Anterior cingulate cortex volume reduction in patients with panic disorder

In chapter 12 of our textbook, panic disorder is mentioned as a clinical focus. The book reports that a small percentage of the population experiences the effects of this disorder and the major symptom is fear, including raised heart rate. The current article researches the structural brain differences in people with panic disorder. Their attention is focused on the anterior cingulate cortes, or ACC. The ACC is divided into the dorstal cognitive division and the rostral-ventral affective division, which regulates emotional responses and is linked to the amygdala. The researchers note that past "findings suggest functional abnormalities in the ACC, especially rostral-ventral affective subdivision, is certainly related with panic disorder and its symptoms." Their purpose was to delineate the "structural changes" that occur in a person with panic disorder. They mapped out ROIs (or regions of interest) and also measured VBM (voxel-based morphometry), which is basically the volume of specific regions of the brain. Researchers recruited 26 subjects with panic disorder and matched healthy participants to serve as their control group. All had been diagnosed with panic disorder by the DSM-IV Axis I disorders. They used several surveys and scales: the Panic Disorder Severity Scale, with higher scores reflecting severe symptoms, the Global Assessment of Functioning,  the State-Trait Anxiety Inventory, and the Self-Rating Depression Scale. MRI scans assessed the ROIs and mapped them out to compare the regions. The ACC has four sub-regions: Dorsal ACC, rostral ACC, subcalloal ACC, and subgenual ACC. All regions were traced by researchers who were unaware of the patients' disorder.
An independent samples t-test was performed to compare differences across regions. The VBM was performed to map our gray/white matter and cerebrospinal fluid. As I stated earlier, it was used to calculate the volume in certain regions of the brain. An ANCOVA was performed to compare the regions. A correlation analysis of ROIs was performed and no significant correlation was found. The analysis discovered there was a significant volume decrease in the right dorsal ACC, as compared to their control subjects. The researchers reported, "To our knowledge this is the first report of a sub-region specific ACC volume deficit in patients iwth panic disorder." This discovery confirms that the ACC is related to cognitive and emotional tasks and has strong ties with the amygdala, which produces the fear response. This research contributes to the knowlege base of panic disorder by concluding there are "functional as well as structural abnormalities of the ACC" in people with the disorder.

Takeshi, A., Hayano, F., Nakamura, M., Yamasue, H., Uehara, K., Otsuka, T.,...Hirayasu, Y. (2008). Anterior cingulate cortex volume reduction in patients with panic disorder. Psychiatry and Clinical Neurosciences, 62, 322-330. Retrieved from EbscoHost. doi: 10.1111/j.1440-1819.2008.01800.x

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