From Scientific American:
In 1979 Francis Crick, famed co-discoverer of DNA’s structure, published an article in Scientific American that set out a wish list of techniques needed to fundamentally improve understanding of the way the brain processes information. High on his wish list was a method of gaining control over specific classes of neurons while, he wrote, “leaving the others more or less unaltered.” Over the past few years Crick’s vision for targeting neurons has begun to materialize thanks to a sophisticated combination of fiber optics and genetic engineering. The advent of what is known as optogenetics has even captured popular attention because of its ability to alter animal behavior—one research group demonstrated how light piped into a mouse’s brain can drive it to turn endlessly in circles. Such feats have inspired much public comment, including a joke made by comedian Jay Leno in 2006 about the prospect for an optogenetically controlled fly pestering George W. Bush.
Controlling a subordinate or a spouse with a souped-up laser pointer may be essential for science-fiction dystopia and late-night humor, but in reality optogenetics has emerged as the most important new technology for providing insight into the numbingly complex circuitry of the mammalian brain. It has already furnished clues as to how neural miswiring underlies neurological and mental disorders, including Parkinson’s disease and schizophrenia.