Doctors call this mild cognitive impairment, and it affects most people as they get older. Certain types of PET scans can reveal signs of both these conditions and can therefore be used to spot people with mild cognitive impairment who are most at risk of developing Alzheimer's. This data set consists of brain images of 182 people in their 70s with normal brains and brain images of 139 people of roughly the same age who have been diagnosed with Alzheimer's. Hongyoon and Kyong say their neural network identified those at risk of developing Alzheimer's with an accuracy of 81 percent.

Like many in Silicon Valley, technology entrepreneur Bryan Johnson sees a future in which intelligent machines can do things like drive cars on their own and anticipate our needs before we ask. What's uncommon is how Johnson wants to respond: find a way to supercharge the human brain so that we can keep up with the machines. From an unassuming office in Venice Beach, his science-fiction-meets-science start-up, Kernel, is building a tiny chip that can be implanted in the brain to help people suffering from neurological damage caused by strokes, Alzheimer's or concussions. Top neuroscientists who are building the chip -- they call it a neuroprosthetic -- hope that in the longer term, it will be able to boost intelligence, memory and other cognitive tasks. The medical device is years in the making, Johnson acknowledges, but he can afford the time.