Brain-Computer Interfaces: The Promise of Technological Telepathy and More
What are brain-computer interfaces, where is the technology today, and how it promises to unlock full human potential
Brain-computer interfaces (BCIs) are often portrayed in science fiction stories, and the possibility of using them to merge human brains with machines to enhance our capabilities is a common topic of discussion in transhumanist circles. These devices, also known as brain-machine interfaces (BMIs), establish a direct communication pathway between the brain and an external device, such as a computer, a robot or a prosthetic. BCIs enable individuals to control or interact with technology using their brain activity, or thoughts, alone.
BCI technology has seen steady progress over the last 10 years. The entry of some high-profile players in the neurotech field, such as Elon Musk's Neuralink, which aims to unlock the full potential of the human mind, has brought more attention and more investments into the field.
In this article, which is part one of three in the series, we will focus on what brain-computer interfaces are, where is the technology today, and how it promises to unlock full human potential. In the second part, we take a closer look at the BCI landscape and the leading companies in the field. The third part discusses potential issues with this technology and how to address them to make BCIs not only safe but also beneficial.
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We can trace the origin of what would become brain-computer interfaces back to 1924, with Hans Berger's discovery of the electrical activity of the human brain and the development of electroencephalography (EEG). The first tests of what we can call BCI were carried out on monkeys in 1969 and 1970, while the first attempts with humans were performed in the 1990s. The field gained more attention from entrepreneurs, investors and the public since Elon Musk founded Neuralink in 2016. He wasn’t the only billionaire to enter the neurotech space around that time; also in 2016, Bryan Johnson founded Kernel, and a year later, Facebook announced they are working on a BCI, too (Facebook shut down the BCI project in 2021).
BCIs can be divided into two broad groups - non-invasive, which do not require any surgery to be used, and invasive, which require surgery as these devices are placed on the surface or inside the brain.
We will be using two metrics to describe different types of BCIs - spatial and temporal resolution. Spatial resolution describes how finely the device can map and differentiate areas of brain activity. Temporal resolution, on the other hand, refers to the device’s ability to track changes in brain activity over time, meaning how quickly and accurately it can detect changes in neural signals.
In this article, we will focus on devices that read and interact with the brain, which, along with the spinal cord, forms the central nervous system. There exist devices designed to listen to the peripheral nervous system (the network of nerves branching off from the central nervous system), and we will not be discussing them here in detail.
Let's start with non-invasive BCIs. We will focus here on non-invasive brain recording devices. There are also non-invasive brain imaging devices, such as MRI, fMRI, PET scans, or CT scans, which we will leave out.
Devices in this category do not require any surgery as they are not placed inside the head. Because of that, non-invasive BCIs are considered safe and pose little to no risk to the wearer. They are also cheaper, can be easily put on and taken off, more accessible, and easier to use.
However, what makes them safe—being outside the brain—also causes issues. Since the electrodes are placed on the head and not inside the brain, they cannot record brain activity with high spatial resolution. They also have to deal with the skull and tissues standing between the electrodes and the neurons, which reduces the already weak signals generated by neurons.
Recent advancements in AI could significantly boost the capabilities of non-invasive BCIs. In March 2023, two researchers successfully recreated images from the brain using latent diffusion models. Just a couple of months later, another group of researchers captured exact words and phrases from the brain activity of someone listening to podcasts. These results could greatly improve the accuracy of non-invasive BCIs and make them a viable alternative to invasive BCIs in certain situations.
Electroencephalography (EEG) is the most popular non-invasive brain recording technique. It works by picking up weak electrical signals generated by neurons, which are then amplified and processed. EEG devices are also the easiest to use and most accessible. If you have ever seen or worn any of those brain-reading toys, then you have experienced EEG BCI in action. These devices are relatively affordable, costing from a couple of hundred dollars up to $1,000. The drawback of EEG BCIs is their low spatial resolution (they can read regions of the brain in 6-8 cm² patches). However, they offer good temporal resolution and allow the wearer to move freely.
Where EEG works by measuring neuron’s electrical signals, magnetoencephalography (MEG) works by measuring magnetic fields generated by neurons. MEG offers better spatial resolution than EEG. However, one of the main drawbacks of MEG is its high signal-to-noise ratio, several orders of magnitude higher than EEG. For MEG to work correctly, the device needs to be magnetically shielded to reduce the noise coming from background magnetic fields as much as possible. Kernel was experimenting with measuring magnetic fields generated by the brain with optically pumped magnetometers but it seems the company has switched their approach towards a combination of EEG and fNIRS.
fNIRS, short for functional near-infrared spectroscopy, is an optical method for measuring brain activity. It works by emitting near-infrared light (usually wavelengths between 650 to 900 nm) into the scalp. This light is then absorbed and scattered by haemoglobin, allowing a detector to infer the blood's oxygen level and, from there, infer neural activity, as active brain regions consume more oxygen. By detecting changes in these absorption patterns, fNIRS can deduce brain activity. In terms of spatial and temporal resolution, fNIRS is similar to EEG and also offers a high level of mobility.
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Invasive BCIs require open brain surgery to install electrodes which can be placed on the surface of the brain (a semi-invasive approach if they do not penetrate into the brain) or inserted deep into the brain.
The significant advantage of the invasive approach is a better signal-to-noise ratio compared to non-invasive methods. The electrodes are much closer to neurons and can record neural activity with much higher precision. However, implanting these devices often requires risky open-brain surgery. Additionally, there is a risk that the brain may reject the implant, leading to brain scars. There is also an increased risk of these implants damaging the brain, which can have severe consequences for the patient.
Invasive methods are more expensive, requiring not only carefully designed implants but also a skilled team of highly trained neurosurgeons and neurologists to implant them and manage their use. Neuralink tries to reduce the costs of implanting an invasive BCI by using a specialised robot to insert the electrodes into the brain. If successful, we might see more companies adopting robots instead of hiring neurosurgeons.
Electrocorticography (ECoG) involves placing electrodes on the surface of the brain, under the skull. ECoG provides higher spatial resolution and signal quality than non-invasive methods like EEG, with less noise and more stable recordings. It's used for applications requiring fine control, such as advanced prosthetics.
Microelectrode array (MEA)
Microelectrode array (MEA) consists of a grid of tiny electrodes that can be implanted directly into the brain or placed on the brain surface. MEAs enable the detection and measurement of electrical signals from multiple neurons simultaneously. Their high spatial and temporal resolution makes them particularly valuable for research and applications aiming to understand neural functioning or restore lost sensory or motor functions.
Deep-brain simulation involves implanting electrodes deep within the brain tissue to stimulate specific brain areas. While primarily used for therapeutic interventions (e.g., in Parkinson's disease), it also offers insights into deep brain activity that can be leveraged by BCIs for both recording and stimulation purposes.
Another approach is stent electrodes, pioneered by Synchron and their Stentrode. These devices are inserted into the brain without the need for open brain surgery. This is accomplished by inserting the device into the jugular vein in the neck and pushing it up a blood vessel to the motor cortex in the brain. When it reaches its destination, it unfolds like a flower in the blood vessel to not disrupt the blood flow and starts recording the electrical activity from the nearby neurons.
Once the Stentrode is in place, it is connected to a small antenna placed under the skin in the chest which then sends raw brain activity data wirelessly to an external device.
Stent electrodes are a new class of invasive BCI but they have already proven themselves to work. In 2022, a man with ALS was able to send text messages from his iPad thanks to Stentrode implanted in his brain. All that the man has to do is to think about tapping his foot and the system translates the brain activity picked up by the implant into cursor movements.
A new class of invasive BCI is neural lace, a thin and dense network of electrodes placed on the brain.
In 2022, Blackrock Neurotech revealed Neuralace, a next-generation BCI featuring an extremely flexible lace-structured chip designed to be placed on the brain's surface. The initial version of Neuralace will offer 10,000 channels for monitoring brain activity, with Blackrock indicating the potential for scale beyond this number in the future. The company expects to make Neuralace available to the neuroscience research community by 2024 and aims for the first-in-human demonstrations of a Neuralace visual prosthesis by 2028.
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Medical applications of BCIs
Now that we know what BCIs are, let's explore what we can do with them. We will start with medical applications, as most BCIs today are designed to help treat various disabilities and diseases.
Restoring the ability to communicate with the world
Some people suffer from locked-in syndrome, where they are fully conscious and mentally aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body, except for vertical eye movements and blinking.
Thanks to BCI technology, these individuals have an opportunity to communicate again or more easily with the people around them. Early versions worked by translating the patient's brain activity into movements of a cursor. After some training, the patient could move the cursor from one letter to another on a virtual keyboard using only their thoughts. Newer devices can directly translate brain activity into entire words or sentences.
BCI technology can help paralyzed individuals restore mobility by bypassing damaged nerves and directly stimulating the muscles. This was demonstrated by Gert-Jan Oskam, a 40-year-old man who, after being paralyzed in a cycling accident, was able to walk again last year thanks to BCI.
Another example is Ian Burkhart who in 2020, regained limited movement and a sense of touch through a BCI after a diving accident left him paralysed.
BCIs can also be used to control wheelchairs or even exoskeletons to restore mobility for paralysed patients. As an example of the latter, in 2014, a paraplegic man made the first kick of the World Cup in Brazil using a mind-controlled robotic exoskeleton.
One of the first examples of enabling control of a robotic arm through a BCI was in 2012. The patient has to think about using the robotic arm as if it were their own arm. The implant then translates the brain activity into movements of the robotic arm.
In 2021, a brain implant developed by Blackrock Neurotech enabled Nathan Copeland to not only control a prosthetic arm but also feel the robotic hand. The hand has a tactile sensor which stimulates Nathan’s brain to give him a sensation of touch. Thanks to that implant, Nathan had an opportunity to meet Barrack Obama and shake his hand with his robotic hand.
Treating neurological and mental diseases
Another interesting and promising application of BCIs in medicine is the treatment of neurological and mental diseases, such as Parkinson's disease or depression. The basic idea here is simple - use BCI to detect the symptoms and then stimulate the brain to counteract them.
This approach has been proven to successfully treat epilepsy and seizures. In one such study, researchers not only addressed seizures but also OCD with deep brain stimulation. Deep brain stimulation can also be used to help manage Parkinson's disease and chronic pain.
Brain implants have been proven to treat mental diseases, too. On at least two occasions that I am aware of, researchers helped treat severe cases of depression. In both cases, deep brain stimulation was the last hope as other treatments have not yielded positive results. The brain implants, however, worked and helped improve the quality of life for both patients. A similar approach might also be used to treat other mental diseases such as anxiety or panic attacks, and to treat addictions.
What else is possible with BCIs?
Recently, BCIs have been gaining more attention beyond medical applications. Some of the example applications I'm going to share are real, while others are more speculative. Feel free to share in the comments what other applications you think are possible.
New ways of communication between people
Direct brain-to-brain communication opens new ways of communication between people. It can enable not only sending messages using thoughts but also sharing experiences. Instead of describing how we felt, we can share what we felt, our emotions. Others then could see what we saw, feel what we touched, hear what we heard and smell what we smelled. They could fully immerse into what we experienced just like they were there. That could lead to the creation of new forms of entertainment. A good sci-fi example of that are braindances from Cyberpunk 2077, where the user can relive in fine detail what the person recording the braindance experienced.
New forms of entertainment
BCIs can also give rise to new forms of entertainment. I mentioned braindances and that is a form of entertainment that could emerge when BCIs are widely adopted and the technology advanced to provide two-way communication.
In the meantime, BCIs can be used to enhance entertainment. Video games could be a fertile ground for novel applications of BCIs due to their interactivity and high degree of immersion. Valve, for example, was interested in including some form of non-invasive BCI in their VR headsets to measure the emotional state of the players. That information could then be used by game developers to provide richer, more immersive games. Another example is Neurable, which in 2017 debuted a VR headset with non-invasive BCI to enable hands-free control in virtual worlds.
We also have seen simple EEG-based BCIs incorporated in toys, from cat ears that go up or down depending on the wearer’s mood to mind-controlled toys that let you pretend to be a Jedi.
Controlling exoskeletons and robots with thoughts
Being able to control computers with thoughts opens almost unlimited possibilities. Any device that can be controlled by a computer can then be controlled with thoughts. We could turn lights on and off or switch TV channels just by thinking about that. However, I think there are more interesting applications at the intersection of BCI and robotics.
We touched upon mind-controlled exoskeletons in medical applications of BCI. But rehabilitation is not the only application of exoskeletons. We see more and more exoskeletons designed not to restore mobility but to enhance it for healthy people. Adding BCI to these devices can make controlling them as natural as controlling our own bodies.
We can also apply BCIs to control a single robot or an entire swarm of robots. In the latter case, robots can act as an extension of our own bodies, venturing into environments that are too dangerous for us. It might even be possible to choose one robot to become our avatar for us to “be there” even if we are thousands of kilometres away.
When I was doing research for this article, I also found that researchers have successfully used BCI to control animals, effectively turning them into biorobots. In 2013, one group of researchers implanted a BCI into a rat’s brain through which a human wearing a non-invasive BCI could control the rat’s tail using their thoughts. Another group successfully controlled cockroaches using BCIs.
In 2019, the US military published a report titled Cyborg Soldier 2050 in which military experts explored what implication the human-machine fusion can have for the military. The study envisions a future in which soldiers are enhanced with various sensory augmentations as well as with “direct neural enhancement of the human brain”. These neural enhancements, achieved with BCI, will allow soldiers to not only better communicate with each other but also to control drones, exoskeletons, military robots and other remote weapon systems. For example, a fighter pilot could this way control a small fleet of aerial combat drones.
The authors of the report believe that by 2050, BCI technology will advance to the point in which it can raise the soldier’s situational awareness, improve reactions and increase the impact a soldier can have on the battlefield.
Militaries might also be interested in using BCIs to suppress soldiers’ fear or anxiety or to reduce the impact of PTSD on retired soldiers.
Improving human performance
BCIs could find use among top performers such as elite athletes and professional gamers, who are already at the pinnacle of their disciplines and are seeking anything that could give them even the slightest edge over competitors. One method of achieving this could be through neuropriming.
Neuropriming is a technique used to enhance the brain's ability to learn and perform by applying a mild electrical current to specific areas of the brain, typically through a non-invasive device using transcranial direct-current stimulation (tDCS). This stimulation is intended to increase neural plasticity, making the brain more receptive to training, and thus improving cognitive functions and physical skills more effectively.
In 2016, James Michael McAdoo of the Golden State Warriors tested Halo Neuroscience's headphones, designed to enhance athletic performance through neuropriming. Additionally, several athletes competing in the 2016 Olympic Games in Rio were using Halo’s device.
The results, however, have been mixed. One group of researchers found no effect of neuropriming on amateur athletes. Jeff Bercovici shared on Men's Health his experience with Halo devices and also hasn’t found strong evidence that the device improved his performance. However, the US Ski and Snowboard Association found in 2016 that Halo headphones worked.
Nevertheless, if researchers can find a way to use BCIs to improve mental and physical performance not only for top performers but also for the general population, then there could be a compelling case for adopting BCI technology.
One of the earliest examples of BCI was the 1965 piece Music for Solo Performer by the American composer Alvin Lucier. The piece makes use of EEG and analogue signal processing hardware (filters, amplifiers, and a mixing board) to stimulate acoustic percussion instruments. To perform the piece one must produce alpha waves and thereby "play" the various percussion instruments via loudspeakers which are placed near or directly on the instruments themselves. A modern successor to Music for Solo Performer is BrainiBeats, in which two people with non-invasive BCIs played music together using only their thoughts.
Artists using BCIs could discover new ways of expressing themselves through music, paintings, writing, movies, or something entirely novel. BCIs can also simplify the process of expressing ourselves through art. If you have a song or a picture in your head but lack the skills to fully articulate it, a BCI could extract it and bring it into the world.
Thanks to BCIs, creative designers can introduce new functionalities to clothing, such as expressing the wearer's mood through lights or using BCI as a switch to activate various effects. A good example here is the Pangolin Scales Dress which combines fashion with non-invasive BCI.
One creative application of BCi that is close to my heart is in cosplay. Some cosplayers integrate simple off-the-shelf non-invasive BCI modules into their costumes to, for example, spread the wings or open the helmet without pushing any buttons. I myself have designed two costumes that will use BCI (all I need now is time to complete them).
Merging humans with AI
When Elon Musk announced Neuralink, he mentioned that one of the reasons for founding the company was to provide a way of merging humans with AI. This idea has been explored multiple times before in science fiction and inside transhumanist circles. The concept is simple - imagine you have ChatGPT in your head and instead of going to the website or app, you just mentally ask the question and immediately know the answer. You might even “subconsciously” know the answer before you ask the question.
Some see merging this way with AI as a way of unlocking full human potential. Others see it as the only way to ensure humanity’s survival in the age of superintelligent AIs.
The long path towards mainstream BCIs
Brain-computer interfaces have proven useful in treating various disabilities and diseases. They have also shown potential beyond medical applications, from changing how we communicate and control machines to enabling us to better express ourselves. However, the path from where these devices are now to where they can be or what they are promised to achieve is long. It will take many years and many breakthroughs to realise the dream of mass adoption of BCIs.
Currently, BCIs are useful mostly in medical studies and as a subject of research projects. If we want BCIs to become widespread, then these devices have to become safer and have a clearly defined value proposition. Consumer BCIs also need to look good. Many people will likely hesitate to use one if it involves having a USB port sticking out of their head or if they have to wear an unattractive cap or helmet. Google Glass has shown how easy is to mess up this aspect of wearable tech and make its users a target for jokes and mockery. Ideally, BCIs would be invisible from the outside and discreet. Perhaps we will see some innovative designs, like embedding electrodes into headphones or stylish headbands.
BCI is an exciting technology with huge potential to change our relationship with technology and how we communicate with each other. However, there are still many problems and issues to be solved before BCIs can become as ubiquitous as smartphones are today. Chief among them are the questions around safety, privacy and maintaining these devices once they are on or inside our heads. This is a big topic and we will discuss it in detail in part three of the series.
Other articles in the Brain-Computer Interfaces series
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