Brain-Computer Interfaces
All of our interactions with the outside world are regulated by our nervous system. Today’s technology is allowing us to take our abilities a step further through brain-computer interfaces. These devices create another method of communication between our brains and the outside world.
Brain-computer interfaces (BCIs) are an exciting development because they can help us treat neurological conditions such as seizures and depression, and they can change the game in terms of how humans interact with technology. However, let’s not forget this emerging field is riddled with ethical issues we will have to confront as we are implementing its technologies. But before I delve too deep into the future of BCIs, let’s take a quick look at our brain structure.
Brain Structure
Our nervous system is made up of cells called neurons. This is what a neuron looks like:
As shown above, neurons have a main cell body called the soma. The soma is much like any other cell in the body. It contains a nucleus with DNA, mitochondrion, smooth and rough ER, and other cellular structures.
Though the structures above are common to many cells, neurons also have a unique extension called an axon. Axons are important because they send signals called action potentials that neurons use to communicate with each other. An action potential is an electrical signal. A neuron that is at rest typically has a negative voltage inside compared to its surroundings. If a neuron is stimulated in a way that will cause its voltage to approach a threshold value of about -55 mV, it will fire an action potential.
Action potentials are binary, meaning they will either occur or not, based on whether the threshold voltage was reached or not. There are no “weaker” action potentials.
If the threshold is met, the neuron sends an action potential down its axon. Then the axon terminals, at the end of the axon, are stimulated to send out neurotransmitters to another neuron. Neurotransmitters are usually amine molecules, amino acids, or a kind of peptide. The second neuron will receive these molecules through its dendrites. These molecules can either excite the receiving neuron and cause it to fire its own action potential, inhibit it from firing an action potential, or affect its state in another way. In this way, neurons communicate with each other and our brain processes outside world stimuli.
The web of neurons is huge. There are about 86 billion neurons in our brain alone, and there are also sensory and motor neurons in our peripheral nervous system which reaches everywhere else in our body. The number of connections, or synapses, between neurons is 125 trillion in the outer layer of the brain alone. For reference, that’s about how many stars would be in 1,500 Milky Way Galaxies.
How BCIs Work
So how do BCIs interact with brain activity? A BCI is a computerized system that acts as a bridge between your brain and an external device. While advancing our research in neuroscience, we have been able to better understand the connection between brain signals and the effects they create, such as muscle movements or gland activity. This has allowed us to create algorithms that can use brain signals to recognize specific commands, and then execute those commands on an external device, such as a mouse on a computer monitor. An example of this is when researchers had subjects move a dot across a screen by looking at a light that meant “right” or a light that meant “left.” These lights flashed at different frequencies. Our brain will have different activity based on the frequency of light that we look at. The BCI will be able to recognize the pattern of brain activity that means “right” and move the dot on its own. Though this may seem like a small accomplishment, same principle can be extended to move prosthetics for those who are paralyzed, or, further in the future, to send our thoughts to one another.
The BCI Technologies
BCI technologies can be both noninvasive and invasive.
An electroencephalogram (EEG) is a noninvasive technology that consists of a web of electrodes which sit on top of the head. An EEG generally comes in the form of an electrode cap as seen below:
EEG BCIs are used to measure the electrical activity in the brain. The EEG system can identify simultaneous activity of large groups of neurons but it is not precise enough to identify the activity of a single neuron. EEG is the most appropriate method of recording neuron activity as it occurs. At a more detailed look, EEG measures the post-synaptic potential that is created when neurotransmitters bind to receptors on their receiving neuron. The data collected from EEGs is in the form of waves, as in the picture below.
This data can be used to describe brain activity during a specific event, for example, when a light is flashed in front of the eyes, or to diagnose certain neurological conditions such as seizures. The drawbacks of EEG is that it has poor spatial precision, meaning it cannot accurately sense activity from neurons deeper in the brain. Its accuracy may also be affected by having to read through the scalp.
An electrocorticography (ECog) is an invasive type of BCI technology. This technology consists of electrodes which have to be directly placed onto the surface of the brain through surgery. It has a much higher spatial resolution than EEG, meaning it can pin-point neurons more precisely and read deeper into the brain. Though there are some risks associated with electrode placement and the technology is generally more expensive, ECog can make an enormous difference for patients suffering from epilepsy or paralysis.
Applications in the Medical Field
BCIs have proven to be particularly useful in treating neurological conditions. The oldest and perhaps most well-known BCI is a cochlear implant, which is used to partially restore hearing. Invented in 1957, the cochlear implant does not amplify sound in the way a hearing aid does. Instead, it completely bypasses the ear and connects to the auditory nerve in the brain. A patient will wear a sound processor behind their ear which picks up the sound. The signals will then stimulate the auditory nerve and be sent to the brain. The brain will process the signals as sound, though the sounds are not exactly how “normal” sounds would be heard. As a result, it takes some training to learn how to use a cochlear implant, but it is still an amazing breakthrough that allows hearing to be partially restored to the deaf.
BCIs have also been used to treat seizures with a kind of pacemaker for the brain. Neuropace is a company pioneering this technology, and they describe their device as a “small, implantable neurostimulator connected to … tiny wires that are placed in up to two seizure onset areas.” The device is then able to measure electrical imbalances in the brain that can lead to a seizure and counteract them before the seizure occurs. This preventative system provides relief for patients experiencing chronic seizures.
Another interesting use of BCIs is in analyzing migraine headaches. Although very common, migraine causes are still not well understood. The study “Extraction of SSVEPs-Based Inherent Fuzzy Entropy Using a Wearable Headband EEG in Migraine Patients” by Zehong Cao et al is trying to advance our understanding of migraines and find a method to alert patients before a migraine occurs.
One of the most interesting and perhaps well-known applications of BCIs is helping those who are paralyzed regain their ability to move. The implants are able to pick up signals from the motor cortex (the section of the brain that controls movement) and decode what the intended movements are. Then the implant send a command to an external device so that the movement is executed. This type of BCI system can be used with exoskeletons and prosthetics. The study “Brain-computer interface enables people with paralysis to control tablet devices” from Brown University demonstrates how BCIs can allow paralyzed patients to manipulate tablets in order to message their families and even shop online.
BCIs are also being investigated as a potential treatment for psychological conditions such as depression and anxiety. Researchers believe they can use BCIs to train people to regulate their brain activity in order to feel calmer and happier. The patients thus trained, should eventually be able to regulate their brain activity without the use of the BCI.
Communication with Technology And Each Other
Advances with BCIs are not limited to the medical field. Another exciting application is human interaction with technology through BCI. One idea is that, in the future, BCIs may allow us to store our thoughts or experiences in the Cloud and thus creating a shared memory.
BCIs have already reached the stage in which we can create very low-grade telepathy.
A study from the University of Washington demonstrated this by having two people in separate rooms, each connected with a BCI. Together, they would have to play a video game, but neither would be able to complete it on their own. The first person saw when the city in the game was being attacked, but could not fire the cannon to defeat them. The second person could not see the game at all but had the keypad that controlled the cannon. The BCI would pick up signals in the first person’s brain when they wanted to shoot the cannon, and send them over the Internet to the second person, who would then click the keyboard. In the future, we may be able to send our thoughts, or even feelings, to one another in a similar way.
Potential Concerns
Of course, this emerging field has brought ethical dilemmas with it, especially because these devices are connected to our brain. Some of the most prominent ethical dilemmas surround privacy, and who will be able to have access to our brain activity if BCIs become mainstream. Another concern is that people will be able to “hack” into the brain activity of others through BCIs, giving them access over thoughts and feelings and potentially being able to control the other person. Ethical committees are tackling these issues as they arise, and many neurotechnology groups have professionals specialized in ethics working with their teams to ensure that the technologies being built will be as ethical as possible.
Summary
Brain computer interfaces are an emerging field of technologies which provide a connection between our brain activity and external devices. They utilize noninvasive technology such as EEGs or invasive technology such as ECogs. BCIs have wide applications within the medical field, but can also create a new way for us to communicate with technology and one another. Because BCIs are connected to our brains, we must consider the ethics of these technologies and potential issues that may arise if they become widely used by society. However, these devices have shown that they can greatly better the lives of people, and I am looking forward to seeing how they develop further and what other breakthroughs they will bring.
Citations
Ma, Michelle. “UW Study Shows Direct Brain Interface between Humans.” UW News, University of Washington, 5 Nov. 2014, www.washington.edu/news/2014/11/05/uw-study-shows-direct-brain-interface-between-humans/.
“People with Paralysis Control Robotic Arms Using Brain-Computer Interface.” News from Brown, Brown University, 16 May 2012, news.brown.edu/articles/2012/05/braingate2.
