Watching the brain under stress
According to this news release from the University of Pennsylvania School of Medicine, researchers have for the first time "visualized the effects of everyday psychological stress in a healthy human brain." They used the fMRI (functional magnetic resonance imaging) technique and found that there is a strong link between psychological stress and negative emotions. This research effort may help physicians to better diagnose and treat the effects of chronic stress.
Here is how the researchers did their study.
In the Penn study, researchers induced stress on healthy subjects by asking them to quickly tackle challenging mental exercises while being monitored for performance. During the fMRI scans, the researchers also recorded subjects' emotional responses -- such as stress, anxiety, and frustration -- and measured the corresponding changes in stress hormone and heart rate. Many subjects described themselves as being "flustered, distracted, rushed and upset" by the stress task.
The background of the image below "shows the mean cerebral blood flow of all the subjects undergoing the stress tasks (here, mental arithmetic) acquired using the continuous arterial spin labeling (CASL) technique. The foreground shows the detected activation in the right prefrontal cortex -- an area long associated with anxiety and depression -- when the subjects are under stress." (Credit: University of Pennsylvania School of Medicine).
And here is a link to a larger version of this image.
And here are two miniature images reflecting the brain's activity when the subject tells a lie (left) or the truth (right) (Credit: University of Pennsylvania School of Medicine). Here is a link to a poster from which this image was extracted.
Before going further, you also should watch one of the videos available from the Virtual fMRI page. The subjects need to spend about one hour in the MRI coil, without moving, and subjected to various stimuli. This should be largely enough to increase my level of stress...
But let's come back to the results of this study, which were driven by John A. Detre [,Associate Professor of Neurology and Radiology] and by Jiongjiong Wang [, Assistant Professor of Radiology.]
The results showed increased cerebral blood-flow during the "stress test" in the right anterior portion of the brain (prefrontal cortex) -- an area long associated with anxiety and depression. More interestingly, the increased cerebral blood-flow persisted even when the testing was complete.
These results suggest a strong link between psychological stress and negative emotions. On the other hand, the prefrontal cortex is also associated with the ability to perform executive functions -- such as working memory and goal-oriented behavior -- that permit humans to adapt to environmental challenges and threats.
Will this study be useful for us who are all submitted to stress? Wang thinks so.
"The message from this study is that while stress may be useful in increasing focus, chronic stress could also be detrimental to mental health."
For more information, including online publications not available today, you should visit the site of the Center for Functional Neuroimaging at the University of Pennsylvania.
Sources: University of Pennsylvania School of Medicine news release, November 21, 2005; and various web sites
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