14 DAY TRIAL // Scientists at the Stanford University Medical Center recently announced that they might have discovered a new explanation for why one of the most common types of anxiety disorders appeared. They argue that the condition may be caused by scrambled neural connections between regions of the cortex dealing with integrating fear and emotion. The study is extremely important, because it gives scientists a new way of finding the biological differences that exist between the various types of anxiety, as well as in the case of depression.
Details of the new work were published in the December 7 issue of the respected scientific journal Archives of General Psychiatry. The researchers focused all their attention on a group of patients suffering from the generalized anxiety disorder, or GAD. This condition makes these people live in a constant state of worrying, even over the most ordinary matters. It has been known for a long time that the brain region known as the amygdala, which controls emotion, memory and fear, plays an important role in diseases such as GAD. But, now, scientists were for the first time able to observe neural pathways going to and out of the tiny, almond-shaped structure.
“If we want to distinguish GAD from other anxiety disorders, we might have to look at these subregions instead of the general signal from this area. It's methodologically really impressive,” Kevin LaBar, PhD, who is a neuroscientist based at the Duke University, says. The brains of all the study participants, including some people who were psychologically sane, were analyzed using an imaging technique known as functional Magnetic Resonance Imaging. What fMRI actually does is create a map of the brain regions that benefit from increased blood flows, as the brain processes specific types of information.
“The basolateral amygdala was less connected with all of its targets and more connected with centromedial targets. And the centromedial was less connected with its normal targets and more connected with the basolateral targets,” Stanford psychiatry resident Amit Etkin, MD, PhD, reveals. He says that the connections between the various areas of the amygdala were maintained, but that they were “muddled” in the GAD patients. “This is a nice example of neurology and psychiatry joining forces,” Stanford Assistant Professor of Neurology and Neurological Sciences Michael Greicius, MD, who is also the senior author of the new journal entry, concludes.