Scientists have pinpointed a part of the brain which they say causes people to experience fear — a finding that could lead to new effective treatment for post-traumatic stress disorder (PTSD) and other anxiety conditions.
Researchers at the University of Iowa have found an almond-shaped brain region, called the amygdala, that develops the emotion of fear.
Past studies have already shown that amygdala plays a central role in generating fear reactions in animals from rats to monkeys.
But the new study confirms for the first time that the amygdala is also required for triggering a state of fear in humans.
The researchers, who detailed their findings in the journal Current Biology, based the study on a woman identified only as SM, who has a rare condition that destroyed her amygdala.
The team observed the patient’s response to frightening stimuli such as a haunted house, snakes, spiders, and horror films, and asked her about traumatic experiences in her past — including situations that had endangered her life.
They found that without a functioning amygdala, the patient is unable to experience fear. Previous studies with this patient confirmed she cannot recognise fear in facial expressions, but it was unknown until this study if she had the ability to experience fear herself.
Senior study author Daniel Tranel, a professor of neurology and psychology at UI, said the discovery could lead to new interventions for PTSD and related anxiety disorders.
PTSD affects more than 7.7 million people in the US alone and a 2008 analysis by the Rand Corporation predicted that 300,000 soldiers returning from combat in West Asia would experience PTSD.
“This finding points us to a specific brain area that might underlie PTSD,” said Dr Tranel, director of the UI’s interdisciplinary graduate programme in Neuroscience. —PTI