An ambitious project to create an accurate computer model of the brain has reached an impressive milestone. Scientists in Switzerland working with IBM researchers have shown that their computer simulation of the neocortical column, arguably the most complex part of a mammal’s brain, appears to behave like its biological counterpart. By demonstrating that their simulation is realistic, the researchers say, these results suggest that an entire mammal brain could be completely modeled within three years, and a human brain within the next decade.

“What we’re doing is reverse-engineering the brain,” says Henry Markram, codirector of the Brain Mind Institute at the Ecole Polytechnique Fédérale de Lausanne, in Switzerland, who led the work, called the Blue Brain project, which began in 2005. (See “IBM: The Computer Brain.”) By mimicking the behavior of the brain down to the individual neuron, the researchers aim to create a modeling tool that can be used by neuroscientists to run experiments, test hypotheses, and analyze the effects of drugs more efficiently than they could using real brain tissue.

The model of part of the brain was completed last year, says Markram. But now, after extensive testing comparing its behavior with results from biological experiments, he is satisfied that the simulation is accurate enough that the researchers can proceed with the rest of the brain.

“It’s amazing work,” says Thomas Serre, a computational-neuroscience researcher at MIT. “This is likely to have a tremendous impact on neuroscience.”

The project began with the initial goal of modeling the 10,000 neurons and 30 million synaptic connections that make up a rat’s neocortical column, the main building block of a mammal’s cortex. The neocortical column was chosen as a starting point because it is widely recognized as being particularly complex, with a heterogeneous structure consisting of many different types of synapse and ion channels. “There’s no point in dreaming about modeling the brain if you can’t model a small part of it,” says Markram.

The model itself is based on 15 years’ worth of experimental data on neuronal morphology, gene expression, ion channels, synaptic connectivity, and electrophysiological recordings of the neocortical columns of rats. Software tools were then developed to process this information and automatically reconstruct physiologically accurate 3-D models of neurons and their interconnections.

Connect the dots: A representation of a mammalian neocortical column, the basic building block of the cortex. The representation shows the complexity of this part of the brain, which has now been modeled using a supercomputer.
Credit: BBP/EPFL