Researchers using functional MRI (fMRI) have determined that the circuitry in the area of the brain responsible for suppressing memory is dysfunctional in patients suffering from stress-related psychiatric disorders.
“For patients with major depression and other stress-related disorders, traumatic memories are a source of anxiety,” said Nivedita Agarwal, M.D., radiology resident at the University of Udine in Italy. “Because traumatic memories are not adequately suppressed by the brain, they continue to interfere with the patient’s life.”
Dr. Agarwal and colleagues used brain fMRI to explore alterations in the neural circuitry that links the prefrontal cortex to the hippocampus, while study participants performed a memory task. All patients reported s varying degrees of stressful traumatic events, such as sexual or physical abuse, difficult relationships or bullying or harassment – in their lives.
The fMRI images revealed that the prefrontal cortex, which controls the suppression and retrieval of memories processed by the hippocampus, showed abnormal activation in the patients with stress-related disorders compared to the healthy controls. During the memory suppression phase of the test, patients with stress-related disorders showed greater activation in the hippocampus, suggesting that insufficient activation of the prefrontal cortex could be the basis for inadequate suppression of unwanted traumatic memories stored in the hippocampus.
“These data suggest that the mechanism for memory suppression is dysfunctional in patients with stress-related disorders primarily because of an alteration of the prefrontal cortex,” Dr. Agarwal said. “These patients often complain of poor memory, which might in part be attributed to this altered circuitry,” she added.
Adapted from materials provided by Radiological Society of North America