Boyden hopes to treat blind people by putting the channels in their eyes. And ultimately, he wants to install these light-sensitive receptors on neurons deep in the brain as well. To manipulate those deep-brain neurons, he'll need a new kind of electrode. On my visit to his lab, Boyden showed me his newest prototype: a peculiar gadget that looks like a miniature glass pipe organ. At the base of each fiber a diode can produce an intense flash of light. Boyden envisions implanting this array into people's brains and then wirelessly programming it to produce a rapid-fire rainbow pattern of light.
In the far future, Boyden can imagine treating people with Parkinson's, depression, and other disorders with his implants. He doesn't give much thought to the possibility of people using implants to enhance their brains, the way they do now with Adderall. Brain implants certainly feed the imagination. Could people with implants see the world in ultraviolet? Could they control a jet fighter with thought alone? Could they become slaves of a computer?
Boyden has the luxury of not having to worry about those ethical matters. After all, it's one thing to open a jar and pop a pill; it's quite another to undergo brain surgery. "I think the invasive techniques won't be used for augmentation for a long time to come," he says.
And yet, as we talked, the conversation drifted to the subject of Lasik. Once there was a time when having a laser shot into your eye to fix myopia was the ophthalmological equivalent of Russian roulette. "Forty years ago it was daring," says Boyden. "Now there are clinics that do hundreds of these day in and day out."
I opened my Summit schedule to see what was next.
9:35 AM: Technical Road Map for Whole Brain Emulation.
10:00 AM: The Time Is Now: We Need Whole Brain Emulation.
This should be interesting, I thought.
If you haven't heard of it, here's a quick definition from a 2008 paper by Nick Bostrom and Anders Sandberg, two scientists at the University of Oxford: "The basic idea is to take a particular brain, scan its structure in detail and construct a software model of it so faithful to the original that, when run on appropriate hardware, it will behave in essentially the same way as the original brain."
At the Singularity Summit, Sandberg strode onto the stage, wearing a science-fair smile and a bright red tie, to explain what it would take to reach that goal. First, scientists would have to decide exactly how much detail they'd need. Would they have to track every single molecule? Would a rough approximation of all 100 billion neurons suffice? Sandberg suspected scientists would need a scan of a brain that could provide details down to a few nanometers (less than a millionth of an inch). Today researchers at Texas A&M have figured out how to take images of the brain at a resolution of just 160 nanometers, but they've scanned only a rice-grain-size piece of mouse brain in any one trial. To scan the brain tissue the scientists must stain it with color-producing chemicals, dunk it in plastic for hardening and then shave away one layer at a time. For now brain emulation is a zero-sum game.
But let's assume for the moment scientists can scan an entire human brain at nanometer scale. Researchers will then have to write software that can turn all the data into a three-dimensional model and then boot up this virtual brain. Sandberg doesn't think a computer would have to calculate the activity of the neurons atom by atom. Neurons are fairly predictable, so it's already possible to build models that behave a lot like real neurons. Mikael Djurfeldt, a scientist at Sweden's Royal Institute of Technology, and his colleagues have succeeded in modeling clusters of neurons known as cortical columns. They created a model of 22 million neurons joined together by 11 billion synapses. When their imitation neurons started to talk to each other, they behaved a lot like real cortical columns. Of course it's important to remember there are about 100 billion neurons in the human brain—several hundred times more than Djurfeldt has simulated.