This as-told-to essay is based on a conversation with Matthew Willsey, a neurosurgeon who specializes in brain-computer interfaces. It has been edited for length and clarity.
Before I became a neurosurgeon, I was an electrical engineer.
I graduated from MIT with my undergraduate degree and pursued my master’s in electrical engineering. I did my thesis with Alan Oppenheim, a professor who helped pioneer the field of digital signal processing.
Signal processing looks at how to extract information from signals. In many ways, that’s similar to what we do with brain-computer interfaces (BCIs).
Around 2009, I saw a video of someone controlling a computer cursor or robotic arm with electrodes implanted into their brain, and I remember thinking, “That is the coolest thing I’ve ever seen in my life.”
That was the epiphany moment for me.
I soon shadowed a neurosurgeon in Texas. The combination of seeing BCIs and then seeing surgery convinced me that neurosurgery was the right career path.
I went to school at Baylor College of Medicine, then matched into a neurosurgery residency at the University of Michigan. I spent three years doing research and completed a Ph.D., focused on BCIs.
Today, my practice is in functional neurosurgery, with a specialty in deep brain stimulation and epilepsy. I also have a research lab that studies BCIs.
There are diseases and injuries in which the brain is largely functioning fine. People know how they want to move or what they want to say, but the pathway connecting the brain to the body or the mouth is interrupted or degraded.
Someone with ALS, for example, knows what words they want to say, but they can’t produce speech.
A BCI tries to record brain activity, recognize patterns, and figure out what someone intends to do. Then, you can put text on a screen or provide a control signal to a robotic arm or a computer cursor.
The Paradromics system is designed to be fully implantable. A lot of the BCIs used in research labs before were implanted into the brain, but they had a connection that passed through the skin, so they could connect to a computer.
If you want to build these devices at scale, ideally, you want fully implantable systems. People don’t want to be tethered to a computer.
The procedure should be repeatable
This process is built on careful patient selection. You want someone who has enough impairment that they could benefit, but not so much impairment that it makes surgery unsafe.
For the surgery, we started with the cranial portion. We made an incision, took the bone off, opened the dura — the lining around the brain — and exposed the cortex.
With our navigational system, our own sight, and preoperative imaging, we can identify the exact location where we want to place the array or implant.
The array is gently placed onto the brain and then inserted into the cortex. After we secured the lead, closed the dura, and put the bone back in place, we made an incision in the chest for the transceiver. An extension lead runs under the skin from the brain component down to the chest component.
Before leaving the operating room, you want to know that the electrodes are in the brain, bleeding has stopped, the tissues are closed appropriately, and the whole system is communicating.
The procedure itself takes about four hours.
The operation is not that technically different from a surgical standpoint. Neurosurgeons know how to perform a craniotomy and access the brain. If you want to scale BCI technology, you want neurosurgeons to be able to pick it up very easily.
The hope is that, as we perform these procedures, they become routine.
This surgery takes the next step forward
A lot of the surgery felt like business as usual.
There were times when you would take a step back, when you’re placing the array over the cortex, and think: Okay, here we go. This will be a major step forward if we can get everything working correctly.
Then you have to get back into the zone.
Fundamentally, every surgeon is mostly focused on patient safety. Once the patient wakes up, you do the postoperative exam. When the patient is doing well, then you can really take a step back and say, “Wow, I can’t believe we’re at this point now where we have somebody implanted with a novel brain-computer interface.”
It was really remarkable to be part of a team that essentially takes that next step forward.
One of the main reasons I got into medicine was to have the opportunity to help bring these new therapies to the people who needed them.
To have the chance to do that was very fulfilling.
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