本帖最后由 domudomu 于 2010-1-27 22:30 编辑
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.” （克里克是发现DNA模型人之一，发的文章增加了人们了解大脑是如何传递信息的，通过神经元）
Over the past few years Crick’s vision for targeting neurons has begun to materialize（成为现实化） thanks to a sophisticated combination of fiber optics and genetic engineering. The advent（出现降临) of what is known as opto genetics has even captured popular attention because of its ability to alter animal behavior—one research group demonstrated how light piped(传递传输） into a mouse’s brain can drive it to turn endlessly in circles. Such feats（功绩） have inspired much public comment, including a joke made by comedian Jay Leno in 2006 about the prospect for an opto genetically controlled fly pestering（使烦恼，纠缠） George W. Bush. （基因工程和纤维光的结合形成光基因，从而改变动物行为）
Controlling a subordinate or a spouse with a souped-up（提高效率） laser pointer may be essential for science-fiction dystopia（糟糕的，非理想化的处境） and late-night humor, but in reality optogenetics has emerged as the most important new technology for providing insight into the numbingly（麻木失去知觉的） complex circuitry of the mammalian brain. It has already furnished clues as to how neural miswiring（错接） underlies neurological and mental disorders, including Parkinson’s disease and schizophrenia（精神分裂症）. 光学基因先其实已经是非常重要的技术，对于哺乳动物大脑神经，和里面是怎么混乱的）
A seminal（对以后有重大影响的） event that sparked widespread neuroscience interest came in 2005, when Karl Deisseroth and his colleagues at Stanford University and at the Max Planck Institute for Biophysics in Frankfurt demonstrated how a virus could be used to deliver a light-sensitive gene called channelrhodopsin-2 into specific sets of mammalian neurons. Once equipped with the gene (taken from pond algae（海藻）), the neurons fired when exposed to light pulses. A box on Crick’s list could be checked off: this experiment and ones that were soon to follow showed how it would be possible to trigger（引起） or extinguish selected neurons, and not their neighbors, in just a few milliseconds, the speed at which they normally fire. Hundreds of laboratories（真空吸引分娩） worldwide have since adopted Deisseroth’s technique. （用病毒来传送感光基因到指定的神经，并确认作用到特定神经）
A 38-year-old psychiatrist by training who still sees patients once a week, Deisseroth entered the field of bioengineering because of his frustration over the inadequate tools available to research and treat mental illness and neurodegenerative（神经组织退化） disorders. “I have conducted many brain-stimulation treatments in psychiatry that suffered greatly from a lack of precision. You can stimulate certain cells that you want to target, but you also stimulate all of the wrong cells as well,” he says. Instead of just observing the effects from a drug or an implanted electrode（电极）, optogenetics brings researchers closer to the fundamental causes of a behavior. （神经科学家，由于他在自己医学领域总是会在选择到正确基因的同时选择到错误基因，从事光电基因专业）
Since 2005 Deisseroth’s laboratory—at times in collaboration with leading neuroscience groups—has assembled a powerful tool kit based on channelrhodopsin-2 and other so-called opsins（视蛋白）. By adjusting the opening or closing of channels in cell membranes, opsins can switch neurons on or turn them off. Molecular legerdemain（手法，戏法） can also manipulate（熟练操作） just a subset of one type of neuron or control a circuit between groups of selected neurons in, say, the limbic（边缘） system and others in the cortex（皮层）. Deisseroth has also refined methods for delivering the opsin genes, typically by inserting into a virus both opsin genes and DNA to turn on those genes. （通过视蛋白来调控基因）
To activate the opsins, Deisseroth’s lab has attached laser diodes（二极管） to tiny fiber-optic cables that reach the brain’s innermost structures. Along with the optical fibers, electrodes are implanted that record when neurons fire. “In the past year what’s happened is that these techniques have gone from being something interesting and useful in limited applications to something generalizable to any cell or question in biology,” Deisseroth says. （为了激活视蛋白，给深处视觉神经以刺激）
Most compelling, however, are experiments that have demonstrated te relevance of optogenetics to both basic science and medicine. At the Society for Neuroscience meeting in Chicago last October, Michael Häusser of University College London reported on an optogenetics experiment that showed how 100 neurons could trigger a memory stored in a much larger ensemble of about 100,000 neurons, suggesting how the technique may be used to understand memory formation. （做一些与电光基因相关的实验，100个神经元可以引起一个尝过十万的储存）
Last spring Deisseroth’s group published an optogenetics study that helped to elucidate（说明，阐明） the workings of deep-brain stimulation, which uses electrodes implanted deep in the brain to alleviate the abnormal movements of Parkinson’s disease. The experiment called into question the leading theory of how the technology works—activation of an area called the subthalamic（丘脑下的） nucleus. Instead the electrodes appear to exert their effects on nerve fibers that reach the subthalamic nucleus from the motor cortex and perhaps other areas. The finding has already led to a better understanding of how to deploy（有效利用） deep-brain electrodes. Given its fine-tuned（微调） specificity, optoelectronics might eventually replace deep-brain stimulation. （用电极移植到脑来减轻帕金森综合症的不正常行为，光电基因，最后可能会代替深脑刺激）
Although optogenetic control of human behavior may be years away, Deisseroth comments that the longer-range（长程） implications of the technology must be considered: “I’m not writing ethics papers, but I think about these issues every day, what it might mean to gain understanding and control over what is a desire, what is a need, what is hope.” comments Cool, this is the second biology-related issue read by me carefully this night. I can actully understand most of the meanings and works. And what really touched me is the last paragraph. However, I can feel how hard the scientific work is and how great every scientist is. "What it might mean to gain understanding and control over what is a desire, what is a need, what is hope." Many people will get Parkinson's disease when they get old. Luckliy the researchers are now trying hard to solve this big issue. And it seems that the Parkinson's disease is getting easier to be controled than cancer. And, I fully believe these scientists, their contribution is beyond anything. I also hope that one day, people will never be bothered with various diseases and to live a happy life. To my grandpa: May you a good health and long life！ I will stand by you forever. | 
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楼主: prettywraith
发表于 2010-1-22 10:39:20
发表于 2010-1-28 22:57:43
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