A baby born too soon continues to develop and grow inside an incubator at the neonatal ward of the Centre Hospitalier de Lens in Lens, northern France. Philippe Huguen/AFP/Getty Images hide caption

itoggle caption Philippe Huguen/AFP/Getty Images

A technique called optogenetics is being used in the laboratory to observe and control what brain circuits are doing in real time. Henning Dalhoff/Getty Images/Science Photo Library RM hide caption

itoggle caption Henning Dalhoff/Getty Images/Science Photo Library RM

Bartender Matt Carucci says he rarely feels safe biking in the city but often rides without a helmet anyway. "There are a lot of other ways to hurt yourself," he says. John Rose/NPR hide caption

itoggle caption John Rose/NPR

The most common cause of brain injury in premature infants is a lack of oxygen in the days and weeks after birth, researchers say. Ibrahim Usta/AP hide caption

itoggle caption Ibrahim Usta/AP