Scientists Seek a Better Understanding of Fear
> 10/31/2007 12:28:30 PM

As Halloween night approaches, children and their parents prepare to walk the darkened streets as vampires, witches, and zombies. For some, however, situations that others view as commonplace, walking at night, for example, can lead to overwhelming fear. Fear affects us all, but for some people, relentless fears never seem to go away or appear to have no cause. By studying how fear develops in the brain and how it affects our thoughts and behavior, researchers hope to help those who suffer from anxiety, panic attacks, and phobias to overcome their greatest fears.

According to the National Institute of Mental Health, 40 million Americans suffer from anxiety disorders, and scientists continue to search for more information about why fear dominates the lives of so many people. In a study due to appear in the November 2007 issue of the journal Emotion, researchers at Vanderbilt University discovered that fear may be one of our strongest and most easily-recognized emotions. Participants in the study used a viewer, which is similar to a microscope's eyepiece, to look at pictures of people displaying fearful, happy, or neutral expressions. Utilizing a technique known as continuous flash suppression, where one eye views a static image and the other eye views a pattern flashed repeatedly, the researchers reduced the time necessary for the brain to recognize facial information. Information that can normally be processed in 40 milliseconds now took as long as 10 seconds. The subjects reported when they could see a face, and the results show that they became aware of fearful faces more quickly than they became aware of happy or neutral faces. The researchers point to the amygdala, a small region of the brain involved in memory and emotional responses, as the reason for this quick reaction to fear. They believe the amygdala may process some visual signals and reacts quickly when presented with indications of fear, like the whites of the eyes are visible. By picking up on fearful expressions and reacting instantly, our brains help us avoid potential dangers in the environment.

Researchers have long known that the amygdala plays a role in how we react to scary situations, and they have turned to this area of the brain when looking for ways to help people overcome their fears. Last year, researchers led by Michael Davis of Emory University studied the effectiveness of D-cycloserine, an antibiotic commonly prescribed for tuberculosis, in treating people suffering from phobias. They found that D-cycloserine binds to the NMDA receptor and increases its activity in the amygdala, and this reaction reduces the time needed to overcome a phobia. After successfully testing the theory in rats, they gave people with a fear of heights either a dose of D-cycloserine or a placebo before a therapy session. During therapy, the subjects were asked to wear a virtual reality headset that duplicated the experience of riding a glass elevator to the top of all tall building and then walking out onto beam hanging high in the air. During the session, both groups reported feeling the same amount of fear. The situation was repeated a week later, and those who took D-cycloserine reported feeling less afraid than those who took the placebo. In two weeks those who took D-cycloserine were able to make the same amount of progress that would normally be seen after eight weeks of therapy. With further research, D-cycloserine in combination with therapy could become an effective form of treatment, and the researchers plan to continue studying the effects of D-cycloserine on other types of phobias and anxiety disorders.

Though we cannot conquer fear completely, we can try to understand why fear is a necessary emotion and why, at times, it can get out of hand. When fear does overtake us, we can help ease its grasp by questioning whether or not our fear stems from an actual threat or merely an imagined one. By realizing that a fear is not a reaction to actual danger, we can reduce anxiety and begin to calm down. When fear becomes overwhelming and unrelenting, however, the normal routine of life cannot continue, so it is important that researchers continue to study fear and discover new ways of combatting it.

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