Fear is essential for survival, but must be well regulated to avoid harmful behaviors such as panic attacks or exaggerated risk taking. Scientists have now demonstrated in mice that the brain relies on the body's feedback to regulate fear. The brain's insular cortex strongly reacts to stimuli signaling danger. However, when the body freezes in response to fear, the heartbeat slows down leading to attenuated insular cortex activity. Processing these opposing signals helps the insular cortex to keep fear in balance. The body's reactions are thus actively used to regulate emotions and are much more than passive emotional responses.