After a sudden fright, it’s common for your heart rate to stay elevated, your palms to stay sweaty and senses to remain alert for another threat. Mice also exhibit this response and a team of Caltech researchers wanted to learn what’s happening at a cellular level in the mouse’s brain during these persistent displays of fear behavior. The team, working in the Caltech lab of David Anderson, Seymour Benzer Professor of Biology, HHMI Investigator and Director and Leadership Chair of the Tianqiao and Chrissy Chen Institute for Neuroscience, discovered that the neural mechanisms responsible are, surprisingly, located in a center of the brain that was thought to be much more evolutionarily primitive and reflexive. Their results were published in a new paper appearing in the journal Nature on September 16.