The brains of people with generalized anxiety disorder (GAD) have weaker connections between a brain region in charge of emotional response and the amygdala.
This suggests that the brain’s “panic button” may be chronically pushed down due to lack of regulation, according to a new University of Wisconsin-Madison imaging study.
GAD, which is characterized by excessive, uncontrollable worry, affects nearly 6 percent of the population.
The findings support the hypothesis that reduced communications between parts of the brain result in the extreme anxiety felt by people with GAD, said lead author Jack Nitschke, Ph.D., associate professor of psychiatry.
For the study, two types of scans showed that the amygdala, which triggers the “fight-or-flight” response, appears to have weaker “white matter” connections to the prefrontal and anterior cingulate cortex, the center of emotional regulation.
Two types of imaging were used — diffusion tensor imaging (DTI) and functional magnetic resonance (fMRI) — on the brains of 49 GAD patients and 39 healthy volunteers.
Compared with the healthy participants, the scans revealed that the brains of GAD individuals had reduced connections between the prefrontal and anterior cingulate cortex and the amygdala.
These connections went through the uncinate fasciculus — a “white matter” path that connects these brain regions. This lowered connectivity was not found in other white matter tracts in other parts of the brain.
“We know that in the brain, if you use a circuit you build it up, the way you build muscle by exercise,” said Nitschke.
The question arises whether this weak connection results in the extreme defensive anxiety and worry that is the hallmark of GAD, because the anterior cingulate cortex is unable to tell the amygdala to “chill out.”
It also suggests that behavioral therapy, in which patients learn to consciously attempt to regulate this emotion, helps reduce anxiety by strengthening the connection.
“It’s possible that this is exactly what we’re doing when we teach patients to regulate their reactions to the negative events that come up in everyone’s lives,” Nitschke says.
“We can help build people’s tolerance to uncontrollable future events by teaching them to regulate their emotions to the uncertainty that surrounds those events.”
The research is published in the Archives of General Psychiatry.
Source: University of Wisconsin-Madison