From The Beam of Light That Flips a Switch That Turns on the Brain
...“If I were a fish, and somebody poked me in the side,” (in this case, with a fine glass tip), Dr. Isacoff said, “I would escape.” But when the translucent fish were strobed with violet light, the overstimulated creatures no longer detected being prodded. Blue-green light reversed the effect.
One advantage of the Berkeley approach, Dr. Isacoff said, is that it can be adapted for many types of proteins so they could be activated by light. But for the method to work, scientists must periodically douse cells with the glutamate string.
In contrast, Dr. Deisseroth’s laboratory at Stanford has followed nature’s simpler design, borrowing a light-sensitive protein instead of making a synthetic one.
In 2003, Georg Nagel, a biophysicist then at the Max Planck Institute of Biophysics in Frankfurt, and colleagues characterized channelrhodopsin-2 from green algae. This channel protein lets positive ions stream into cells when exposed to blue light. It functioned even when inserted into human kidney cells, the researchers showed.
Neuroscientists realized that this pond scum protein might be used to hot-wire a neuron with light. In 2005, Edward Boyden, then a graduate student at Stanford, Mr. Zhang and Dr. Deisseroth, joining with the German researchers, demonstrated that the idea worked. And in separate research published last spring, Mr. Zhang and Dr. Boyden, now at the Massachusetts Institute of Technology, each found a way to also silence neurons: a bacterial protein called halorhodopsin, when placed in a brain cell, can cause the cell to shut down in response to yellow light....
One advantage of the Berkeley approach, Dr. Isacoff said, is that it can be adapted for many types of proteins so they could be activated by light. But for the method to work, scientists must periodically douse cells with the glutamate string.
In contrast, Dr. Deisseroth’s laboratory at Stanford has followed nature’s simpler design, borrowing a light-sensitive protein instead of making a synthetic one.
In 2003, Georg Nagel, a biophysicist then at the Max Planck Institute of Biophysics in Frankfurt, and colleagues characterized channelrhodopsin-2 from green algae. This channel protein lets positive ions stream into cells when exposed to blue light. It functioned even when inserted into human kidney cells, the researchers showed.
Neuroscientists realized that this pond scum protein might be used to hot-wire a neuron with light. In 2005, Edward Boyden, then a graduate student at Stanford, Mr. Zhang and Dr. Deisseroth, joining with the German researchers, demonstrated that the idea worked. And in separate research published last spring, Mr. Zhang and Dr. Boyden, now at the Massachusetts Institute of Technology, each found a way to also silence neurons: a bacterial protein called halorhodopsin, when placed in a brain cell, can cause the cell to shut down in response to yellow light....
