An American woman, whose identity remains secret, suffers from a rare disease that affects the part of her brain responsible for feeling the emotion of fear.
Because of her condition, the 50-or-so-year-old woman has no sense of self-preservation and pets dangerous animals gladly. In her life she has faced several dangerous situations, which did not even make her blink.
The part of the brain affected is the amygdala. The woman can feel anger, grief or joy but to researchers' shock, she is not familiar with fear.
The American woman makes it clear that she does remember this feeling from her childhood but years later, when the disease most likely developed, she no longer felt fear.
Researchers from the University of Iowa have studied the woman's reactions and found that in different situations, in which most people would feel afraid, she did not display such emotions.
The results of their study may be of aid to people who suffer from heavy posttraumatic stress or anxiety disorders.
The researchers claimed that during testing, she showed perfect results when they studied her memory, speech, intelligence and perceptions.
The woman was taken to a pet store, where she was fascinated by the dangerous snakes and even wanted to pet the tarantula but was stopped due to the risk of being bitten by the poisonous spider.
She can watch scary movie scenes without blinking, the scientists told Current Biology journal.
With 3 children, the American woman bearing the initials C.M. has had a lot more than 1 or 2 stressful moments in her life. She has been threatened with a firearm and knife during an assault, and she was the victim of domestic violence in her family.
But this did not have any effect on her behavior at all, studies claim.
"Whenever the amygdala does not function, C.M. does not recognize the danger, nor can she avoid it. It's a real miracle that she's still alive, " clarify scientists.
Such personality disorders are well-known in psychology and are explained by a traumatic childhood memory.