Neurotechnology: Growing a Brain in Switzerland
A network of artificial nerves is growing in a Swiss supercomputer -- meant to simulate a natural brain, cell-for-cell. The researchers at work on "Blue Brain" promise new insights into the sources of human consciousness.
The machine is beautiful as it wakes up -- nerve cells flicker on the screen in soft pastel tones, electrical charges flash through a maze of synapses. The brain, just after being switched on, seems a little sleepy, but gentle bursts of current bring it fully to life.
This unprecedented piece of hardware consists of about 10,000 computer chips that act like real nerve cells. To simulate a natural brain, part of the cerebral cortex of young rats was painstakingly replicated in the computer, cell by cell, together with the branched tree-like structure of the synapses.
The simulation was created at the Technical University in Lausanne, Switzerland, where 35 researchers participate in maintaining this artificial brain. It runs on one of the world's most powerful supercomputers, but soon even that computer will be too small. The goal is to build a much bigger electronic thinking machine -- one that would ultimately replicate the human brain.
A project this ambitious would have been ridiculed a few years ago. "Today we have the computers we need," says biologist Henry Markram, 44, the project's director. "And we know enough to begin."
Markram knows about the problems his group can look forward to. "But if we don't build the brain," he says, "we'll never understand how it works." In fact, there have been tremendous advances in brain research for years; but answers to the big questions are as elusive as ever. How does consciousness develop within the electric orchestra of cells? How exactly does a spark of intellect ignite from the interplay among genes, proteins and messenger substances?
Though the first artificial brain may seem simple, it will be a useful model. Brain researchers can use it to reproduce functions from the real organ and test their theories. As they build in new processes, the model grows ever more detailed -- a sort of wiki project of the mind. It also offers an important advantage over a natural brain, since it lets researchers monitor each and every (simulated) mental activity in the machine.
But -- has there been mental activity?
The newborn "Blue Brain" surprised the designers with its willfulness from the very first day. It had hardly been fed electrical impulses before strange patterns began to appear on the screen with the lightning-like flashes produced by cells that scientists recognize from actual thought processes. Groups of neurons started becoming attuned to one another until they were firing in rhythm. "It happened entirely on its own," says Markram. "Spontaneously."
Building the electronic rat brain
Ten thousand artificial nerve cells have been interwoven in Lausanne, and the researchers aim to increase the number to one million within the next year. Which doesn't mean they're satisfied: The work is scheduled right now to last beyond 2015. By then, unless the project proves too ambitious, Markram and his team hope to be ready for their primary goal: a computer model of an entire human brain -- right now almost a sheer flight of fancy, given the 100 billion cells they would have to engineer.
Graphic: the mind under construction
Perhaps the only ones who could have known are the scores of rats that carry on a shadow-like existence in this supercomputer. Researchers opened thousands of rat skulls over the years, removed their brains, and cut them into thin slices, which they kept alive. Then they directed tiny sensors at the individual neurons. They listened to the cells firing neurons, and intercepted the responses coming from the adjacent cells.
The brain slices were exposed to a variety of electrical impulses. The impulses reflected the stimuli that may have been received by the laboratory rats' brains when the animals smelled cheese or were startled by a shape. The cells reacted -- just as they did when the rats were still alive -- by sending electrical charges through the neuroplexus. The researchers' measuring devices recorded all signals until the brain slices expired.
In the end, the researchers at Markram's lab collected the entire repertoire of behavior of hundreds of types of cells in every conceivable situation in a rat's life -- stored in endless tables. This vast stockpile of data let the researchers start building their digital doppelgänger.
- Part 1: Growing a Brain in Switzerland
- Part 2: The price of uncompromising realism
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