Brain Scans Find Spot That Links Stress to Asthma

I've been out sick from work for two days...asthmatic bronchitis.
I also am stressed at work...is this a correlation?

Using brain scanning techniques, researchers have located a specific part of the brain that causes people with asthma to wheeze and gasp for breath when under emotional stress.

Their report, released on Aug. 29, will appear in the Sept. 13 issue of The Proceedings of the National Academy of Sciences.

Asthma sufferers often note that anxiety and emotional turmoil make the symptoms of an attack much worse, and in some cases, emotion alone can precipitate an attack.

Previous research has shown, for example, that college students with asthma have greater airway inflammation when they are exposed to an allergen during exam week than when the exposure occurs at a less stressful time.

Though these psychological exacerbations of asthma were well known, the physical connection between the brain and the immune system had not been described.

Richard J. Davidson, the senior author of the paper and a professor of psychology and psychiatry at the University of Wisconsin, said the work showed that when people with asthma are exposed to their allergen, "you find certain centers in the brain that we know are intimately involved in emotions that get activated."

In asthma attacks there are at least two phases. First, the inhalation of an allergen provokes a release of chemicals that cause smooth muscles to contract. A result is the tightness in the chest that many asthma sufferers feel when an attack begins. Then, other cells are activated that release chemicals called cytokines to fight off the invading allergen. This causes inflammation.

Together, these reactions bring on airway obstruction and difficulty in breathing.

In the new study, the researchers exposed six volunteers with mild allergic asthma to two different substances, one that caused muscle constriction, and a second that caused inflammation.

At one hour and four hours after the exposure, the participants' brains were scanned using functional M.R.I., essentially photographing the brain's activity during the muscle constriction stage and then at the inflammation stage of the attack.

During the scans, the participants were asked to read words shown on a screen. Some were emotionally neutral, like "curtains." Others, like "lonesome," were likely to provoke negative emotions. Still other words were specifically associated with asthma attacks, like "wheeze," "cough" or "suffocate."

The researchers found that brain activity in the early muscle contracting phase of the asthma attack differed from that in the later inflammatory phase.

They also found that the presentation of words specifically associated with asthma attacks caused increased activity in the inflammatory phase in parts of the brain that govern emotions. This effect was not apparent when the subjects were shown the neutral or negative words.

The authors said the study had certain limitations. It involved a small number of subjects, and, therefore, only the strongest brain activity was likely to be detected statistically. And, they said, it is likely that parts of the brain other than those examined in this study are involved in the process.

Still, they said, the data may have broader implications for the role of the central nervous system in causing or controlling inflammation, and the study reveals an unknown link between the brain and physiological events in a separate part of the body.