[extropy-chat] UF scientist: 'Brain' in a dish acts as autopilot, living computer

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UF scientist: 'Brain' in a dish acts as autopilot, living computer

http://www.eurekalert.org/pub_releases/2004-10/uof-us102104.php

GAINESVILLE, Fla. --- A University of Florida scientist has grown a
living "brain" that can fly a simulated plane, giving scientists a
novel way to observe how brain cells function as a network.

The "brain" -- a collection of 25,000 living neurons, or nerve cells,
taken from a rat's brain and cultured inside a glass dish -- gives
scientists a unique real-time window into the brain at the cellular
level. By watching the brain cells interact, scientists hope to
understand what causes neural disorders such as epilepsy and to
determine noninvasive ways to intervene. As living computers, they may
someday be used to fly small unmanned airplanes or handle tasks that
are dangerous for humans, such as search-and-rescue missions or bomb
damage assessments.

"We're interested in studying how brains compute," said Thomas
DeMarse, the UF professor of biomedical engineering who designed the
study. "If you think about your brain, and learning and the memory
process, I can ask you questions about when you were 5 years old and
you can retrieve information. That's a tremendous capacity for memory.
In fact, you perform fairly simple tasks that you would think a
computer would easily be able to accomplish, but in fact it can't."

While computers are very fast at processing some kinds of information,
they can't approach the flexibility of the human brain, DeMarse said.
In particular, brains can easily make certain kinds of computations –
such as recognizing an unfamiliar piece of furniture as a table or a
lamp – that are very difficult to program into today's computers.

"If we can extract the rules of how these neural networks are doing
computations like pattern recognition, we can apply that to create
novel computing systems," he said.

DeMarse experimental "brain" interacts with an F-22 fighter jet flight
simulator through a specially designed plate called a multi-electrode
array and a common desktop computer.

"It's essentially a dish with 60 electrodes arranged in a grid at the
bottom," DeMarse said. "Over that we put the living cortical neurons
from rats, which rapidly begin to reconnect themselves, forming a
living neural network – a brain."

The brain and the simulator establish a two-way connection, similar to
how neurons receive and interpret signals from each other to control
our bodies. By observing how the nerve cells interact with the
simulator, scientists can decode how a neural network establishes
connections and begins to compute, DeMarse said.

When DeMarse first puts the neurons in the dish, they look like little
more than grains of sand sprinkled in water. However, individual
neurons soon begin to extend microscopic lines toward each other,
making connections that represent neural processes. "You see one
extend a process, pull it back, extend it out – and it may do that a
couple of times, just sampling who's next to it, until over time the
connectivity starts to establish itself," he said. "(The brain is)
getting its network to the point where it's a live computation
device."

To control the simulated aircraft, the neurons first receive
information from the computer about flight conditions: whether the
plane is flying straight and level or is tilted to the left or to the
right. The neurons then analyze the data and respond by sending
signals to the plane's controls. Those signals alter the flight path
and new information is sent to the neurons, creating a feedback
system.

"Initially when we hook up this brain to a flight simulator, it
doesn't know how to control the aircraft," DeMarse said. "So you hook
it up and the aircraft simply drifts randomly. And as the data comes
in, it slowly modifies the (neural) network so over time, the network
gradually learns to fly the aircraft."

Although the brain currently is able to control the pitch and roll of
the simulated aircraft in weather conditions ranging from blue skies
to stormy, hurricane-force winds, the underlying goal is a more
fundamental understanding of how neurons interact as a network,
DeMarse said.

"There's a lot of data out there that will tell you that the
computation that's going on here isn't based on just one neuron. The
computational property is actually an emergent property of hundreds or
thousands of neurons cooperating to produce the amazing processing
power of the brain."

With Jose Principe, a UF distinguished professor of electrical
engineering and director of UF's Computational NeuroEngineering
Laboratory, DeMarse has a $500,000 National Science Foundation grant
to create a mathematical model that reproduces how the neurons
compute.

These living neural networks are being used to pursue a variety of
engineering and neurobiology research goals, said Steven Potter, an
assistant professor in the Georgia Tech/Emory Department of Biomedical
Engineering who uses cultured brain cells to study learning and
memory. DeMarse was a postdoctoral researcher in Potter's laboratory
at Georgia Tech before he arrived at UF.

"A lot of people have been interested in what changes in the brains of
animals and people when they are learning things," Potter said. "We're
interested in getting down into the network and cellular mechanisms,
which is hard to do in living animals. And the engineering goal would
be to get ideas from this system about how brains compute and process
information."

Though the "brain" can successfully control a flight simulation
program, more elaborate applications are a long way off, DeMarse said.
"We're just starting out. But using this model will help us understand
the crucial bit of information between inputs and the stuff that comes
out," he said. "And you can imagine the more you learn about that, the
more you can harness the computation of these neurons into a wide
range of applications."