Animal studies have shown that early stressors result in lasting changes in structure
and function of brain areas involved in memory, including hippocampus and frontal
cortex. Patients with childhood abuse-related posttraumatic stress disorder (PTSD)
have alterations in both declarative and nondeclarative memory function, and imaging
studies in PTSD have demonstrated changes in function during stimulation of trauma-specific
memories in hippocampus, medial prefrontal cortex, and cingulate. The purpose of this
study was to assess neural correlates of emotionally valenced declarative memory in
women with early childhood sexual abuse and PTSD.
Women with early childhood sexual abuse-related PTSD (n = 10) and women without abuse
or PTSD (n = 11) underwent positron emission tomographic (PET) measurement of cerebral
blood flow during a control condition and during retrieval of neutral (e.g., "metal-iron")
and emotionally valenced (e.g., "rape-mutilate") word pairs.
During retrieval of emotionally valenced word pairs, PTSD patients showed greater
decreases in blood flow in an extensive area, which included orbitofrontal cortex,
anterior cingulate, and medial prefrontal cortex (Brodmann's areas 25, 32, 9), left
hippocampus, and fusiform gyrus/inferior temporal gyrus, with increased activation
in posterior cingulate, left inferior parietal cortex, left middle frontal gyrus,
and visual association and motor cortex. There were no differences in patterns of
brain activation during retrieval of neutral word pairs between patients and control
subjects.
These findings are consistent with dysfunction of specific brain areas involved in
memory and emotion in PTSD. Regions implicated in this study of emotionally valenced
declarative memory are similar to those from prior imaging studies in PTSD using trauma-specific
stimuli for symptom provocation, adding further supportive evidence for a dysfunctional
network of brain areas involved in memory, including hippocampus, medial prefrontal
cortex, and cingulate, in PTSD.