The brain is inarguably the most complex and mysterious organ in the human body.
As the epicenter of intelligence, mastermind of movement, and song for our senses, the brain is more than a 3-lb organ encased in shell and fluid. Rather, it is the crown jewel that defines the self and, broadly, humanity.
For decades now, researchers have been exploring the potential for connecting our own astounding biological “computer” with actual physical mainframes. These so-called “brain-computer interfaces” (BCIs) are showing promise in treating an array of conditions, including paralysis, deafness, stroke, and even psychiatric disorders.
Among the big players in this area of research is billionaire entrepreneur Elon Musk, who in 2016 founded Neuralink. The company’s short-term mission is to develop a brain-to-machine interface to help people with neurologic conditions (eg, Parkinson’s disease). The long-term mission is to steer humanity into the era of “superhuman cognition.”
But first, some neuroscience 101.
Neurons are specialized cells that transmit and receive information. The basic structure of a neuron includes the dendrite, soma, and axon. The dendrite is the signal receiver. The soma is the cell body that is connected to the dendrites and serves as a structure to pass signals. The axon, also known as the nerve fiber, transmits the signal away from the soma.
Neurons communicate with each other at the synapse (ie, axon-dendrite connection). Neurons send information to each other through action potentials. An action potential may be defined as an electric impulse that transmits down the axon, causing the release of neurotransmitters, which may consequently either inhibit or excite the next neuron (leading to the initiation of another action potential).
So how will the company and other BCI companies tap into this evolutionarily ancient system to develop an implant that will obtain and decode information output from the brain?
The Neuralink implant is composed of three parts: The Link, neural threads, and the charger.
A robotic system, controlled by a neurosurgeon, will place an implant into the brain. The Link is the central component. It processes and transmits neural signals. The micron-scale neural threads are connected to the Link and other areas of the brain. The threads also contain electrodes, which are responsible for detecting neural signals. The charger ensures the battery is charged via wireless connection.
The invasive nature of this implant allows for precise readouts of electric outputs from the brain ― unlike noninvasive devices, which are less sensitive and specific. Additionally, owing to its small size, engineers and neurosurgeons can implant the device in very specific brain regions as well as customize electrode distribution.
The Neuralink implant would be paired with an application via Bluetooth connection. The goal is to enable someone with the implant to control their device or computer by simply thinking. The application offers several exercises to help guide and train individuals on how to use the implant for its intended purpose. This technology would allow people with neurologic difficulties (eg, paralysis) to communicate more easily through text or speech synthesis, as well as partake in creative activities such as photography.
Existing text and speech synthesis technology are already underway. For example, Synchron, a BCI platform company, is investigating the use of Stentrode for people with severe paralysis. This neuroprosthesis was designed to help people associate thought with movement through Bluetooth technology (eg, texting, emailing, shopping, online banking). Preliminary results from a study in which the device was used for patients with amyotrophic lateral sclerosis showed improvements in functional independence via direct thinking.
Software intended to enable high-performance handwriting utilizing BCI technology is being developed by Francis R. Willet, PhD, at Stanford University. The technology has also shown promise.
“We’ve learned that the brain retains its ability to prescribe fine movements a full decade after the body has lost its ability to execute those movements,” says Willet, who recently reported on results from a BCI study of handwriting conversion in an individual with full-body paralysis. Through a recurrent neural networking decoding approach, the BrainGate study participant was able to type 90 characters per minute ― with an impressive 94.1% raw accuracy ― using thoughts alone.
Although not a fully implantable brain device, this percutaneous implant has also been studied of its capacity to restore arm function among individuals who suffered from chronic stroke. Preliminary results from the Cortimo trials, led by Mijail D. Serruya, MD, an assistant professor at Thomas Jefferson University, have been positive. Researchers implanted microelectrode arrays to decode brain signals and power motor function in a participant who had experienced a stroke 2 years earlier. The participant was able to use a powered arm brace on their paralyzed arm.
Neuralink recently released a video demonstrating the use of the interface in a monkey named Pager as it played a game with a joystick. Company researchers inserted a 1024 electrode neural recording and data transmission device called the N1 Link into the left and right motor cortices. Using the implant, neural activity was sent to a decoder algorithm. Throughout the process, the decoder algorithm was refined and calibrated. After a few minutes, Pager was able to control the cursor on the screen using his mind instead of the joystick.
Musk hopes to develop Neuralink further to change not only the way we treat neurological disorders but also the way we interact with ourselves and our environment. It’s a lofty goal to be sure, but one that doesn’t seem outside the realm of possibility in the near future.
Known Unknowns: The Ethical Dilemmas
One major conundrum facing the future of BCI technology is that researchers don’t fully understand the science regarding how brain signaling, artificial intelligence (AI) software, and prostheses interact. Although offloading computations improves the predictive nature of AI algorithms, there are concerns of identity and personal agency.
How do we know that an action is truly the result of one’s own thinking or, rather, the outcome of AI software? In this context, the autocorrect function while typing can be incredibly useful when we’re in a pinch for time, when we’re using one hand to type, or because of ease. However, it’s also easy to create and send out unintended or inappropriate messages.
These algorithms are designed to learn from our behavior and anticipate our next move. However, a question arises as to whether we are the authors of our own thoughts or whether we are simply the device that delivers messages under the control of external forces.
“People may question whether new personality changes they experience are truly representative of themselves or whether they are now a product of the implant (eg, ‘Is that really me?’; ‘Have I grown as a person, or is it the technology?’). This then raises questions about agency and who we are as people,” says Kerry Bowman, PhD, a clinical bioethicist and assistant professor at the Temerty Faculty of Medicine of the University of Toronto.
It’s important to have safeguards in place to ensure the privacy of our thoughts. In an age where data is currency, it’s crucial to establish boundaries to preserve our autonomy and prevent exploitation (eg, by private companies or hackers). Although Neuralink and BCIs generally are certainly pushing the boundaries of neural engineering in profound ways, it’s important to note the biological and ethical implications of this technology.
As Bowman points out, “Throughout the entire human story, under the worst of human circumstances, such as captivity and torture, the one safe ground and place for all people has been the privacy of one’s own mind. No one could ever interfere, take away, or be aware of those thoughts. However, this technology challenges one’s own privacy ― that this technology (and, by extension, a company) could be aware of those thoughts.”
Leanna M. W. Lui, HBSc, is an MSc candidate at the University of Toronto in the Mood Disorders Psychopharmacology Unit.
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