Animal behavior is usually governed by the method of "carrot and stick". This method - hundreds, even thousands of years. It's simple: well behaved pet or laboratory animal - it receives remuneration in the form of food is bad - snacks are canceled should be some punishment. At Stanford we decided to go further. Neuroscientists from the university set out to learn how to control the behavior of the mice using a wireless optical neyroimplanta. It has no effect on brain neurons electrocution. Instead, the light is implanted LEDs.
The implant has a very small size - about a grain of pepper. To prepare the mouse for use with the implant was conducted fairly large-scale training, and carried out its genetics. Rodents introduced gene, which provides a reaction of the brain neurons to blue light. When the behavior of the mouse control system, an implant in the skull begins to glow and the glow react some of the brain cells of mice. In the video posted below, clearly shows how after the system of the mice involved in the experiment stops the chaotic motion and begins to run well around in his cage. What is this all for? Experts say that method will help find a solution to the problem of the treatment of neurodegenerative diseases such as Alzheimer's or Parkinson's.
Optical-Electrical animal behavior control methods recently described in a variety of science fiction. But now it is, as far as can be judged, is already a reality. Penetration of future technologies today helps, in particular, optogenetics. New methods of scientific branch (it appeared in 2005), recently developed by scientists, allow the use of light to activate virtually all brain cells and activate specific neural connections. When exposed to light animal behavior changes dramatically, they begin to do what the researcher expects. One objective of these studies - obtaining more information about the structure of the brain and nervous system.
For optical exposure methods neurons main problem is to provide the access of light in the skull of a living being. It's not so easy. Some scientists solve the problem by means of fiber-optic cables (very fine), implanted into the skull and then some covering the lobes of the brain in blue (in this case) light. There are scientists who are experimenting with LEDs and miniature systems based on them. According to Ada Poon, senior associate professor at Stanford, the best option is not the fiber in the skull, and the wireless module with LED implanted in the skull. It does not prevent the animal to lead a normal life and is not particularly affect the health of mice.
However, no fibers, no cables, no, it works wirelessly. Electronics are now allows us to develop much smaller device than a rodent head in implantable wireless communication modules. signal transmitter is placed under the cage, which ensures stable reception teams implantable module.
Above I mentioned that in order to respond to light mouse brain cells should be genetically modified. This is true. The gene which allows the cell to be a reaction to light, has been removed from the unicellular green algae. These algae can be moved in the direction of the light source due to the presence of a particular protein in the cell membrane. Protein interacts with light radiation in a special way - it opens the ion channel in the membrane by changing the electrical potential of the cell. As a result, the algae will be able to move. In 2005, several groups of researchers have realized that this gene can be used for the introduction of DNA into a neuron.
After such modification gets the same neuron cell membrane protein that can react to light. Now, if the neuron to light, opening ion channels, and ions enter the cell. This process provokes a change in electric potential that activates neurons. He starts to produce a special chemical that triggers, in turn, neurons that are close by. As a result, certain activated part of the brain and the animal responds accordingly. It may be some kind of animal action (running in a circle, which was already mentioned above), or the general reaction of the organism (a dream, the manifestation of certain emotions, etc.).
Seeing the reaction of the animal to understand how activation of one or another group of neurons affected by the actions of an animal, the work groups of different muscles and other processes. Some neuroscientists using conventional electrodes implanted in the brain of an animal, and then experimenting, including current and activating a group of neurons. But such systems are very inconvenient, they interfere with the animal and can not fully ensure the purity of the experiment. Furthermore, this method is unable to provide a job to a group of cells - such as neurons in the hippocampus, which are responsible for certain memory processes.
Optogenetics removes the animal from most of the disadvantages associated with the presence of the electrodes, supplied to the head, and allows the researcher to work in a comfortable environment, which, above all, allow for "pure" experiments. Neurons respond to light for a few milliseconds, there is no delay. Optogeneticheskih advantage over conventional methods of studying electrophysiological techniques of neural networks and their impact on capabilities is highly selective activation or suppression of specific neural connections. This selectivity opens new possibilities in the treatment of Parkinson's disease, depression, anxiety and epilepsy.
Studies are performed neurobiologists, gradually helping to understand what a Parkinson's disease and how it can be treated (as possible). In one study, researchers stimulated monkey brain are neurons that are responsible for producing dopamine - it plays an important role in motivating, controlling movement, he is also responsible for addiction to anything. One group of researchers trying to understand how damage to cells producing dopamine, can affect the movement of the animal. These studies have given scientists a lot of valuable data that help treat complex diseases of this type.
The goal of Ada Poon - optogeneticheskoy creating a system that will allow the mouse normally feel in a familiar environment. In this case, neuroscientists can easily study the characteristics of the various regions of the brain to give a great deal of important information that will help in the treatment of neurophysiological disorders.
The apparatus, which is used in the rodent
Poon said that the wireless system and optogenetics - the future of neuroscience. Incidentally, there are other types of wireless systems that are used in the art. Many of them use electromagnetic induction as the basis of their work. The signal receiver is implanted in the mouse brain, and the transmitting device is located nearby. But this type of system has a number of drawbacks. First and foremost, is to maintain the functioning of a strong electromagnetic field and the complexity of the cage with the definition of animal movements.
Poon and his colleagues decided to take advantage of the fact that the body of virtually any animal - this is a good conductor, who will interact with the radio waves, changing it depending on the shape and properties of the body. Special software has been developed that track the places where electromagnetic radiation is "deformed" in a certain way the body tissues of the mouse. It created a special equipment which, according to developers, picks up all the distortion with a high degree of accuracy, and tracks the location of the animal at any time. To simplify the work, researchers used RF-tag, which constantly generates persistent radio signals.
Implant mouse brain
It is a system of small inductive coils, and the LED control element. the device weighs just 20 milligrams, that is not a problem for the mouse. The volume of the device - 10 cubic millimeters.
Ada Poon states that such equipment complies with the requirements of the scientific equipment. The project team has published detailed information on the assembly in the network system. In addition, there is a video tutorial on the operation of the system. Wireless signal transmitter is built using common tools and inexpensive components, which can be bought in any radio. This system allows the neurons to react to a stimulus quickly, and then the computer keeps track of animal movements.
According to the developers, what they posted description of the construction with the necessary data on its manufacturing will help scientists quickly get started with optogenetics. The very design of the proposed system is much simpler to implement than the construction of similar systems. Create it can be using widely available tools and inexpensive materials.
Optogenetics and related devices, probably soon be used in medicine. In any case, this opinion was expressed by many large organizations. However, when this might happen - say so far no one can. Researchers must ensure safe use of work methods before implementing them throughout.
In addition to Parkinson's disease, as described above, such a system will allow to study the causes and course of Alzheimer's disease. The traditional method of studying this disease - the work with mice in the laboratory. The laboratory, which employs Poon, is now working to apply its development in the study of the mechanism of memory loss in the early stages of the disease. Scientists are looking for a cure of the disease or at least a way to slow down the development of Alzheimer's disease.
Perhaps the new data will help scientists develop treatments for the human nervous system. If something does not work somewhere, "short-circuited" system - doctors in the near future will have a tool for solving such problems. In any case, it expects the project team.
Now scientists have learned to directly activate a group of neurons that are responsible for certain functions of the phone's memory. So in memory of rodent can cause flashback, for example, the fear has gone through in the recent case of fear or to receive a painful shock. Physicians in certain cases use implanted electrodes for treatment of several neuropsychiatric and neurodegenerative diseases. According to the project team, the electrodes can be replaced without problems optogeneticheskimi systems in which small size and high selectivity of the work, and what was said above. Optogenetics itself, according to Poon and colleagues may well be the guiding light for neuroscientists. Who knows, maybe it is.
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