In the first years of her career in brain research, Beth Stevens thought of microglia with annoyance if she thought of them at all. When she gazed into a microscope and saw these ubiquitous cells with their spidery tentacles, she did what most neuroscientists had been doing for generations: she looked right past them and focused on the rest of the brain tissue, just as you might look through specks of dirt on a windshield. "What are they doing there?" she thought. Stevens never would have guessed that just a few years later, she would be running a laboratory at Harvard and Boston's Children's Hospital devoted to the study of these obscure little clumps. Or that she would be arguing in the world's top scientific journals that microglia might hold the key to understanding not just normal brain development but also what causes Alzheimer's, Huntington's, autism, schizophrenia, and other intractable brain disorders. Microglia are part of a larger class of cells--known collectively as glia--that carry out an array of functions in the brain, guiding its development and serving as its immune system by gobbling up diseased or damaged cells and carting away debris.

It doesn't look like a place to make groundbreaking discoveries that change the trajectory of society. But in these simulated, claustrophobic corridors, Demis Hassabis thinks he can lay the foundations for software that's smart enough to solve humanity's biggest problems. "Our goal's very big," says Hassabis, whose level-headed manner can mask the audacity of his ideas. He leads a team of roughly 200 computer scientists and neuroscientists at Google's DeepMind, the London-based group behind the AlphaGo software that defeated the world champion at Go in a five-game series earlier this month, setting a milestone in computing. It's supposed to be just an early checkpoint in an effort Hassabis describes as the Apollo program of artificial intelligence, aimed at "solving intelligence, and then using that to solve everything else."

Delivery by drone may be legal within two years. Just don't expect many pizzas or packages to wing their way through your neighborhood by then. Despite huge interest in unmanned aerial vehicles (UAVs), and considerable hype around the idea of using them to deliver goods, experts say significant challenges still need to be solved for drone delivery to get off the ground. Google and Amazon are leading the development of delivery drones, while UPS, FedEx, and a host of startups are also researching the technology. Earlier this month, the U.S. Senate Transportation Committee drafted a bill that paves the way for regulation of delivery drones within two years.

For Robert Welborn, head of data science for the insurer and finance company USAA, 2015 was the year machine learning started to make commercial sense. Access to improved machine-learning tools, cheaper processing technology, and a sharp decline in the cost of storing data were key. When those developments were combined with USAA's abundance of data, a technology studied for decades suddenly seemed practical. Insurance, finance, manufacturing, oil and gas, auto manufacturing, health care: these may not be the industries that first spring to mind when you think of artificial intelligence. But as technology companies like Google and Baidu build labs and pioneer advances in the field, a broader group of industries are beginning to investigate how AI can work for them, too.

Walking around my office on a recent morning, a female voice on my iPhone narrated the objects I passed. "Brick," "wall," "telephone," she said matter-of-factly. The voice paused when I came upon a bike hung on a wall-mounted rack, then intoned, "bicycle." The voice is part of a free image-recognition app called Aipoly that's trying to make it easier for those with vision impairments to recognize their surroundings. To use it, you point the phone's rear camera at whatever you want it to identify, and Aipoly will speak what it sees (or, at least, what it thinks it sees) and show the object's name on the phone's display.

Dan Chao is an avid cyclist who likes to train on a stationary bike. Lately while training he's been sporting a pair of trendy-looking headphones that also stimulate his brain. And he says the device has helped him improve his performance on his real bike. Chao is a cofounder and the CEO of a startup called Halo Neuroscience, which released the neurostimulating headphones, called Halo Sport, last month. The arch of the headphones contains two electrodes that deliver a very small amount of electric current to the wearer's head, aimed at the neurons in the motor cortex, a brain region that coördinates movement.

Perhaps the home of the future will be filled with robots. Or maybe that home itself will be a robot. That's the vision some technologists have for the future of domestic living, and a startup called Brain of Things announced Thursday that it is developing what the company's founder refers to as "robot homes" in three locations in California. These apartments come with a stunning array of sensors and automated fixtures and appliances. They also have the ability to learn and adapt to residents' habits and preferences to an almost creepy degree, thanks to computer servers that collect data and use it to build models of behavior using machine-learning algorithms.

Inside a modest-looking office building in Tokyo lives an unusually clever industrial robot made by the Japanese company Fanuc. Give the robot a task, like picking widgets out of one box and putting them into another container, and it will spend the night figuring out how to do it. Come morning, the machine should have mastered the job as well as if it had been programmed by an expert. Industrial robots are capable of extreme precision and speed, but they normally need to be programmed very carefully in order to do something like grasp an object. This is difficult and time-consuming, and it means that such robots can usually work only in tightly controlled environments.