manipulating nerve cells makes mice ‘see’ something that’s not there - laser light measurement device

Shining a laser into a mouse's brain allows them to "see" lines that don't actually exist.
This result, described online in July 18, represents the first use of laboratory means by scientists.
The work is "technically amazing," said Kono Liston, a neuroscientist and psychiatrist at wilcornell Medical School in New York City.
"I think every neuroscientist in this field will look at this issue with great interest.
"The ability to monitor and control the precise collection of nerve cells or neurons may help to solve some big problems, including how certain groups of neurons create experience.
Experiment used, a technique for laser activation of brain neurons ().
Neurons are genetically adjusted to carry a protein that causes them to signal light.
Karl Deisseroth said that when light genetics made its debut about 15 years ago, everyone wanted to reach a level of precise control over perception and subsequent behavior, pioneering neuroscientists and psychiatrists of the technology
"It's exciting to achieve this," said Deisseroth, a researcher at Howard Hughes Institute of Medicine at Stanford University.
Deisseroth and his colleagues first monitored neurons in the brains of mice that observed horizontal or vertical lines.
When each mouse sees the direction of the lines it has trained, it is trained to lick water from the spout in front of it.
The researchers then began to manually evoke the same vision of these lines.
At first, the mouse was shown a very weak solid line.
When lines become so weak that mice struggle, genetic stimulation of light improves their performance.
The researchers then tested the mice in a completely dark environment, without any visual input, and found that the perception of the lines could be generated only with a laser.
Stimulating about 20 neurons that respond to real vision causes mice to "see" the correct vision correctly and thus lick it.
The progress of this positive result has created the climax of "Oh my God, this is actually effective" slowly accumulating!
"Said Deisseroth.
These artificially stimulated neurons initiate cascade responses from other neurons, suggesting that the visual part of the brain responds as normally to real vision.
Deisseroth said that some key advances have led to the success of the experiment: precise lasers carefully controlled by liquid crystals, as well as the discovery of a new light
The protein that reacts is called ChRmine.
Even dim light can activate the protein, a useful feature because too much light can damage the brain.
A similar approach allows scientists to generate other types of perception, such as smell, touch, and taste, Deisseroth said.
This approach also allows researchers to control the number of neurons involved in more complex brain tasks.
"For example, you can easily imagine using similar tools to study memory," said Liston . ".