A new method, which makes it possible to control the growth direction of neural processes using a laser beam, may help in the future in the treatment of brain injuries, in the development of electronic prostheses and computerized hearing aids
Yanai Ofran, Haaretz, voila!
Nerve cells and their extensions
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An American-German team of researchers managed to direct the growth direction of nerve cells with the help of a laser beam. This could be a significant breakthrough in the treatment of brain injuries, as well as in efforts to develop electronic devices based on nerve cells.
A single nerve cell can reach a length of more than a meter. Although the cell body is a tiny bubble that is less than a millionth of a meter in diameter, it sends out long extensions that transmit messages to distant cells. In the last year, the signs are increasing that it will soon be possible to encourage the creation of nerve cells in the brain and spinal cord to overcome injuries or diseases. The problem is that it is still very difficult to control the growth of nerve cell extensions and direct them to the desired areas.
The aspiration to control the growth direction of neural processes does not only stem from medical motivations. Neuroscientists like to simulate the brain to a computer. But there are operations that the brain easily performs within a fraction of a second, while computers, even supercomputers, have difficulty performing even after a long effort.
For example, a computer would need many hours to calculate the force that needs to be exerted on each muscle in the body to maintain an upright posture and prevent a fall, but the brain performs this task as a matter of course. This is one of the reasons why researchers are trying to develop computers, which will be based on nerve cells and not on electronic circuits. Such computers, the developers hope, will be able to perform calculations that electronic computers are not capable of. But to develop such a system, of course, the growth of nerve cells must be controlled.
Whoever succeeds in developing a successful interface between nerve cells and electronic systems will be able to greatly improve the electronic prostheses that have been developed in recent years. These prostheses are robotic arms operated by a computer, which receives instructions from the motor control centers in the brain. Innovative hearing aids for the deaf, which convert sounds into electrical signals and transmit them to nerve cells, are also based on such a neuro-electronic interface. To improve these interfaces, researchers have been trying for years to grow nerve cells on silicon chips - so far with only partial success. The key to the success of these efforts is the ability to control the direction of growth of nerve endings.
Breakthrough: A laser beam grips the nerve endings like tweezers
Alan Ehrlicher from the University of Leipzig revealed this week the solution he and his team developed. They were based on a technology developed in the seventies and called "optical tweezers". This tweezer is a powerful laser beam, with which you can grab and pull tiny objects like single molecules. Ehrlicher used a weaker laser beam, and captured the tip of a nerve extension as soon as it began to develop.
In an article to be published in two weeks in the journal PNAS (Sciences) the National Academy of (Proceedings of) the team will reveal images of laser guided cells. The extensions of these cells obeyed particularly capricious dictates, growing in zigzags and making sharp turns (videos can also be viewed on the journal's website).
Experts who analyzed the technology of Ehrlicher and his team confirmed that this is a significant breakthrough. No one before them had managed to achieve such good control of the nerve endings without damaging them. It is likely that it will be possible to translate the team's initial experiments into a technology that will also be applicable inside the body of patients, through the implantation of optical fibers for example. But the commentators also point out that it is very difficult to understand how the technology works - why the branch is attracted to the laser beam, and how and what causes it to change its direction of growth. Ehrlicher also admits that he does not understand exactly what makes his method successful and how the laser beam guides the cells. But the fact is that technology works, and in the world of research and development, successful technology with lame explanations is better than lame technology with successful explanations.
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