Elon Musk said on Wednesday he expects a wireless brain chip developed by his company Neuralink to begin human clinical trials in six months, after the company missed earlier timelines set by him.

The company is developing brain chip interfaces that it says could enable disabled patients to move and communicate again, with Musk adding on Wednesday that it will also target restoring vision.

Based in the San Francisco Bay Area and Austin, Texas, Neuralink has in recent years been conducting tests on animals as it seeks approval from the US Food and Drug Administration (FDA) to begin clinical trials in people.

“We want to be extremely careful and certain that it will work well before putting a device into a human,” Musk said during a much-awaited public update on the device.

Speaking to a crowd of select invitees in a presentation at Neuralink headquarters that lasted nearly three hours, Musk emphasized the speed at which the company is developing its device.

“The progress at first, particularly as it applies to humans, will seem perhaps agonizingly slow, but we are doing all of the things to bring it to scale in parallel,” he added. “So, in theory, progress should be exponential.”

The FDA did not immediately reply to a Reuters’ request for comment. The first two human applications targeted by the Neuralink device will be in restoring vision and enabling movement of muscles in people who cannot do so, Musk said.

“Even if someone has never had vision, ever, like they were born blind, we believe we can still restore vision,” he said. The event was originally planned for Oct. 31 but Musk postponed it just days before without giving a reason.

Neuralink’s last public presentation, more than a year ago, involved a monkey with a brain chip that played a computer game by thinking alone.

Musk, who also runs electric vehicle manufacturer Tesla , rocket firm SpaceX, and social media platform Twitter, is known for lofty goals such as colonizing Mars and saving humanity.

His ambitions for Neuralink, which he launched in 2016, are of the same grand scale.

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He wants to develop a chip that would allow the brain to control complex electronic devices and eventually allow people with paralysis to regain motor function and treat brain diseases such as Parkinson’s, dementia and Alzheimer’s.

He also talks of melding the brain with artificial intelligence. Neuralink, however, is running behind schedule.

Musk said in a 2019 presentation he was aiming to receive regulatory approval by the end of 2020.

He then said at a conference in late 2021 that he hoped to start human trials this year.

Neuralink has repeatedly missed internal deadlines to gain FDA approval to start human trials, current and former employees have said.

Musk approached competitor Synchron earlier this year about a potential investment after he expressed frustration to Neuralink employees about their slow progress, Reuters reported in August.

Synchron crossed a major milestone in July by implanting its device in a patient in the United States for the first time.

It received US regulatory clearance for human trials in 2021 and has completed studies in four people in Australia.