The $1.3B Quest to Build a Supercomputer Replica of a Human Brain
Even by the standards of the TED conference, Henry Markram’s 2009 TEDGlobal talk was a mind-bender. He took the stage of the Oxford Playhouse, clad in the requisite dress shirt and blue jeans, and announced a plan that—if it panned out—would deliver a fully sentient hologram within a decade. He dedicated himself to wiping out all mental disorders and creating a self-aware artificial intelligence. And the South African–born neuroscientist pronounced that he would accomplish all this through an insanely ambitious attempt to build a complete model of a human brain—from synapses to hemispheres—and simulate it on a supercomputer. Markram was proposing a project that has bedeviled AI researchers for decades, that most had presumed was impossible. He wanted to build a working mind from the ground up.
In the four years since Markram’s speech, he hasn’t backed off a nanometer. The self-assured scientist claims that the only thing preventing scientists from understanding the human brain in its entirety—from the molecular level all the way to the mystery of consciousness—is a lack of ambition. If only neuroscience would follow his lead, he insists, his Human Brain Project could simulate the functions of all 86 billion neurons in the human brain, and the 100 trillion connections that link them. And once that’s done, once you’ve built a plug-and-play brain, anything is possible. You could take it apart to figure out the causes of brain diseases. You could rig it to robotics and develop a whole new range of intelligent technologies. You could strap on a pair of virtual reality glasses and experience a brain other than your own.
The way Markram sees it, technology has finally caught up with the dream of AI: Computers are finally growing sophisticated enough to tackle the massive data problem that is the human brain. But not everyone is so optimistic. “There are too many things we don’t yet know,” says Caltech professor Christof Koch, chief scientific officer at one of neuroscience’s biggest data producers, the Allen Institute for Brain Science in Seattle. “The roundworm has exactly 302 neurons, and we still have no frigging idea how this animal works.” Yet over the past couple of decades, Markram’s sheer persistence has garnered the respect of people like Nobel Prize–winning neuroscientist Torsten Wiesel and Sun Microsystems cofounder Andy Bechtolsheim. He has impressed leading figures in biology, neuroscience, and computing, who believe his initiative is important even if they consider some of his ultimate goals unrealistic.
Markram has earned that support on the strength of his work at the Swiss Federal Institute of Technology in Lausanne, where he and a group of 15 postdocs have been taking a first stab at realizing his grand vision—simulating the behavior of a million-neuron portion of the rat neocortex. They’ve broken new ground on everything from the expression of individual rat genes to the organizing principles of the animal’s brain. And the team has not only published some of that data in peer-reviewed journals but also integrated it into a cohesive model so it can be simulated on an IBM Blue Gene supercomputer.
The big question is whether these methods can scale. There’s no guarantee that Markram will be able to build out the rest of the rat brain, let alone the vastly more complex human brain. And if he can, nobody knows whether even the most faithful model will behave like a real brain—that if you build it, it will think. For all his bravado, Markram can’t answer that question. “But the only way you can find out is by building it,” he says, “and just building a brain is an incredible biological discovery process.” This is too big a job for just one lab, so Markram envisions an estimated 6,000 researchers around the world funneling data into his model. His role will be that of prophet, the sort of futurist who presents worthy goals too speculative for most scientists to countenance and then backs them up with a master plan that makes the nearly impossible appear perfectly plausible. Neuroscientists can spend a whole career on a single cell or molecule. Markram will grant them the opportunity and encouragement to band together and pursue the big questions.
And now Markram has funding almost as outsized as his ideas. On January 28, 2013, the European Commission—the governing body of the European Union—awarded him 1 billion euros ($1.3 billion). For decades, neuroscientists and computer scientists have debated whether a computer brain could ever be endowed with the intelligence of a human. It’s not a hypothetical debate anymore. Markram is building it. Will he replicate consciousness? The EU has bet $1.3 billion on it.
Ancient Egyptian surgeons believed that the brain was the “marrow of the skull” (in the graphic wording of a 3,500-year-old papyrus). About 1,500 years later, Aristotle decreed that the brain was a radiator to cool the heart’s “heat and seething.” While neuroscience has come a long way since then, the amount that we know about the brain is still minuscule compared to what we don’t know.
Over the past century, brain research has made tremendous strides, but it’s all atomized and highly specific—there’s still no unified theory that explains the whole. We know that the brain is electric, an intricately connected network, and that electrical signals are modulated by chemicals. In sufficient quantity, certain combinations of chemicals (called neurotransmitters) cause a neuron to fire an electrical signal down a long pathway called an axon. At the end of the axon is a synapse, a meeting point with another neuron. The electrical spike causes neurotransmitters to be released at the synapse, where they attach to receptors in the neighboring neuron, altering its voltage by opening or closing ion channels. At the simplest level, comparisons to a computer are helpful. The synapses are roughly equivalent to the logic gates in a circuit, and axons are the wires. The combination of inputs determines an output. Memories are stored by altering the wiring. Behavior is correlated with the pattern of firing.
Yet when scientists study these systems more closely, such reductionism looks nearly as rudimentary as the Egyptian notions about skull marrow. There are dozens of different neurotransmitters (dopamine and serotonin, to name two) plus as many neuroreceptors to receive them. There are more than 350 types of ion channel, the synaptic plumbing that determines whether a neuron will fire. At its most fine-grained, at the level of molecular biology, neuroscience attempts to describe and predict the effect of neurotransmitters one ion channel at a time. At the opposite end of the scale is functional magnetic resonance imaging, the favorite tool of behavioral neuroscience. Scans can roughly track which parts of the brain are active while watching a ball game or having an orgasm, albeit only by monitoring blood flow through the gray matter: the brain again viewed as a radiator.
Two large efforts—the Allen Brain Atlas and the National Institutes of Health-funded Human Connectome Project—are working at levels in between these two extremes, attempting to get closer to that unified theory that explains the whole. The Allen Brain Atlas is mapping the correlation between specific genes and specific structures and regions in both human and mouse brains. The Human Connectome Project is using noninvasive imaging techniques that show where wires are bundled and how those bundles are connected in human brains.
To add to the brain-mapping mix, President Obama in April announced the launch of an initiative called Brain (commonly referred to as the Brain Activity Map), which he hopes Congress will make possible with a $3 billion NIH budget. (To start, Obama is pledging $100 million of his 2014 budget.) Unlike the static Human Connectome Project, the proposed Brain Activity Map would show circuits firing in real time. At present this is feasible, writes Brain Activity Map participant Ralph Greenspan, “in the little fruit fly Drosophila.”
Even scaled up to human dimensions, such a map would chart only a web of activity, leaving out much of what is known of brain function at a molecular and functional level. For Markram, the American plan is just grist for his billion-euro mill. “The Brain Activity Map and other projects are focused on generating more data,” he writes. “The Human Brain Project is about data integration.” In other words, from his exalted perspective, the NIH and President Obama are just a bunch of postdocs ready to work for him.