Researchers at Johns Hopkins think they have identified sites in the brain where "worrying" takes place. Using brain scans that measure blood flow variations, the scientists concluded that several structures on the right side are the site of anxious thoughts.
For the study, presented at the annual meeting of the Society for Neuroscience, 10 volunteers made short tapes describing their worries: recent family crises, stress in theworkplace, financial problems, or other troubles. After volunteers listened to the same tapes, their brains were immediately scanned with a technique called functional positron emission tomography (PET), which detects differences in blood flow, an indicator of brain activity.
Subjects also were scanned after listening to "neutral" tapes about flower auctions and flower arrangements.
"We subtracted the scans to find the difference, and it was clear that several areas on the right became more active during worrying," says Rudolf Hoehn-Saric, M.D., director of the anxiety disorders unit at Johns Hopkins.
"We saw an increase in the right frontal lobe, the planning and decision-making part of the brain, and in other areas on the right that are involved in arousal, self-examination and processing of new inputs," says Hoehn-Saric. The other areas included the basal ganglia, which coordinate and process messages from various parts of the brain; the cerebellum, whose functions include storing "routines"--frequently used patterns of thought or movements; and the pontine nuclei, which regulate arousal.
The new finding makes sense in light of historic evidence that the left side of the brain is involved in analytical thinking and the right in emotional, according to Hoehn-Saric.
"Worrying occurs when no easy solution is available, and the solution is often derived emotionally rather than rationally," he notes.
Scientists plan to follow up with studies of patients with anxiety disorders, psychiatric conditions that disable them with overwhelming concern about a particular aspect of their lives, such as cleanliness or their physical surroundings. Comparisons of the two studies could help scientists find anxiety disorders' origins in the brain.
Other authors on the study were Thomas Zeffiro, Daniel McLeod, Fuji Yokoi, Sally Symanski, Godfrey Pearlson, and Dean Foster Wong. This research was funded by the National Institutes of Health.