New study contends different areas of brain responsible for
external versus internal threats
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.