Silicon Valley's race to develop a brain-computer interface

Entrepreneur Bryan Johnson says he wanted to become very rich in order to do something great for humankind. Last year Johnson, founder of the online payments company Braintree, starting making news when he threw $100 million behind Kernel, a startup he founded to enhance human intelligence by developing brain implants capable of linking people's thoughts to computers. Johnson isn't alone in believing that "neurotechnology" could be the next big thing. To many in Silicon Valley, the brain looks like an unconquered frontier whose importance dwarfs any achievement made in computing or the Web. According to neuroscientists, several figures from the tech sector are currently scouring labs across the U.S. for technology that might fuse human and artificial intelligence.