Abstract
BackgroundIn recent years, neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have played a significant role in elucidating the neural underpinnings of posttraumatic stress disorder (PTSD). However, a detailed understanding of the neural regions implicated in the disorder remains incomplete because of considerable variability in findings across studies. The aim of this meta-analysis was to identify consistent patterns of neural activity across neuroimaging study designs in PTSD to improve understanding of the neurocircuitry of PTSD.MethodsWe conducted a literature search for PET and fMRI studies of PTSD that were published before February 2011. The article search resulted in 79 functional neuroimaging PTSD studies. Data from 26 PTSD peer-reviewed neuroimaging articles reporting results from 342 adult patients and 342 adult controls were included. Peak activation coordinates from selected articles were used to generate activation likelihood estimate maps separately for symptom provocation and cognitive-emotional studies of PTSD. A separate meta-analysis examined the coupling between ventromedial prefrontal cortex and amygdala activity in patients.ResultsResults demonstrated that the regions most consistently hyperactivated in PTSD patients included mid- and dorsal anterior cingulate cortex, and when ROI studies were included, bilateral amygdala. By contrast, widespread hypoactivity was observed in PTSD including the ventromedial prefrontal cortex and the inferior frontal gyrus. Furthermore, decreased ventromedial prefrontal cortex activity was associated with increased amygdala activity.ConclusionsThese results provide evidence for a neurocircuitry model of PTSD that emphasizes alteration in neural networks important for salience detection and emotion regulation.
Highlights
In recent years, neuroimaging techniques such as functional magnetic resonance imaging and positron emission tomography (PET) have played a significant role in elucidating the neural underpinnings of posttraumatic stress disorder (PTSD)
The analysis showed that when the ventromedial prefrontal cortex was hypoactivated, greater amygdala activation was observed in PTSD, supporting the hypothesis that activity in the ventromedial prefrontal cortex and amygdala are inversely related
Dorsomedial prefrontal regions have been associated with appraisal and evaluation whereas ventromedial prefrontal regions are associated with regulatory functions. This dissociation is consistent with the findings reported here, where more dorsal prefrontal regions, including the dorsomedial prefrontal cortex and mid/dorsal anterior cingulate cortex were active in patients with PTSD and may suggest heightened appraisals of potential threats in the environment, whereas hypoactivity in ventromedial prefrontal regions may reflect dysfunction in emotion regulation
Summary
In recent years, neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have played a significant role in elucidating the neural underpinnings of posttraumatic stress disorder (PTSD). A detailed understanding of the neural regions implicated in the disorder remains incomplete because of considerable variability in findings across studies. The aim of this metaanalysis was to identify consistent patterns of neural activity across neuroimaging study designs in PTSD to improve understanding of the neurocircuitry of PTSD. In the aftermath of highly distressing and shocking events such as combat, genocide, and rape, a subset of individuals develop posttraumatic stress disorder (PTSD), which is characterized by distressing memories of the event, physiological hyperarousal, and impairment in daily functioning. Exposure therapy, which involves the principles of extinction learning [30], is one of the most effective therapeutic interventions for PTSD
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