Russian scientists are developing a compact and cheap MEG system

    A group of scientists from the Higher School of Economics and the St. Petersburg Ioffe Physicotechnical Institute are working on a new generation of atomic magnetoencephalographs, the newspaper Izvestia writes . If the work is completed, the Russian invention will compare favorably with the existing expensive MEG devices worth several million dollars:

    • It does not require a magnetically insulating room. The sensor works in the magnetic field of the Earth
    • The cost is 5–7 times cheaper than analogs (since there is no need for special equipment for a magnetically insulating room)
    • Compactness
    • The location of the sensors is closer to the head than the minimum distance of 3-4 cm in existing MEG systems, where this restriction is caused by the fact that the sensor is placed in liquid helium at a temperature close to absolute zero.

    The work is still far from complete, but scientists have achieved some success. The most important thing is that a key element of the future device has already been designed - a sensor that registers the magnetic fields generated by the activity of the nerve cells of the brain.

    In modern MEG, SQUID- type sensors (superconducting quantum interferometer) are used. This is a superconducting ring with two Josephson tunnel contacts. This is in a certain sense an analogue of the optical effect with interference from two slits, only in this case it is not light waves that interfere, but two Josephson currents. In SQUID, the electron wave is divided into two, each of which passes through its tunnel junction, and then both waves are brought together. In the presence of a magnetic field in the circuit, a circulating superconducting current will be induced. This current in one of the contacts will be subtracted from the direct external current, and in the second - to add to it. A phase difference will occur between the tunnel contacts.

    For SQUID magnetometers existing in the world, the sensitivity reaches 5 · 10 −33 J / Hz (the sensitivity in a magnetic field is 10 −13 T). Naturally, they need isolation from the Earth’s magnetic field.

    “During the development of the atomic magnetoencephalograph, we were able to design sensors capable of operating in the Earth’s magnetic field,” said Anton Vershovsky, a leading researcher at the Laboratory of Atomic Radio Spectroscopy, PTI. “This, perhaps, will make it possible to refuse to use a magnetically insulating room, which will considerably reduce the cost of the device and its operation.

    In the comment for Geektimes Anton Vershovsky ( antver) explained: “Our prototypes and competitors are not SQUIDs, but SERF sensors are atomic magnetometers capable of operating only in zero magnetic fields. Our sensors are slightly less sensitive, but they lack this disadvantage. The magnetically shielded room with the cost of half a million dollars, which is needed by sefes, can really be dispensed with, but a magnetic screen with a field stabilizer will still be needed ... So far, the physical principles of the sensor have been developed and experimentally verified. The next stage - OCD - the design of the sensor, and only then MEG. It's not one year. ”

    There are few technical details about the revolutionary Russian system (although there are publicationson atomic magnetometers). But Alexey Osadchiy, director of the Center for Bioelectric Interfaces at the HSE, said that the new sensor makes it possible to construct a compact MEG system with qualitatively new features: “It will be something like a fantastic headdress from Professor Back to the Future,” a helmet spiked with a couple of hundreds of sensors similar on a big souvenir pencil. The sensors will be located no more than half a centimeter from the head - several times closer than in existing systems. This will allow to achieve a submillimeter resolution: we will be able to distinguish signals from brain regions that are less than a millimeter apart from each other. ”

    Even if we assume that the Russian development will not be brought to its logical conclusion, there are still several groups in the world who are conducting scientific research in this direction. In other words, sooner or later a compact atomic magnetoencephalograph should be created that is much cheaper than the existing MEG systems. And such a device will produce a real revolution in the science of the brain.

    The fact is that current devices of several million dollars require complex installation and maintenance. They are very expensive so that MEG can afford an ordinary district hospital. In addition, they have a number of other restrictions. For example, an absolute immobility is required when scanning. It is impossible to scan the brains of children or animals, because they have a head size smaller than the standard. New sensors and an atomic magnetoencephalograph will remove such restrictions and drastically expand the scope of MEG use: “The appearance of an inexpensive magnetic encephalograph will revolutionize both the treatment of neurocognitive disorders and science,” said Tatiana Stroganova, director of the Center for Neurocognitive Research at the Moscow City Psychological and Pedagogical University. “Even small medical and scientific institutions will be able to afford the MEG installation.” In her opinion, the multiple increase in the volume of MEG studies worldwidemake inevitable a qualitative leap in the field of man’s knowledge of his brain .

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