Psychological Stress in the Healthy Human Brain

For the first time ever scientists have visualized the effects of everyday psychological stress in the healthy human brain.

Researchers at the University of Pennsylvania School of Medicine used fMRI - functional magnetic resonance imaging - to image brain activity in their subjects. The researchers induced stress on healthy subjects by asking them to quickly perform challenging mental tasks while being monitored for performance.

During the tasks, the subjects' emotional responses - such as stress, anxiety, and frustration, were measured - as well as changes in stress hormones and heart rate. Many subjects described themselves as being "flustered, distracted, rushed and upset" during the task.

During the "stress test," results showed increased blood-flow to the right prefrontal cortex of the brain - an area long associated with anxiety and depression. The increased blood-flow continued even after the task was complete. These results suggest a strong link between psychological stress and negative emotions.

Or, since the prefrontal cortex is also associated with the ability to perform executive functions, such as working memory and goal oriented behavior, this result could be highlighting that action.

"How the brain reacts under psychological stress is an untouched subject for cognitive neuroscientists, but it is certainly a critical piece of the puzzle in understanding the health effects of stress," said study leader Jiongjiong Wang. "Our findings should help significantly advance our understanding of this process."

This research is detailed in the Nov. 21 online edition of the Proceedings of the National Academy of Sciences.

--Bjorn Carey

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Credit: University of Pennsylvania School of Medicine