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Functional MRI Shows Stress Affects Brain’s Memory Processing
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With the help of functional MRI (fMRI), Italian researchers at the University of Udine have found that in patients who suffer from stress-related psychiatric disorders, the neural circuitry that links the prefrontal cortex to the hippocampus is dysfunctional, hampering memory suppression.
With the help of functional MRI (fMRI), Italian researchers at the University of Udine have found that in patients who suffer from stress-related psychiatric disorders, the neural circuitry that links the prefrontal cortex to the hippocampus is dysfunctional, hampering memory suppression.
"For patients with major depression and other stress-related disorders, traumatic memories are a source of anxiety," said Nivedita Agarwal, MD, radiology resident, University of Udine, and research fellow, Brain Imaging Center of McLean Hospital, Department of Psychiatry, Harvard Medical School, Boston. "Because traumatic memories are not adequately suppressed by the brain, they continue to interfere with the patient's life."
Exploring these neural circuitries, Agarwal and colleagues asked participants—11 with major depression, 13 with generalized anxiety disorder, nine with panic attack disorders, five with borderline personality disorder, and 21 who were healthy, all whom reported varying degrees of stressful traumatic events during their lives—to perform a memory task; participants reviewed a list of neutral word pairs, and then underwent fMRI, during which they were presented with one of the words and asked to recall or suppress an associated memory.
Compared with healthy patients, in those with stress-related disorders, fMRI images revealed that the prefrontal cortex showed abnormal activation, affecting suppression and retrieval of memories processed by 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," said Agarwal "These patients often complain of poor memory, which might in part be attributed to this altered circuitry.”
Agarwal added that “fMRI is an important tool in understanding the neurobiological basis of psychiatric disorders and in identifying imaging markers to psychiatric disease, helping clinicians target specific parts of the brain for treatment.”
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