Biologists were able to put the signal through the eye to bypass the broken photoreceptors. To do this, they adapted the technology of optogenetics and launched in the retina of virus-like particles, which cause ganglionic nerve cells to respond to light. In the eyes of the macaque again began to react to lighting as a healthy, but how that vision will be clear, yet to be determined. Article published in the journal Nature Communications.
The retina has a layered structure. Its key element is the light-sensitive rods and cones, from which the chain of the pulse is transmitted to the ganglionic nerve cells. The axons of these cells are then collected into the optic nerve and transmit information to the brain, but they are not sensitive to light. Therefore, if due to genetic disorders or injuries refuses the photosensitive layer, the vision is lost.
Juliet McGregor (McGregor Juliette) and her colleagues from the University of Rochester were able to get vision to work without the use of rods and cones, using instead modified ganglionic cells. For this, they used the technique of optogenetics — a technology that embeds in nerve cells are the elements that make them photosensitive.
This modification is carried out using viral vectors, virus-like objects, from which the pathogenic removed parts of the code and left only what carries genetic material in the body. In this case, the inserted genes causes the cells to produce opsin — light sensitive protein the same, and so is used in the eyes.
In order to verify this idea, researchers conducted an experiment in monkeys species Monkeys-the crab (Macaca fascicularis). In their ganglionic layer were introduced viral vectors in such a way that produces the opsin cells formed a semicircle, the second half of which was left intact for visual comparison. Then, photosensitive cells have been separated from nervous, eyes began to Shine with a laser.
In the end, the nerve impulse from the modified ganglion cells from the material of the light coincided with the fact, which emit normal when stimulated from the rods and cones. Moreover, the modification worked and a year later, without causing complications. Unfortunately, visible in the monkey the image cannot be evaluated, therefore, in the near future, scientists hope to try out your method on the blind people that in the future the method could find application in clinical practice.
There are also more unusual examples of application of methods of optogenetics. So, American scientists activated the neurons synapses of the departments involved in the production of songs of Zebra finches, thus introducing information about the songs in the brain of young birds.