "think for itself" because the leech
neurons are able to form their own connections from one to another. Normal
silicon computers only make the connections they are told to by the
programmer.

This flexibility means the biological computer works out it own way of
solving the problem. "With the neurons, we only have to direct them towards
the answer and they get it themselves," says Professor Ditto.

This approach to computing is particularly suited to pattern recognition
tasks like reading handwriting, which would take enormous amounts of power
to do well on a conventional computer.

The neurons are harnessed in a petri dish by inserting micro-electrodes
into them. Each neuron has its own electrical activity and responds in its
own way to an electrical stimulus.

These features can be used to make each neuron represent a number.
Calculations are then performed by linking up the individual neurons.

Leech neurons are used because they have been extensively studied and are
well understood.

Though much simpler, the neuron computer works in a similar way to the
human brain. Professor Ditto says a robot brain is his long-term aim,
noting that conventional supercomputers are far too big for a robot to
carry around.

"We want to be able to integrate robotics, electronics and these type of
computers so that we can create more sentient robots," he says.

However, in the immediate future, the team from Georgia Tech and Emory
University are working on enabling their computer to do multiplication.

The biological computer is featured on BBC One's Tomorrow's World at 1930
BST on Wednesday 2 June 1999.


BBC News Online: Sci/Tech
http://news.bbc.co.uk/low/english/sci/tech/newsid_358000/358822.stm

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