As the previous parts of this book have shown, the engines of posttraumatic reactions are located in the emotional brain. In contrast with the rational brain, which expresses itself in thoughts, the emotional brain manifests itself in physical reactions: gut-wrenching sensations, heart pounding, breathing becoming fast and shallow, feelings of heartbreak, speaking with an uptight and reedy voice, and the characteristic body movements that signify collapse, rigidity, rage, or defensiveness.