Neuroscientists have set their sights on identifying the network of cells, circuits, and chemicals—the brain's "jury room," so to speak—where the evidence is weighed and verdicts decided. "There are extremely few examples where we really know what the nervous system is doing from sensory input to a behavior," says Cornelia Bargmann, an HHMI investigator at Rockefeller University. "We can map them out in simple reflexes, like an animal's escape response, but what we'd really like to understand is the steps by which information is transformed and integrated all the way through."

Illustration: Barry Falls