How does the brain respond to danger?

In the face of danger, two brain circuits become active. One circuit feeds sensory information about the danger -- the sight and smell of a fire, for example -- to the cerebral cortex (the rippled outer layer of gray matter jacketing both brain hemispheres), the thinking part of the brain. The cerebral cortex evaluates this information and makes a rational judgment about it. For example, that judgment may determine that the fire is small, but tell you to get out of the house anyway and call the fire department.

The other circuit relays the sensory information to the amygdala, which sends impulses to the autonomic nervous system. This system triggers the "fight-or-flight" response even before the cerebral cortex has made sense of the information. Once activated, it increases heart rate, routes blood to muscles, releases stress hormones and glucose into the bloodstream, and spurs other responses to help you respond quickly to the danger.

Continue Learning about Functions of the Brain

The Mediterranean Diet and Your Brain
The Mediterranean Diet and Your Brain
The word Mediterranean is Latin for “middle of the Earth.” The Ancient Romans gave the sea this name because it was the center of the earth as they kn...
Read More
What is the relationship between the stomach and the brain?
Univ. of Nev. School of Medicine, Family MedicineUniv. of Nev. School of Medicine, Family Medicine
The brain controls our entire body via the many neurons throughout our body. The stomach is related ...
More Answers
What is the function of the cerebellum in the brain?
Natalia S. Rost, MDNatalia S. Rost, MD
At the back of the brain, near the brainstem, lies the cerebellum, which is responsible for maintain...
More Answers
What Happens If I Don't Move Around During the Day?
What Happens If I Don't Move Around During the Day?

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.