Saturday, 23 October 2004

Today's Brain Link

From comes the title:

UF scientist: 'Brain' in a dish acts as autopilot, living computer
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
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.
Good luck on that last bit. I suspect that it's going to be not just non-trivial but actually hard - though an approximation would be fairly straightforward. has more on Laminated Mouse Brains similar research. If you don't get the reference, may I recommend The Rediscovery of Man by Dr Paul Linebarger, otherwise known as Cordwainer Smith.

From a review :
Like Heinlein, Smith built a detailed future history of the human race as a backdrop for his writing. It starts at the end of WWII and continues tens of thousands of years into the future. Smith spent much of his childhood in Asia, as the son of a diplomat, and grew up to become an expert in Asian culture and affairs, as well as politics in general and psycology in particular. Many of Smith's stories are rewrites of Chinese myths and fables, with casts of characters out of his dreamlike human universe governed by the omnipresent Instrumentality. Interestingly, even within this vast sweep of time, Smith's Instrumentality never chances upon a single alien race, despite the eventual development of various and increasingly efficient techniques of FTL travel. At a few points in "The Rediscovery of Man" Smith makes mention of the Instrumentality's preparations for possible alien encounters, but only modified and/or forgotten sub-species of humans are ever discovered. The word "dark" gets used a lot in describing Smith's future vision, but I don't believe that there is more darkness in his writing than would/will actually occur in a future interstellar civilization. Smith's personal history is one of witnessing human affairs from the viewpoint of those who are leading (or manipulating) the rest of us, and it is the appearance of this unique understanding in his writing that gives it it's edge - but perhaps also that element of darkness. But the wonderfully offbeat technology is pure imagination - such as the "laminated mouse brain" containing a guardian hologram for a young girl on an interstellar journey in the story "Think Blue, Count Two", or Old North Australia's strange and fearsome planetary defense system in "Mother Hitton's Littul Kittons"; a directed-telepathy weapon powered by the lethal hostility harvested from the minds of specially-bred psychotic weasels. One could actually hope that humanity turns out as exotic and abstract and imaginative (and as long-lasting!) as Smith's vision. If you are a scifi buff but are unfamiliar with Smith's work, there is a gaping hole in your expertise that you can now remedy with a single, chronologically-ordered volume of stories. If scifi really isn't your bag, I guarantee you still will be seduced and enchanted and transfixed by this relatively small body of work which, like the writing of Stanislaw Lem, raises speculative fiction to the level of literature.
Of course "Mother Hitton's Littul Kittons" is a bit far-fetched. A Defence systems consisting of enormous antenna arrays in the Outback bouncing signals off a nearby moon? Ridiculous.


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