What is "brain-computer interfaces (BCI)" which bidirectionally communicates with brain and computer?

Communication between human brain and computer "brain-computer interfaces"(BCI), it is expected that new data communication will be realized, such as creating a computer that operates just by thinking with the head, or sending video from the computer to the brain. There are many challenges to overcome in BCI research that is becoming active, such as the US Department of Defense encouraging research by issuing large subsidies.

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"Brain-computer interfaces" (BCI), which connects the brain and computer, can be used not only for the "brain wave computers" that can control computers but also for the better understanding of the state of the brain by obtaining information from the brain It is considered to be possible. Also, it is expected that perception can be reproduced by transmitting a signal from a computer to the brain that is responsible for human perception, for example, restoring lost sight.

In order to connect the brain to a computer, it is essential to first understand what is happening in the brain. About BCI It is an example of "Football Stadium" that it will come out as much as possible when discussing with neuroscientists. For example, a cheering sound from outside the stadium will let you know if a goal was born in the game. And from the helicopter flying over the stadium, you can see who decided the goal. In addition, if you are a spectator who watches in the last row of the stadium, you should be able to understand more about the situation of the game such as game development. In other words, according to neuroscientists, it is important to develop a method to accurately grasp the situation in the brain in order to understand what is going on in the "brain" compared to the stadium (game).

What is being discussed in the operation of BCI is "how close to individual neurons?" In the treatment of Parkinson's disease, it is said that "Deep brain stimulation therapy"Has already been introduced, for example, it is thought that it is necessary to control the activities of individual neurons with extremely high precision in order to create a signal for controlling fine movement such as finger movement . A method for receiving high precision signals from the brain is "Electrocorticography"Method of placing an electrode on the surface of the brain" and "Method of inserting the electrode directly into the brain" such as "


With respect to BCI, which is expected to be utilized for regaining the lost vision, etc., the US Defense Advanced Research Projects Agency (DARPA) will invest $ 65 million for six organizations conducting BCI research in 2017 7.2 billion yen) was granted. What DARPA sought is "to develop a high-performance BCI that can receive signals from one million neurons and send signals to neurons".

In the technology of reading the signal of the brain, the big problem is "to make the electrode smaller". Therefore, the mainstream of intracerebral electrodes is "small wire-shaped electrode". Dr. Ken Shepard of Columbia University who participates in the DARPA program stimulates the blind neuronsVisual cortexWe are trying to reproduce CMOS chip of type that sticks to the brain surface containing 65,000 electrodes in 1 cm square. In addition, the wire is made into a mesh and covered with a polymer, melting the polymer insidemeshApproaches such as Dr. Charles Liver of Harvard University which uses a method of expanding the range are also studied. The mesh approach seems to have the advantage of less invasiveness to the body than inserting a conventional wire-like electrode.


Of course, a power supply is necessary for electrodes to be attached to the brain surface or to be inserted into the brain. However, considering the risk of electrolyte leakage into the brain, you can not choose batteries. Therefore, securing electric power by wireless power supply using electromagnetic induction is being studied.

In addition, the technology of processing enormous sized data in transmitting the read signal is also a big issue. According to the start-up Paradromics participating in the DARPA program, the prototype is expected to need data transfer at the speed of 24 Gbps. Even the highest picture quality of movie streaming Netflix is ​​7GB transfer amount (about 16Mbps) per hour, so you can see the high data transfer rate hurdle required for BCI. In order to realize high-speed transfer, Paradromics is required to develop a method of compressing the size without deteriorating the quality of information. In addition, it seems to be a problem as to how to process the heat that would occur when processing data at high speed in the brain.


If BCI research succeeds in miniaturizing electrodes and chips, ultimately it is thought that we aim to develop "whole brain interface" covering all areas of the brain. However, if a small and flexible BCI machine is developed, there is a new problem of how to control the risk of penetrating too much into the brain. Of course, even if you can clearly transmit and receive data to and from the brain by clearing these difficulties, another challenge of how to handle that data is awaiting.