Heart in your throat. Butterflies in your stomach. Bad gut feeling. These are all phrases many people use to describe fear and anxiety. You have likely felt anxiety inside your chest or stomach, and your brain usually doesn't hurt when you're scared. Many cultures tie cowardice and bravery more to the heart or the guts than to the brain. I am a psychiatrist and neuroscientist who researches and treats fear and anxiety. In my book 'Afraid,' I explain how fear works in the brain and the body and what too much anxiety does to the body. Research confirms that while emotions do originate in your brain, it's your body that carries out the orders. While your brain evolved to save you from a falling rock or speeding predator, the anxieties of modern life are often a lot more abstract. Fifty-thousand years ago, being rejected by your tribe could mean death, but not doing a great job on a public speech at school or at work doesn't have the same consequences. Your brain, however, might not know the difference....