Neuralink's first human patient has been revealed. Here's how we got here.

• Neuralink is one of Elon Musk's strange and futuristic companies.
• It's developing neural-interface technology — aka putting microchips in people's brains.
• Neuralink's first human patient can control a computer mouse using their thoughts, Musk says.

Elon Musk is known for his high-profile companies like Tesla and SpaceX, but the billionaire also has a handful of unusual ventures. He said he started one of them to achieve "symbiosis" between the human brain and artificial intelligence.