17 December 2010
A woman who cannot feel afraid because of a missing structure in her
brain may help scientists discover treatments for post-traumatic
stress disorder (PTSD).
Research published in Current Biology showed the woman felt no fear
when exposed to a variety of scary situations.
These included exposure to snakes and spiders, horror films and a
The woman feels other emotions but said as an adult, she had never
She is the first known case of someone who is unable to process fear.
Researchers at Iowa University said her inability to feel frightened
was because she is missing a structure in her brain called the
The structure has long been associated with emotional learning -
experiments in animals have shown that removing it makes them
However, it has never been observed in a human before.
The woman experienced fear as a child and knows that some situations
should be frightening.
As an adult she has been in various frightening situations, including
being threatened with a knife and held at gunpoint.
These did not make her afraid.
Researchers at Iowa University observed and recorded the woman's
responses in situations that would make most people feel fear.
She watched a series of horror films, went to a reputedly haunted
house and to an exotic pet store - where she handled dangerous snakes
and asked to handle a tarantula.
She showed no fear in any of the situations and had to be prevented
from from touching the tarantula because of the high risk of being
When asked why she wanted to touch something that she knows is
dangerous, she replied that she was overcome with curiosity.
Lead researcher Justin Feinstein said: "Because she is missing her
amygdala, she is also missing the ability to detect and avoid danger
in the world.
"It is quite remarkable that she is still alive."
The researchers hope that by studying the woman they can understand
how the brain processes fear.
This could be useful in treating patients suffering from PTSD - such
as soldiers who have been serving in conflict areas.
Mr Feinstein added: "Their lives are marred by fear and they are
oftentimes unable to even leave their home due to the ever-present
feeling of danger."
By studying the woman, researchers hope to create treatments that
selectively target the brain areas that can sometimes allow fear to
Truth resides in every human heart, and one has to search for it there, and to be guided by truth as one sees it. But no one has a right to coerce others to act according to his own view of truth. - Mohandas Gandhi
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