Part of the brain that causes fear identified by scientists

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Anna Brech
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 Ivy League researchers say they’ve identified where fear resides in the brain, in a finding that carries significance for the treatment of anxiety disorders.

The team of scientists from Dartmouth College found that the striatum – a part of the brain involved in motor function and decision making – enlarges in tandem with an intolerance to uncertainty, or fear of the unknown.

Justin Kim and his colleagues studied  56 mentally healthy students who underwent MRI scans of their brains. The volunteers also completed a survey that assessed their ability to cope with the uncertainty of challenges or negative events in the future.

Comparing the surveys and the brain images, the researchers identified a clear link between the size of the striatum and an aversion to ambiguity about future events. 

The findings are a starting point for scientists to potentially track the volume of the striatum, and therefore predict a young person’s risk of developing an anxiety disorder later in life.

It also opens the way for professionals to treat the symptoms of anxiety conditions, and monitor the efficacy of treatments, by observing the striatum.

“Uncertainty and ambiguity of potential future threats are central to understanding the generation of anxiety and anxiety disorders,” Kim says, in a news release from the American Psychological Association.

“People who had difficulty tolerating an uncertain future had a relatively enlarged striatum,” he adds. “What surprised us was that it was only the striatum and not other parts of the brain we examined.”

He said their results indicate a way of predicting whether someone is predisposed to anxiety or OCD, based on their intolerance to uncertainty.

“Our findings demonstrate that the relationship between increased striatal volumes and intolerance of uncertainty can be observed in healthy individuals,” Kim says.

“Having a relatively enlarged volume of the striatum may be associated with how intolerant you are when facing an uncertain future, but it does not mean you have OCD or generalized anxiety disorder.”

If you suffer from an anxiety disorder, seek help and support with Mind.

Photos: iStock


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Anna Brech

Anna Brech is a freelance journalist and former editor for Her six-year stint on the site saw her develop a vociferous appetite for live Analytics, feminist opinion and good-quality gin in roughly equal measure. She enjoys writing across all areas of women’s lifestyle content but has a soft spot for books and escapist travel content.