Does the Brain Really Have an "On-Off Switch" for Fear?

Printed in the Agoraphobia Newsletter on October 3, 2006

If it does, researchers may be closer to finding it.

A tiny, almond-shaped part of the brain called the “amygdala” houses the body’s “fight or flight” response. A recent study at Columbia Medical Center (in the U.S.) suggests that another part of the brain may control the activation of the “fight or flight” response in the amygdala, acting as an “on-off” switch for the body’s fear response.

The region of the brain that may act as the “on-off” switch for the fear response is called the rostral cingulate. If this “switch” could be manipulated, it would mean a major breakthrough in the treatment of anxiety disorders.
To observe the functioning of the rostral cingulate, researchers at Columbia University gave subjects an attention test while watching their brains on a real-time brain scan.

Subjects took the Stroop test, which is a test of mental flexibility in which people choose between a word’s definition and color. For example, a test-taker might read a list of words such as ”red,” “blue,” or “green” in which the word “red” might be written in blue ink, “blue” in purple ink and so on. People usually respond faster when the color and word match.

The Columbia team adapted the Stroop test to use emotions rather than colors. They used pictures of fearful or happy faces with the words “fear” or “happy” printed on the pictures. The researchers gave this test to 19 subjects while scanning their brain activity.

As the subjects took the test, the rostral cingulate seemed to control the fear response in the amygdala when it was activated.

For example, if the word “fear” was printed on a happy face, the amygdala activated first. Then when the image of the smiling, happy face registered, the rostral cingulate activated and the amygdala calmed down.
If the fearful face was paired with the printed word “fear,” the amygdala stayed activated longer and it took longer for the rostral cingulate to activate and produce the calming effect.

Understanding the functioning of the rostral cingulate in relation to the amygdala could help in the development of treatment for anxiety disorders like agoraphobia. For example, it could be determined if the overactive fear response could be traced back to the amygdala or the rostral cingulate control mechanism. Treatment for agoraphobia, then, could be based on a person’s specific problem.

Article Source: http://www.agoraphobia.net

Stephen Price is a recovered agoraphobic. His informational Web site on agoraphobia is found at: www.agoraphobia.ws

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