Corticolimbic Blood Flow During Nontraumatic Emotional Processing in Posttraumatic Stress Disorder
University of Chicago, Chicago, Illinois, United States Archives of General Psychiatry
(Impact Factor: 14.48).
03/2006; 63(2):184-92. DOI: 10.1001/archpsyc.63.2.184
Recent brain imaging studies implicate dysfunction of limbic and paralimbic circuitry, including the amygdala and medial prefrontal cortex (MPFC), in the pathogenesis of posttraumatic stress disorder (PTSD) during traumatic recollection and imagery. However, the relationship between activity in these regions and general emotional processing unrelated to traumatic experience has not been fully examined.
To investigate activity in the limbic and paralimbic brain regions in PTSD in response to a challenge with emotionally salient generic visual images.
Cross-sectional, case-control study.
Academic medical center.
Sixteen Vietnam veterans with combat-related PTSD (PTSD group), 15 combat-exposed Vietnam veterans without PTSD (combat control group), and 15 age- and sex-matched healthy controls (normal control group).
We used positron emission tomography to study regional cerebral blood flow while participants viewed complex visual pictures with negatively valenced/aversive, nonaversive ("neutral"), and blank pictures. Psychophysiologic and emotional self-report data were also recorded.
All 3 groups activated the dorsal MPFC to general salient content. Controls without PTSD activated the left amygdala in response to aversive stimuli. Normal controls activated the ventral MPFC and combat-exposed non-PTSD and PTSD participants exhibited either no response or deactivation in these regions, respectively, during negative emotional experience.
Consistent with current functional neuroanatomic models, patients with PTSD exhibited altered neural responses in the amygdala and ventral MPFC during the processing of emotionally salient but trauma-unrelated stimuli, potentially reflecting disorder-specific changes. Activation of the amygdala and lack of ventral MPFC deactivation to negatively valenced images in combat controls may reflect compensatory changes after trauma exposure that are not associated with PTSD.
Available from: Barbara Ganzel
- "Researches of fMRI in nonclinical trauma-exposed individuals reported aberrant neural function in frontolimbic regions (Ganzel et al., 2007; New et al., 2009; Phan et al., 2006). A longitudinal fMRI study of the effects of combat exposure on military paramedics found increased activation in the amygdala, hippocampus, and ventromedial PFC in response to masked trauma-related stimuli (Admon et al., 2009). "
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ABSTRACT: The great Sichuan earthquake in China on May 12th, 2008 was a traumatic event to many who live near the earthquake area. However, at present, there are few studies that explore the long-term impact of the adolescent trauma exposure on adult's brain function. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the brain activation evoked by masked trauma-related stimuli (earthquake versus neutral images) in 14 adults who lived near the epicenter of the great Sichuan earthquake when they were adolescents (trauma-exposed group) and 14 adults who lived farther from the epicenter of the earthquake when they were adolescents (control group). Compared with the control group, the trauma-exposed group showed significant elevation of activation in the right anterior cingulate cortex (ACC) and the medial prefrontal cortex (MPFC) in response to masked earthquake-related images. In the trauma-exposed group, the right ACC activation was negatively correlated with the frequency of symptoms of post-traumatic stress disorder (PTSD). These findings differ markedly from the long-term effects of trauma exposure in adults. This suggests that trauma exposure during adolescence may have a unique long-term impact on ACC/MPFC function, top-down modulation of trauma-related information, and subsequent symptoms of PTSD.
Copyright © 2014. Published by Elsevier B.V.
Available from: Sanne J.H. Van Rooij
- "Here, we included a large group of PTSD patients and compared them with both trauma and healthy control groups, thus this cannot explain the absence of differences. Like Phan et al (2006), who also did not observe an increased amygdala response to IAPS pictures in PTSD patients, we only studied males. The two studies that presented IAPS pictures and observed increased amygdala activity in PTSD patients included predominantly females (Brohawn et al. 2010; Brunetti et al. 2010). "
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Post-traumatic stress disorder (PTSD) is thought to be characterized by general heightened amygdala activation. However, this hypothesis is mainly based on specific studies presenting fear or trauma-related stimuli, hence, a thorough investigation of trauma-unrelated emotional processing in PTSD is needed.
In this study, 31 male medication-naive veterans with PTSD, 28 male control veterans (combat controls; CC) and 25 non-military men (healthy controls; HC) were included. Participants underwent functional MRI while trauma-unrelated neutral, negative and positive emotional pictures were presented. In addition to the group analyses, PTSD patients with and without major depressive disorder (MDD) were compared.
All groups showed an increased amygdala response to negative and positive contrasts, but amygdala activation did not differ between groups. However, a heightened dorsal anterior cingulate cortex (dACC) response for negative contrasts was observed in PTSD patients compared to HC. The medial superior frontal gyrus was deactivated in the negative contrast in HC, but not in veterans. PTSD+MDD patients showed decreased subgenual ACC (sgACC) activation to all pictures compared to PTSD-MDD.
Our findings do not support the hypothesis that increased amygdala activation in PTSD generalizes to trauma-unrelated emotional processing. Instead, the increased dACC response found in PTSD patients implicates an attentional bias that extends to trauma-unrelated negative stimuli. Only HC showed decreased medial superior frontal gyrus activation. Finally, decreased sgACC activation was related to MDD status within the PTSD group.
Available from: Christine A Rabinak
- "For instance, increased reactivity to emotional stimuli in PTSD may be primarily observed for traumaspecific stimuli (e.g., personalized scripted imagery of trauma), whereas decreased or normative reactivity may be more frequently observed for generic threat depictions (e.g., threatening faces;Casada, Amdur, Larsen, & Liberzon, 1998;Pineles, Shipherd, Mostoufi, Abramovitz, & Yovel, 2009). Combat-related PTSD, in particular, has been associated with reduced response when processing non-traumatic threatening/aversive stimuli (Armony, Corbo, Clément, & Brunet, 2005;Phan et al., 2006). Additionally, the type of 'control' stimuli that are used may impact results: for example, among studies that use facial stimuli to evaluate threat-processing in PTSD, neutral faces may not provide the most appropriate comparison, because anxious individuals may interpret even these baseline stimuli differently than non-anxious individuals (Cooney, Atlas, Joormann, Eugène, & Gotlib, 2006;Somerville, Kim, Johnstone, Alexander, & Whalen, 2004). "
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ABSTRACT: Post-traumatic stress disorder (PTSD) is characterized by avoidance, emotional numbing, increased arousal and hypervigilance for threat following a trauma. Thirty-three veterans (19 with PTSD, 14 without PTSD) who had experienced combat trauma while on deployment in Iraq and/or Afghanistan completed an emotional faces matching task while electroencephalography was recorded. Vertex positive potentials (VPPs) elicited by happy, angry and fearful faces were smaller in veterans with versus without PTSD. In addition, veterans with PTSD exhibited smaller late positive potentials (LPPs) to angry faces and greater intrusive symptoms predicted smaller LPPs to fearful faces in the PTSD group. Veterans with PTSD were also less accurate at identifying angry faces, and accuracy decreased in the PTSD group as hyperarousal symptoms increased. These findings show reduced early processing of emotional faces, irrespective of valence, and blunted prolonged processing of social signals of threat in conjunction with impaired perception for angry faces in PTSD.
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