Elon Musk’s controversial startup Neuralink has implanted a chip in a human brain for the first time, the billionaire said in a post on his X platform late Monday.

The operation took place on Sunday and the patient was recovering well, he added.

Musk’s announcement could mark an important milestone for Neuralink’s efforts to usher potentially life-transforming technology out of the lab and into the real world. But he offered few details, and it’s unclear from Musk’s post how significant of a scientific advancement the implantation represents.

The company had received approval to study the safety and functionality of its chip implant and surgical tools.

“Initial results show promising neuron spike detection,” the world’s richest man and Neuralink founder said on X, the social media platform he owns.

Neuralink’s first product would be called Telepathy, he said in another post, adding that its initial users will be people who have lost the use of their limbs.

“Imagine if Stephen Hawking could communicate faster than a speed typist or auctioneer. That is the goal,” he wrote.

Neuralink has been working toward using implants to connect the human brain to a computer for half a decade, but the company faced scrutiny after a monkey died in 2022 during an attempt to get the animal to play Pong, one of the first video games. In December 2022, employees told Reuters that the company was rushing to market, resulting in careless animal deaths and a federal investigation.

In May last year, Neuralink received FDA clearance for human clinical trials, and a few months later, the startup began recruiting patients with quadriplegia caused by cervical spinal cord injury or amyotrophic lateral sclerosis (ALS).

The trial is part of what Neuralink is calling its “PRIME Study,” short for “Precise Robotically Implanted Brain-Computer Interface,” which aims to study the safety of its implant and surgical robot, and to test the functionality of its device, the company said in a September blog post about recruiting trial participants.

Trial patients will have a chip surgically placed in the part of the brain that controls the intention to move. The chip, installed by a robot, will then record and send brain signals to an app, with the initial goal being “to grant people the ability to control a computer cursor or keyboard using their thoughts alone,” the company wrote in September.

Neuralink did not respond to CNN’s request for further details.

Before Neuralink’s brain implants hit the broader market, they’ll need regulatory approval. The FDA put out a paper in 2021 mapping out the agency’s initial thoughts on brain-computer interface devices, noting the field is “progressing rapidly.”

While Neuralink and Musk have received significant attention for their attempts at a brain-computer interface, a number of other companies have also been working in this space, including a company called Synchron, the first company to gain FDA clearance to test a device in humans in 2021. Synchon has since been enrolling and implanting patients in a trial.

“The idea of brain-nervous system interfaces has great potential to help people with neurological disorders in future,” Tara Spires-Jones, president of the British Neuroscience Association, told the UK-based Science Media Center Tuesday. “However, most of these interfaces require invasive neurosurgery and are still in experimental stages thus it will likely be many years before they are commonly available.”