The electrode-stent

The electrode-stent

Interfaces the brain-computer, which were developed in sufficient numbers in recent years, allow paralyzed people to control "power of thought" specialized robotic prostheses, exoskeletons, robots, and controls the user interfaces of computer programs. In most cases such interfaces require electrodes or chips embedded in the brain surgically, which represent the minimum level of noise and interference relative to the level of the wanted signal from the neurons. However, a new type of electrode design is similar to a medical stent, can provide high quality recording from neurons without the need for dangerous surgical operations on the open brain. Electrode "stentrode", the size of a matchstick, which was developed by a group of Australian scientists, can be simply inserted into a vein that is part of the circulatory system of the brain.

Such an electrode-stent is introduced into the body through a catheter inserted into a vein in the neck of the person. This device receives electrical signals and transmits them through thin wire to the receiver, which is embedded under the skin in the region of the pectoral muscles. This receiver is also a transmitter, which broadcasts all received signals by means of wireless information transfer. The ultimate recipient of this information can be management system prostheses, exoskeletons or other electronic devices.

Testing the developed technology, scientists have produced a high quality recording of signals from neurons. The electrode-stents were introduced into the circulatory system of an experimental animal, sheep, which is no limited in its mobility. Six months of removal from the brain has enabled researchers to accumulate enough data to perform spectral analysis of signals and to calculate the value of bandwidth. All of these qualitative indicators signals almost fully correspond to the characteristics of the signals received from the matrix of electrodes embedded in the brain surgically.

The use of the electrode

The electrode-stent

The electrode-stent made of nitinol and biologically neutral Nickel alloy and titanium It is a "tube" with a diameter of 3 mm and length of 3 cm with soft latticed surface on which fortified the tiny disc-shaped electrodes. Placed inside the vein this electrode takes the form of veins and does not prevent the process of blood circulation. Bandwidth from this electrode is sufficient to ensure the removal of electrical signals from the 10 of thousands of individual neurons.

"During the first few days after the introduction of the electrode-stand gave a very unstable signal due to the interference in his work noise created by blood flow," says Thomas Oxley (Thomas Oxley), a scientist, a neurologist from the University of Melbourne, "But after six days stay in Vienna, the electrode started to give a stronger and clearer signal. Held rentgenografija showed that the outer shell of the electrode is simply rooted in blood vessel walls, which were protected from external noise. And the complete absence of processes of exclusion demonstrates high biological compatibility of the device."

Stentrode electrode allows recording of signals up to a frequency of 190 Hz. "These high-frequency signals in the range from 70 Hz to 200 Hz, are the most informative, they contain a lot of information from the motor cortex of the brain and these signals are the most useful form of signals to implement direct interfaces to the brain-the computer" said Thomas Oxley.

While Australian researchers had made no attempts to decrypt the obtained by using the electrode-stent signal. This will require at least the implementation of these electrodes in the more highly developed the animal, for example, in the monkey. "However, the veins of laboratory monkeys, rhesus monkeys, very thin for the adoption of the stent. We plan to start immediately with the introduction of these electrodes into the veins of human volunteers and then, you can begin to try decoding signals recorded from his brain" - says Thomas Oxley. Testing of the electrodes on the volunteers is planned to start in late 2017, and as volunteers will be a group of paralyzed patients receiving treatment in the Royal hospital of Melbourne, Australia.