Human Brain Is Divided On Fear and Panic: Different Areas of Brain Responsible for External, Internal Threats
Feb. 4, 2013 — When doctors at the University of Iowa prepared a patient to inhale a panic-inducing dose of carbon dioxide, she was fearless. But within seconds of breathing in the mixture, she cried for help, overwhelmed by the sensation that she was suffocating.
The patient, a woman in her 40s known as SM, has an extremely rare condition called Urbach-Wiethe disease that has caused extensive damage to the amygdala, an almond-shaped area in the brain long known for its role in fear. She had not felt terror since getting the disease when she was an adolescent.
In a paper published online Feb. 3 in the journal Nature Neuroscience, the UI team provides proof that the amygdala is not the only gatekeeper of fear in the human mind. Other regions — such as the brainstem, diencephalon, or insular cortex — could sense the body’s most primal inner signals of danger when basic survival is threatened.
“This research says panic, or intense fear, is induced somewhere outside of the amygdala,” says John Wemmie, associate professor of psychiatry at the UI and senior author on the paper. “This could be a fundamental part of explaining why people have panic attacks.“
nterestingly, the amygdala-damaged patients had no fear leading up to the test, unlike the healthy participants, many who began sweating and whose heart rates rose just before inhaling the carbon dioxide. That, of course, was consistent with the notion that the amygdala detects danger in the external environment and physiologically prepares the organism to confront the threat.
“Information from the outside world gets filtered through the amygdala in order to generate fear,” Feinstein says. “On the other hand, signs of danger arising from inside the body can provoke a very primal form of fear, even in the absence of a functioning amygdala.”
- New Study Contends Different Areas Of Brain Responsible For External Versus Internal Threats (medicalnewstoday.com)
- Humans Can Feel Terror Even If They Lack Brain’s ‘Fear Center’ (scientificamerican.com)
- Human brain is divided on fear and panic (sciencedaily.com)