Out of the Blue. A biologically accurate brain built out of a supercomputer
A computer simulation of the upper layer of a rat brain
neocortical column. Here neurons light up in a "global excitatory
state" of blues and yellows.In the basement of a university in Lausanne, Switzerland sit
four black boxes, each about the size of a refrigerator, and filled
with 2,000 IBM microchips stacked in repeating rows. Together they form
the processing core of a machine that can handle 22.8 trillion
operations per second. It contains no moving parts and is eerily
silent. When the computer is turned on, the only thing you can hear is
the continuous sigh of the massive air conditioner. This is Blue Brain.
The name of the supercomputer is literal: Each of its microchips has
been programmed to act just like a real neuron in a real brain. The
behavior of the computer replicates, with shocking precision, the
cellular events unfolding inside a mind. "This is the first model of
the brain that has been built from the bottom-up," says Henry Markram,
a neuroscientist at Ecole Polytechnique Fédérale de Lausanne (EPFL) and
the director of the Blue Brain project. "There are lots of models out
there, but this is the only one that is totally biologically accurate.
We began with the most basic facts about the brain and just worked from
there."
Before the Blue Brain project launched, Markram had likened it to
the Human Genome Project, a comparison that some found ridiculous and
others dismissed as mere self-promotion. When he launched the project
in the summer of 2005, as a joint venture with IBM, there was still no
shortage of skepticism. Scientists criticized the project as an
expensive pipedream, a blatant waste of money and talent. Neuroscience
didn't need a supercomputer, they argued; it needed more molecular
biologists. Terry Sejnowski, an eminent computational neuroscientist at
the Salk Institute, declared that Blue Brain was "bound to fail," for
the mind remained too mysterious to model. But Markram's attitude was
very different. "I wanted to model the brain because we didn't understand it," he says. "The best way to figure out how something works is to try to build it from scratch."
The
Blue Brain project is now at a crucial juncture. The first phase of the
project—"the feasibility phase"—is coming to a close. The skeptics, for
the most part, have been proven wrong. It took less than two years for
the Blue Brain supercomputer to accurately simulate a neocortical
column, which is a tiny slice of brain containing approximately 10,000
neurons, with about 30 million synaptic connections between them. "The
column has been built and it runs," Markram says. "Now we just have to
scale it up." Blue Brain scientists are confident that, at some point
in the next few years, they will be able to start simulating an entire
brain. "If we build this brain right, it will do everything," Markram
says. I ask him if that includes selfconsciousness: Is it really
possible to put a ghost into a machine? "When I say everything, I mean everything," he says, and a mischievous smile spreads across his face.
Henry Markram is tall and slim. He wears jeans and tailored
shirts. He has an aquiline nose and a lustrous mop of dirty blond hair
that he likes to run his hands through when contemplating a difficult
problem. He has a talent for speaking in eloquent soundbites, so that
the most grandiose conjectures ("In ten years, this computer will be
talking to us.") are tossed off with a casual air. If it weren't for
his bloodshot, blue eyes—"I don't sleep much," he admits—Markram could
pass for a European playboy.