If anxiety is in my brain, why is my heart pounding? A psychiatrist explains the neuroscience and physiology of fear
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 heartor the guts than to the brain.
But science has traditionally seen the brain as the birthplace and processing site of fear and anxiety. Then why and how do you feel these emotions in other parts of your body?
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.
Fear and the brain
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.
There are a few key areas of the brain that are heavily involved in processing fear.
When you perceive something as dangerous, whether it’s a gun pointed at you or a group of people looking unhappily at you, these sensory inputs are first relayed to the amygdala. This small, almond-shaped area of the brain located near your ears detects salience, or the emotional relevance of a situation and how to react to it. When you see something, it determines whether you should eat it, attack it, run away from it or have sex with it.
Threat detection is a vital part of this process, and it has to be fast. Early humans did not have much time to think when a lion was lunging toward them. They had to act quickly. For this reason, the amygdala evolved to bypass brain areas involved in logical thinking and can directly engage physical responses. For example, seeing an angry face on a computer screen can immediately trigger a detectable response from the amygdala without the viewer even being aware of this reaction.
The hippocampus is near and tightly connected to the amygdala. It’s involved in memorizing what is safe and what is dangerous, especially in relation to the environment – it puts fear in context. For example, seeing an angry lion in the zoo and in the Sahara both trigger a fear response in the amygdala. But the hippocampus steps in and blocks this response when you’re at the zoo because you aren’t in danger.
The prefrontal cortex, located above your eyes, is mostly involved in the cognitive and social aspects of fear processing. For example, you might be scared of a snake until you read…