Neuralink is pursuing what Elon Musk calls ‘neural lace’ technology, implanting tiny brain electrodes that may one day upload and download thoughts.

Building a mass-market electric vehicle and colonizing Mars aren’t ambitious enough for Elon Musk. The billionaire entrepreneur now wants to merge computers with human brains to help people keep up with machines.

The founder and chief executive of Tesla Inc. and Space Exploration Technologies Corp. has launched another company called Neuralink Corp., according to people familiar with the matter. Neuralink is pursuing what Mr. Musk calls “neural lace” technology, implanting tiny brain electrodes that may one day upload and download thoughts.

Mr. Musk has taken an active role setting up the California-based company and may play a significant leadership role, according to people briefed on Neuralink’s plans, a bold step for a father of five who already runs two technologically complex businesses.

Mr. Musk didn’t respond to a request for comment. Max Hodak, who said he is a “member of the founding team,” confirmed the company’s existence and Mr. Musk’s involvement. He described the company as “embryonic” and said plans are still in flux but declined to provide additional details. Mr. Hodak previously founded Transcriptic, a startup that provides robotic lab services accessible over the internet.

Mr. Musk, 45 years old, is part businessman, part futurist. He splits his time between Tesla, which is under pressure to deliver its $35,000 Model 3 sedan on time, and SpaceX, which aims to launch a satellite-internet business and a rocket that can bring humans to Mars. He is also pushing development of a super high-speed train called Hyperloop.

Somewhere in his packed schedule, he has found time to start a neuroscience company that plans to develop cranial computers, most likely to treat intractable brain diseases first, but later to help humanity avoid subjugation at the hands of intelligent machines.

“If you assume any rate of advancement in [artificial intelligence], we will be left behind by a lot,” he said at a conference last June.

The solution he proposed was a “direct cortical interface”—essentially a layer of artificial intelligence inside the brain—that could enable humans to reach higher levels of function.

Mr. Musk has teased that he is developing the technology himself. “Making progress [on neural lace],” he tweeted last August, “maybe something to announce in a few months.” In January he tweeted that an announcement might be coming shortly.

He hasn’t made an official announcement, but Neuralink registered in California as a “medical research” company last July.

Mr. Musk has discussed financing Neuralink primarily himself, including with capital borrowed against equity in his other companies, according to a person briefed on the plans.

Neuralink has also discussed a possible investment from Founders Fund, the venture firm started by Peter Thiel, with whom Mr. Musk co-founded payments company PayPal, according to people familiar with the matter.

In recent weeks, Neuralink hired leading academics in the field, according to another person familiar with the matter. They include Vanessa Tolosa, an engineer at the Lawrence Livermore National Laboratory and an expert in flexible electrodes; Philip Sabes, a professor at the University of California in San Francisco, who studies how the brain controls movement; and Timothy Gardner, a professor at Boston University who is known for implanting tiny electrodes in the brains of finches to study how the birds sing.

Reached by phone, Dr. Gardner confirmed he is working for Neuralink, but declined to elaborate on its plans. Dr. Sabes declined to comment. Dr. Tolosa didn’t respond to a request for comment.

It is unclear what sorts of products Neuralink might create, but people who have had discussions with the company describe a strategy similar to SpaceX and Tesla, where Mr. Musk developed new rocket and electric-car technologies, proved they work, and is now using them to pursue more ambitious projects.

These people say the first products could be advanced implants to treat intractable brain disorders like epilepsy or major depression, a market worth billions of dollars. Such implants would build on simpler electrodes already used to treat brain disorders like Parkinson’s disease.

If Neuralink can prove the safety and efficacy of technology it develops and receive government approval, perhaps it then could move on to cosmetic brain surgeries to enhance cognitive function, these people say. Mr. Musk alluded to this possibility in his comments last June, describing how humans struggle to process and generate information as quickly as they absorb it.

“Your output level is so low, particularly on a phone, your two thumbs just tapping away,” he said. “This is ridiculously slow. Our input is much better because we have a high bandwidth visual interface into the brain. Our eyes take in a lot of data.”

Others pursuing the idea include Bryan Johnson, the founder of online payments company Braintree, who plans to pump $100 million into a startup called Kernel, which has 20 people and is pursuing a similar mission.

Mr. Johnson said he has spoken to Mr. Musk and that both companies want to build better neural interfaces, first to attack big diseases, and then to expand human potential.

Facebook Inc. has posted job ads for “brain-computer interface engineers” and other neuroscientists at its new secret projects division. And the Defense Advanced Research Projects Agency is investing $60 million over four years to develop implantable neural interface technology.

The technology faces several barriers. Scientists must find a safe, minimally invasive way to implant the electrodes, and a way to keep them stable in the brain. It also isn’t yet possible to record the activity of millions of the brain’s neurons to decode complex decisions, or distinguish when someone wants to eat a bowl of spaghetti or go to the bathroom.

Then there is persuading people to get elective brain surgery.

In comments published by Vanity Fair on Sunday, Mr. Musk said “for a meaningful partial-brain interface, I think we’re roughly four or five years away.”

If Mr. Musk indeed takes an active leadership role at Neuralink, that would raise more questions about his own personal bandwidth.

Tesla is building the largest battery factory on the planet to supply its forthcoming Model 3 electric vehicle, and it will need to produce hundreds of thousands of cars to meet its goal and justify its lofty market capitalization, which is approaching that of Ford Motor Co.
SpaceX has struggled to launch rockets fast enough to send satellites into orbit for its customers. Ultimately it wants to launch an internet-access business powered by more than 4,000 low-earth orbiting satellites, ferry space tourists to the moon and then bring astronauts to Mars.

Even so, Mr. Musk has proved many naysayers wrong. Traditional auto makers said he could never sell a popular electric car. Military-industrial graybeards scoffed at the idea he could even launch a rocket.