The Pathways Connecting Your Brain to Computers
A quick overview of brain-computer interfaces
Intro
Imagine you're driving down a highway, going roughly 100 kilometres an hour. Your day so far has been uneventful, but that can all change in a matter of seconds. As you focus on the road ahead, the highway is full but not cluttered. Enough space to move and breathe, but not quite enough to be comfortable. But as your eyes snap back to the road, the car ahead abruptly stops. Without enough time to think, you swerve to the left to avoid hitting the car and-
You wake up two weeks late in the hospital. As you regain consciousness, something feels off. You realize that half your body feels shut down, like your brain lost connection from the waist down. And you'd be right; due to the accident, you suffered a spinal cord injury (SCI). With a complete lack of control in your legs and waist, doctors tell you you'll never walk again.
Quite a terrifying scenario, in my opinion. The fact something could happen in the blink of an eye due to something entirely out of your control, which changes your life for the worse until the day you die, is a scary thought. This seems like an unlikely scenario, but 40% of people with SCI were caused by a car crash.
SCI completely change people's life. For some, it removes the ability to walk. For others, it eliminates the ability to talk, and the list goes on. From tiny things to absolutely life-changing impacts, whatever it is, it's negative. Treatments for SCI have, up until recently, been to surgically treat damages to the nerves. Notice I said "up until recently," recently a new technology has emerged that could allow us to reconnect the brain with disconnected parts: Brain-Computer Interfaces (BCI).
What are BCIs
Brain-Computer Interfaces (BCIs) allow the brain to communicate with external devices or for devices to communicate with the brain. You can think of it as a pathway between your brain and a computer.
BCIs come in all shapes and sizes, some are as small as a single grain of sand, and others can take up entire rooms. They all have different pros and cons and work in different ways! 🧠
Spectrum of invasiveness
Invasive v Non-Invasive
BCIs work in different ways. Different techniques require more direct access to the brain. This has led to the three types of BCIs:
NonInvasive
Non-invasive BCIs are located outside of your head. None of the mechanisms or sensors are placed within your brain. A prevalent type of non-invasive BCIs is electroencephalograms (EEG for short…). EEGs use electrodes placed on the scalp of a patient to capture the action potential.
Semi-Invasive
Semi-invasive BCIs are surgically placed on the surface of the brain. These require an opening in the skull to be made to have a clear access point to the brain's surface. The most common type of semi-invasive BCIs are electrocorticograms (ECoG for short).
Invasive
Invasive BCIs are directly inside the brain. Invasive BCIs can usually measure individual neurons, making them the most accurate technique at the cost of being the most expensive, time-consuming and risky.
Electroencephalograms (EEG)
A bit of background info…
Your brain is built up by a majority of cells called neurons. Neurons behave in a giant network, communicating with each other using electrochemical pulses. Groups of neurons in different sections of your brain work together to perform individual actions. For example, a group of neurons from your motor cortex might communicate with each other and to the muscles in your legs to make you walk forwards.
This is what a Neuron looks like, kind of like a weird (sideways) tree. We'll start by looking at the dendrites. The dendrites are like the roots of the tree. They receive the signals from other neurons and send them to the soma. The soma acts as a door to the axon. It receives the signals from the dendrites and puts them in the axon hillock where they wait. When the signal becomes strong enough, the doors open, and the signal runs the hallway known as the axon. The axon acts as a hallway that brings the signal to the axon terminal, where it is then sent to the dendrites of the next neuron.
When a signal is travelling through the axon, it's called an action potential. That is what BCIs can track.
EEGs
EEGs are one of the most common types of non-invasive BCIs. They work by placing electrodes on specific parts of your scalp. Using those electrodes, we can measure when certain regions of your brain are active.
The data EEG measures (your brain activity) can be split up into five sections.
- Gamma waves
Gamma waves range between 32–100+ Hz. They are the fastest wave. Usually, gamma waves happen when you are under extreme stress (i.e. life or death situation)
- Beta Waves
Beta waves range between 13–32 Hz. They are usually the waves seen when we are awake. The frequency will vary depending on our current activity.
- Alpha Waves
Alpha waves range between 8–13 Hz. Alpha waves are seen when someone is in a relaxed state.
- Theta Waves
Theta waves range between 4–8 Hz. They are seen when someone is in deep meditation, sleeping, or other extremely relaxed states.
- Delta Waves
And finally, delta waves range between 1–4 Hz. They are found when the brain is asleep in NREM sleep (Non-rapid eye movement sleep)
Because EEGs are completely external devices, they aren't incredibly specific. EEGs can accurately tell when a big group of neurons are active but can't measure individual activations. This is one of EEGs' main limiting factors.
Once the data is gathered and processed, we send an output depending on the action we want to take. For example, if I want to detect when someone is intentionally focusing on something, I can check for a spike in the beta wave, and when I get that spike, I can perform an action.
Curing Paralysis
As I mentioned in the introduction story, we could use BCIs to cure paralysis. To do this, we would use a Brain-Spine Interface (BSI). There are a few different types of BSIs. The main distinguishing factor is whether they stimulate muscles to move or if they take the signals from your brain and send them somewhere else to handle movement (i.e. an exoskeleton).
Synchron is a company working on the second type, where the signals are sent to an external device to be then handled. Their BCI, called the Stentrode, accurately measures activity from the motor cortex without needing brain surgery. Your motor cortex is responsible for anything related to physical movement, and it stays active even if the signals don't reach their destination. To get closer to the brain, it is implanted in a blood vessel, where it travels up to the brain, right next to the motor cortex, and locks itself in position. You can watch this video to see the process.
Once the Stentrode is in place, we can use that data for a lot of things. This specific use case would be to control an exoskeleton to allow a patient to walk again. But we could use this data for other activities like typing without your hands or controlling screens just by thinking.
The other type of BSI directly uses the signals from your motor cortex and stimulates your muscles as if there was never a break in the communication. In a study by Grégoire Courtine, a neuroscientist at the École Polytechnique Federale de Lausanne, they managed to give back the ability to walk to paralyzed monkeys. By implanting a microelectrode array (a type of semi-invasive BCIs) into a monkey's brain, and an electrical stimulator to transmit the signal, they were able to repair the monkey's broken link, and it was able to walk again after six days. (Quick video showing the process)
This technique is still in early development, and we still need to be realistic with our expectations. Many of the injuries it can help with would have healed naturally eventually, but this BSI allowed them to keep communicating during the healing process.
Startups in the Space
These are a few of the startups I'm most excited about!
Nextmind
LET YOUR MIND TAKE CONTROL
NextMind has developed a portable EEG that you can clip onto a hat/VR headset or wear as a headband. The headset is built using eight comb-shaped electrodes placed over your visual cortex.
It collects data and identifies active visual focus. It works by having the software flash specific patterns on images/objects that are barely noticeable, but the headset picks it up. Those are called NeuroTags. After the data is gathered, it's decoded by machine learning algorithms and recognizes which pattern is being focused on. And as a final step, it activates, sending over the command based on what you are focusing on.
You can watch the founder talk here!
Their current development kit includes a Unity SDK to make developing with NextMind much easier!
Neurable
The mind. Unlocked.
Neurable is another BCI company working on a bunch of awesome projects! Their primary focus at the moment is on Enten, smart EEG headphones to help you focus during your workday.
Neurable is still in the prototyping stage for Enten but is accepting pre-orders here if you are curious! Enten uses 16 soft EEG sensors embedded inside the headphones, so you wear them normally, and Enten helps you focus by collecting data and letting you know the best times to work, where to work, and how to work!
Kernel
A New Era for Neuroscience
Kernel is developing a platform to quantify the human brain. They could measure attention, arousal, pain, memory, imagination, etc., with actual data instead of subjective thoughts.
They currently have two developed products, the Kernel Flow, a non-invasive headset used to record precise patterns in brain activity. And the Kernel Flux, which is an incredibly accurate and fast headset. They achieve this by using magnetoencephalography (MEG) to get higher resolution, speed, and fidelity for the sacrifice of movement and portability.
Conclusion
BCIs could change the way we live our everyday lives, either with a very drastic change by directly implanting BCIs inside our heads or just by wearing tech like Neurable's Enten. There are a lot of unknowns left with BCIs, which is mainly because of the minuscule amount of knowledge we know about our brains. BCIs could also help us bridge that gap, bringing us more information the more we use them. BCIs have so many applications, so many more than the few I've mentioned in this article. And for every new application, moral dilemmas and issues emerge following them. BCIs are complex problems that will take time to solve. But by taking our time, I genuinely believe that BCIs will revolutionize our lives for the better.
