MADISON -- The mere mention of a stressful word like "wheeze" canactivate two brain regions in asthmatics during an attack, and thisbrain activity may be associated with more severe asthma symptoms,according to a study by University of Wisconsin-Madison researchers andcollaborators.
The study, which appears in the Proceedings of the National Academyof Sciences (Online, August 29, 2005), reveals a functional linkbetween emotion processing centers in the brain and certainphysiological processes relevant to disease.
UW-Madison psychology professor Richard Davidson, an expert onemotions; and UW-Madison medicine professor William Busse, an expert onasthma; are senior co-authors on the study. Melissa Rosenkranz, agraduate student at the UW-Madison Laboratory for AffectiveNeuroscience, is the lead author.
"While this study was small, it shows how important specificbrain circuits can be in modulating inflammation," says Davidson,director of the affective neuroscience laboratory and the WaismanLaboratory for Functional Brain Imaging and Behavior. "The data suggestpotential future targets for the development of drugs and behavioralinterventions to control asthma and other stress-responsive disorders."
Previous studies and clinical evidence have shown that stressand emotional turmoil adversely affect people with inflammatorydiseases like asthma. And signs of inflammation have been shown toaffect the brain. But until now, nobody knew exactly what braincircuits were involved in these seemingly intertwined emotional andimmune events or how the circuits might influence the severity of anacute asthma response.
Researchers used functional magnetic resonance imaging (fMRI)to scan the brains of six mildly asthmatic people who were asked toinhale ragweed or dust-mite extracts.
Subjects were then shown three types of words: asthma-related(such as "wheeze"), non-asthma negative (such as "loneliness") andneutral (such as "curtains"). Shortly after, researchers measured lungfunction in the subjects as well as molecular signs of inflammation intheir sputum.
The fMRI scans revealed that the asthma-related termsstimulated robust responses in two brain regions--the anteriorcingulate cortex and the insula--that were strongly correlated withmeasures of lung function and inflammation. The other types of wordswere not strongly associated with lung function or inflammation.
The two brain structures are involved in transmittinginformation about the physiological condition of the body, such asshortness of breath and pain levels, says Davidson, and they havestrong connections with other brain structures essential in processingemotional information.
"In asthmatics, the anterior cingulate cortex and the insulamay be hyper-responsive to emotional and physiological signals, likeinflammation, which may in turn influence the severity of symptoms,"says Davidson.
The researchers suspect that other brain regions may also be involved in the asthma-stress interaction.
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