About BCI

BCI is the abbreviation for “Brain-Computer Interface”, also known as “Brain-Machine Interface” (BMI), “Direct Neural Interface” (DNI) or “Mind-Machine Interface” (MMI). All these names stand for a direct communication gateway between the brain and an external device (computer).

The traditional definition of BCI, according to the Wadsworth Center,  is: “The goal of BCI technology is to give severely paralyzed people another way to communicate, a way that does not depend on muscle control.” (quote from the lecture “Introduction to Modern Brain-Computer Interface Design” – Christian A. Kothe, Swartz Center for Computational Neuroscience, University of California, San Diego)

Application of BCIs

BCIs mainly serve as devices to assist people with impaired cognitive or sensory-motor functions and aim at assisting, augmenting or even repairing these. An example is the research regarding the restoration of damaged hearing, sight and movement with the use of neuroprosthetics applications. The brain can learn to handle signals from such implanted prostheses like natural sensor or effector channels, although a phase of adaptation is necessary. First neuroprosthetic devices were implanted in humans in the mid of the 1990s.

Another application area is the use of motor neuroprosthetics for people with paralysis, in order to restore movement or to at least assist them through the use of interfaces with computers or robot arms.

BCIs are subject to ongoing research and experiments, with some applications still in the realms of theory, while some some devices are already produced commercially in order to be used in medical research.

Types of BCIs

There are different types of BCIs –  invasive, partially invasive and non-invasive – aimed to be used for different treatments and with their own comparative advantages and disadvantages.


Invasive BCIs require neurosurgery, during which they are implanted directly into the grey matter of the brain. Due to their location, these invasive BCIs produce signals of a very high quality. The problem is, that the body recognizes these devices as foreign objects, which can damage the functioning of the BCI: The build-up of scar-tissue can interfere with the signals, weaken them or even cause them to vanish.

The research into the use of invasive BCIs targets the issues of damaged sight as well as paralysis.

Partially Invasive:

Partially invasive BCIs are implanted into the skull as well, but are not implanted within the brain, i.e. the grey matter. Therefore, the risk of their signals being impeded by the build-up of scar-tissue is lower than with fully invasive devices. Due to the only partial invasiveness, their signals are not as strong as with fully invasive BCIs.

The applied method to measure the electrical activity of the brain from beneath the skull is Electrocorticography (ECoG) or intracranial EEG (iEEG). This is the practice of using electrodes placed directly on the surface of the brain to record electrical activity from the cerebral cortex


Non-invasive experiments use the technology of neuroimaging interfaces by means of Magnetoencephalography (MEG), functional magnetic resonance imaging (fMRI) and Electroencephalography (EEG), which is the most studied potential non-invasive interface. Non-invasive BCIs are of course much easier to attach to the head of patients and easy to wear. A problem is, that the recorded signals are weaker and less clear, because they are dampened by the skull. Still, they have been used in experiments to restore partial movement.


The history of BCIs starts in the 1920s: The German neurologist Hans Berger discovered the electrical activity of the human brain, and in 1924, he was the first to record this activity in a human brain, using a device he invented and developed for this purpose: the EEG or “Electroencephalography”.

The expression “brain-computer interface” first appeared in scientific articles in the 1970ies, following the first research on BCIs at the UCLA (University of California Los Angeles) under a grant of the National Science Foundation and later a contract from DARPA (Defense Advanced Research Projects Agency, an agency of the U.S. Department of Defense.

1998 the first brain implant that produced high quality signals, enough to simulate movement, was implanted into a human brain. This was achieved by researchers at Emory University in Atlanta, USA, a team led by Philip Kennedy and Roy Bakay. The name of their patient who received the treatment was Johnny Ray (1944–2002). After a brain-stem stroke in 1997 he suffered from the so called “locked-in syndrome”, a condition that left him aware but completely paralyzed without being able to verbally communicate. Johnny Ray started training with the implant and learned to control a computer cursor, but he died of a brain aneurysm in 2002.

Matt Nagle had sustained a stabbing injury in 2001, which had left him paralyzed from the neck down. He agreed to participate in the first nine-month clinical human trial regarding the BrainGate Neural Interface System (developed by Cyberkinetics). He received the implant of the device in 2004 by neurosurgeon Gerhard Friehs. The implant was placed on the surface of the brain, above the area of the motor cortex. A link connected the chip-implant to the outside of his skull. From there it could be connected with a computer, which was trained to recognize Matt Nagle’s thoughts and “translate” them into the movements of a robotic arm with an artificial hand. He was the first person to control an artificial hand (open and close) via BCI.

I can’t put it into words. It’s just—I use my brain. I just thought it. I said, “Cursor go up to the top right.” And it did, and now I can control it all over the screen. It will give me a sense of independence.

—Matthew Nagle, “Brain Gain”

Since then, the research on BCIs has progressed, and further success has been achieved regarding the the BCI control of robotic prosthetic limbs, namely by the Braingate group at Brown University and a group led by the Medical Center of University of Pittsburgh. Both groups collaborate on this line of research with U.S. Department of Veterans Affairs.

Synthetic Telepathy

Synthetic telepathy or “silent communication” is a different angle of research that is based on “subvocalization”, the process of internal speech while reading a word: The readers imagine the sound of the words, while reading them (“imagined speech”), which provides a basis for research into synthetic telepathy through BCI technology.

In 2014, scientific successes were reported regarding the possibilities of direct communication between human brains – even over long distances – through the transmission of EEG signals via the internet.

Other Applications

Other applications include early stages of “Neurogaming” with the use of non-invasive BCI, for example the interaction of the user and a game console without the use of a joystick, a computer mouse or other traditional game controllers.

There are also smartphone apps already available that interact with a special EEG headset and use biofeedback to help with relaxation training, meditation etc.

Ethical Concerns

There is an array of ethical issues connected with the research and use of BCI, ranging from proper risk/benefit analysis and the providing of informed consent from people whose natural communication capabilities are limited or impeded, up to possible medical side effects and concerns regarding mind reading and mind control.

In “Man, Machine and in between” (2009) Jens Clausen compares these BCI-related ethical issues with “those that bioethicists have addressed for other realms of therapy”.