Elon Musk’s brain tech startup Neuralink has closed a $650 million funding round, the company announced on Monday.

ARK Invest, Founders Fund, Sequoia Capital, Thrive Capital, Lightspeed Venture Partners and other firms participated in the round, according to a release. Neuralink said the fresh capital will help the company bring its technology to more patients and develop new devices that “deepen the connection between biological and artificial intelligence.”

Neuralink is building a brain-computer interface, or a BCI, which is a system that translates brain signals into commands for external technologies.

The company’s first system, called Telepathy, involves 64 “threads” that are inserted directly into the brain. The threads are thinner than a human hair and record neural signals through 1,024 electrodes, according to Neuralink’s website.

The initial aim of the technology is to help patients with severe paralysis restore some independence. As of Monday, five patients have been implanted with Neuralink’s technology, and are able to “control digital and physical devices with their thoughts,” the release said.

Neuralink is currently carrying out four separate clinical trials around its Telepathy system.

BCIs have been studied in academia for decades, and several other companies including Synchron, Paradromics and Precision Neuroscience are developing their own systems. 

Paradromics on Monday announced it successfully implanted its BCI in a human for the first time.  

It’s not exactly clear what devices Neuralink will look to develop next, but Musk has for years espoused grand ambitions for the brain tech startup. He has even claimed that he would be willing to get an implant himself.

One of the capabilities Musk has repeatedly highlighted is the ability to restore vision to blind patients.

Neuralink received a “Breakthrough Device” designation from the U.S. Food and Drug Administration for a device called Blindsight. This designation is granted to medical devices that have the potential to provide improved treatment for debilitating or life-threatening conditions.

In a post on his social media platform X in September, Musk said Blindsight will enable even those who have lost both eyes and their optic nerve to see.

Neuralink still has a long road ahead before it can commercialize these technologies.

WATCH: Neuralink shares video of patient playing chess using signals from brain implant