A brain that can be seen through
Scientists have created a completely transparent brain
Studying neurons individually requires cutting the brain into layers, but this method does not provide accurate data, since axons – connections between neurons and other cells - can be damaged in the process of cutting. With the help of some techniques, you can study the brain by launching a beam of light deep into its areas. But this method is not very effective, because most of the light is reflected by lipid films, which are the shells of each brain cell.
To avoid such costs, a team of scientists from Stanford University has developed a fundamentally new technology with which it will be possible to get a complete picture of the work of brain neurons.
Kwanghun Chung, Karl Deisseroth and their colleagues tested a new method on mice. They extracted the brain from the animal's skull and filled it with a transparent gel that accumulated on the surface of the lipid membranes of neurons. As soon as the gel froze, it took the form of membranes and created a matrix that holds proteins, DNA and RNA in their places. Finally, they injected a special chemical into the brain that dissolved the fat films, and the brain became completely transparent.
The technology was called Clarity. With its help, you can examine each neuron in detail without damaging the structure of the brain at all. If you add a fluorescent marker, you can see the RNA in its present place. This will improve the understanding of which genes are expressed in individual cells and what functions these cells perform.
The developers claim in a press release (Getting CLARITY: Hydrogel process developed at Stanford creates transparent brain) that the new technology will help to study not only the brain, but also any other organs. In the near future, it will be possible to make even embryos and tumors transparent, which will also allow a better understanding of their work.
To date, scientists have already managed to test their technique on a small area of the human brain – only 0.5 millimeters wide. To study a larger area, some improvements will be required, because the lipid membranes of human neurons are much thicker than mouse ones, which means they will be more difficult to dissolve.
Jeff Lichtman from Harvard University comments on the current achievement as follows: "This technique will be absolutely invaluable for studying the work of the brain as a whole. Despite the fact that at first glance the brain looks just like a bundle of tangled wires, if you look at it more closely, you can see how logically and beautifully the cells are assembled into departments, and how smoothly they work."
With Clarity, it is still difficult to consider each process of each individual neuron, but you can see which part of the brain requires close study. Moreover, research technologies can be combined, which will clearly help expand scientists' knowledge about the brain.
The results of the work of neurophysiologists and chemical engineers can be found in the journal Nature:
Chung et al., Structural and molecular interrogation of intact biological systems.
Portal "Eternal youth" http://vechnayamolodost.ru12.04.2013