Interesting article. Numerous implications for this research/breakthrough, which will be interpreted a number of ways depending on your leanings: mainstream [potential cure for Parkinson's!], Futurist [one step closer to merging man and machine!], and 'Conspiracy Theorist' [ostensibly labeled as a breakthrough to "cure" illnesses, this technology will ultimately only serve to further control the masses and their thought processes..]
http://www.wired.com/magazine/2009/10/mf_optigenetics
Some excerpts:
"Now, using light to make neurons fire wouldn’t be a huge deal; electricity could do that. But the exciting part was that a gene could be designed to affect only specific kinds of neurons. Scientists can mark a gene with a 'promoter' — a cell-specific piece of DNA that controls whether a gene is used.
Here’s what they do: Insert the gene (plus promoter) into a group of viral particles and inject them into the brain. The viruses infect a cubic millimeter or two of tissue. That is to say, they insert the new gene into every neuron in that area, indiscriminately. But because of the promoter, the gene will only turn on in one type of neuron. All the other neurons will ignore it. Imagine you wanted only the lefty in an outfield to catch. How would you do that? Distribute left-handed gloves to all the players. The righties would just stand there, fidgeting and calling their agents. The lefty would spring into action. Just as the lefty is 'tagged' by his ability to use the glove, a neuron is “tagged” by its ability to use the gene. Bye-bye side effects: Researchers would be able to stimulate one kind of neuron at a time."
...
"...they now had an On switch for neurons. But in the brain, it’s as important to inhibit neurons as it is to make them fire. As with computers, 0 is as crucial as 1; they needed an Off switch, too. When Boyden finished his PhD, he took an appointment at MIT and began hunting for it. He found there was a bacterial gene, halorhodopsin, that had properties suggesting it could do the opposite of channelrhodopsin. In 2006, Boyden inserted halorhodopsin into neurons and exposed them to yellow light. They stopped firing. Beautiful."
...
"Over at Stanford, Deisseroth’s team was making the same discovery, and soon they were stopping worms in their tracks with yellow light. Other labs were already making flies leap into the air when exposed to blue light. And on The Tonight Show, Jay Leno had even joked about the technology with a clip in which he pretended to steer a 'remote control' fly into George W. Bush’s mouth. The research was mushrooming, and dozens of labs were calling Deisseroth to ask for the genes. The new field was dubbed optogenetics: optical stimulation plus genetic engineering.
But neurons in petri dishes and in bugs were comparatively simple. Would optogenetics work in the staggeringly complex tangle of a mammalian brain? And could it be used to cure real brain illnesses?"
...
"Over at MIT, Boyden was asking the obvious question: Would this work on people? But imagine saying to a patient, 'We’re going to genetically alter your brain by injecting it with viruses that carry genes taken from pond scum, and then we’re going to insert light sources into your skull.' He was going to need some persuasive safety data first."
...
"...the next step was creating a device that didn’t require threading cables through the skull. One of Deisseroth’s colleagues designed a paddle about one-third the length of a popsicle stick. It has four LEDs: two blue ones to make neurons fire and two yellow ones to stop them. Attached to the paddle is a little box that provides power and instructions. The paddle is implanted on the surface of the brain, on top of the motor control area. The lights are bright enough to illuminate a fairly large volume of tissue, so the placement doesn’t have to be exact. The light-sensitizing genes are injected into the affected tissue beforehand. It’s a far easier surgery than deep brain electrical stimulation, and, if it works, a far more precise treatment. Researchers at Stanford are currently testing the device on primates. If all goes well, they will seek FDA approval for experiments in humans."
