Have you ever set off on a trip with a nagging sense that you have left something important behind; you think hard; nothing comes to mind. It’s as if your body knows but can’t speak. Eventually, halfway to your destination, the item pops into your head. Even if the item was important, along with the feeling of frustration, you’ll probably notice a release of tension in your body. We tend to live in our heads a lot of the time, thinking about plans, people, problems, or past memories and sometimes completely forgetting that we have a body at all. In our heads, we tend to think that all useful processing happens in our brain, yet the whole of our body is interconnected with a complex nervous system. Like many other animals, we have a central nervous system that includes the brain and spinal cord. Although we think of the brain as a separate organ, it’s really a specialized part of the whole nervous system. The spinal cord, which contains over thirteen million neurons, is connected to the limbs and organs by the peripheral nervous system, which extends across the whole of the body.