Perhaps one of the most interesting developments in the study of anxiety involves a 2013 study done at the University of Iowa.
A 40-some-year-old female patient, known to have a rare condition called Urbach-Wiethe disease, gave rise to some new ideas about the brain and panic. Her condition involved damage to the amygdala, the area in the brain known for its role in feeling fear. This meant that she was unable to feel terror/fear the way most people do.
Nonetheless, a test in which she was asked to inhale a panic-inducing dose of carbon dioxide had her crying for help as it gave her the sensation that she was suffocating.
John Wemmie, associate professor of psychiatry at the UI, was said to have felt the findings of their research indicates that panic is induced outside of the amygdala. He further mentioned the implications for understanding panic attacks.
To read more, see the Science Daily link to an article called, “Human Brain is Divided on Fear and Panic: Different Areas of Brain Responsible for External, Internal Threats.”