Michael Davis Few scientists have charted the grim territory of fear and anxiety with the same doggedness and precision as Michael Davis. Nearly four decades ago, researchers learned that animals, including humans, startle more when fearful. A sudden noise in a dark, creepy alley provokes a greater reaction than in a well-lit room, for instance. That got Davis and his colleagues wondering what neural mechanisms underlie the startle reflex, and how fear plays a part in the response. In his talk, Davis describes the meticulous experiments he and others have conducted over many years. Starting with the fear potentiated startle test -- where animals are trained to pair a stimulus such as light, or sound, with a shock -- researchers began to track the pathways that mediate the response in the nervous system. Using chemical tracers that could follow electrical activity in the brain, Davis found a group of cells in the central nucleus of the amygdala that are critical for fear...