US scientists activate predatory 'kill switch' in mice

US scientists have ramped up predatory behavior in mice by stimulating a region of the brain known for its role in emotions like fear and pleasure, according to a study published Thursday. The experiment turned the lab mice into super-eating machines, vigorously attacking food, bottle caps, and sticks as prey, said the findings in the journal Cell. "A major issue for neuroscientists is how the brain figures out how to respond appropriately to objects in the world," lead author Ivan de Araujo, associate professor of psychiatry at the Yale University School of Medicine, told AFP.