The process, described in an unpublished academic paper, is an important step toward a potential system to plug human brains directly into computers.
The paper's five authors have been employed by or loosely associated with Neuralink, a small and secretive brain computing start-up founded by Musk, according to people familiar with their work and public information.
Some of the research pre-dates the formation of the company, and there is no mention of the scientists’ affiliation with the billionaire in the paper, which was posted last month to an online repository for academics and hasn't been previously reported.
The authors dub their system a “sewing machine” for the brain. It involves scientists in a laboratory removing a piece of a rat's skull and inserting a single needle that sends flexible electrodes into brain tissue.
The researchers are soliciting feedback on their work before submitting it for peer review and publication in a scientific journal. The authors and a spokesperson for Neuralink either declined to comment or didn’t respond to requests.
Still years away from possible human testing, the paper shows a path forward to monitoring - and potentially stimulating - brain activity with minimal cranial harm.
That could enable a company like Neuralink to one day build a device with artificial intelligence that people could access with their thoughts. Still, such a business may find it difficult to locate customers willing to undergo surgery to remove a chunk of their skulls. To start, the science community sees promise in a version of the technology that could treat patients with Parkinson’s disease, memory loss or other ailments of the brain.
The US Defense Advanced Research Projects Agency provided financial support for the research. The agency, Darpa, is known for its role in forming the internet and GPS. For the rat-brain project, Darpa awarded $2.1 million (R29.38m) to the University of California at San Francisco, where the bulk of the work was done in conjunction with a lab at Berkeley.
Scientists have been working for years on ways to place electrodes in the brain while causing as little damage or inflammation as possible.
One major challenge is crafting highly flexible electrodes that can move with the brain but are rigid enough to be inserted in just the right spot.
Mackenzie Mathis, a researcher who studies rodents at Harvard University’s Rowland Institute, compares the problem to injecting cooked spaghetti into Jello. The new study is “a big step in the right direction,” said Mathis.
The sewing machine employs a novel technique to solve that challenge. It uses a stiff needle to insert a bendable and thin polymer electrode, just a few millimetres in length, deep into the brain. The machine injects an electrode every few seconds, much faster than alternative methods. Attached is a small circuit board, which sits on the back of the rat's head and records signals from the brain.
In the paper, scientists detailed their work with adult, male, Long-Evans rats, a common test subject in labs. In one case, a rat with two dozen implanted electrodes was monitored for two months. Other rats’ implants didn’t last as long.
There are other drawbacks. Electrodes from the sewing machine aren’t as thin as those used in experiments by other labs, the researchers wrote. The thinner they are, the harder it is to get them into place.