In both science and science fiction, the pinnacle of human evolution is a brain that connects directly to a computer.
We’re not quite there yet, though scientists have made significant headway in using chips implanted in human brains, known as brain-machine interfaces, as the neural equivalent of a prosthetic limb, targeting damaged areas of the brain to achieve things like restoring mobility to patients who are paralyzed. A significant hitch is that implanting such devices is the brain is incredibly risky. But now scientists at DARPA, the Department of Defense’s research arm, have pioneered a method of chip implantation that’s less invasive—and that could lead to an expansion of the use of brain-machine interfaces.
In an article published Monday in Nature Biotechnology, researchers at the University of Melbourne working under DARPA’s Reliable Neural-Interface Technology (RE-NET) program describe a study in sheep that recorded signals from the motor cortex of the brain (which controls movement) using a new device they’ve dubbed the “stentrode.” The stentrode can be implanted into the brain through blood vessels without even opening the skull, eliminating the need for the sort of invasive surgery required to implant traditional electrode arrays.
Instead, researchers insert the device via a blood vessel in the neck, then guide it to the appropriate location in the brain using real-time imaging. Once in place, the device expands and attaches to the walls of the blood vessel to read the activity of nearby neurons. In past studies, DARPA and other scientists have successfully demonstrated that paralyzed patients outfitted with electrode array brain implants that intercepted the brain’s electrical signals in a similar way could move prosthetic limbs.
Researchers are planning a human trial of the stentrode next year. If it’s successful, it could be a very big deal, effectively eliminating the biggest risk in implanting brain-machine interfaces, which is open brain surgery.
A recent Wired profile of neurologist Phil Kennedy, a pioneer in the realm of brain machine interfaces, revealed just how dangerous implanting the devices can be. Kennedy, eager to test his device on a healthy brain, flew to Belize to have his own device implanted in himself. Due to swelling in his brain, his recovery at first went poorly, rendering him unable to really speak for days. And after just 88 days, he had to have his bulky implant removed.
Kennedy envisions a future in which brain chips will be a normal thing for all humans. He told Wired:
“The first goal is to get the speech restored. The second goal is to restore movement, and a lot of people are working on that—that’ll happen, they just need better electrodes. And the third goal would then be to start enhancing normal humans.”
Eventually, Kennedy said, we’re all going to “extract our brains and connect them to small computers that will do everything for us, and the brains will live on.”
DARPA is also exploring using brain chips to treat PTSD and to help soldiers returning from war with traumatic brain injuries impacting memory. In other instances, DARPA’s ambitions for neural prosthetics veer a little more toward sci-fi, like, as Annie Jacobsen describes in her recent history of DARPA, using implants to allow soldiers on the battlefield to communicate by thought alone.
But, as Wired’s profile of Kennedy points out, invasive brain implants are also going out of style. Instead, research has begun favoring electrocorticography, which involves laying a flat surface of electronics on top of the brain to capture less detailed information than invasive implants might. DARPA’s new method, if successful, could offer a third option: a way of measuring detailed signals without having to open up the skull at all. And that will make us all one step closer to living on forever as disembodied brains in a vat.