Amygdala volume in adults with posttraumatic stress disorder: a meta-analysis.
ABSTRACT Posttraumatic stress disorder (PTSD) may be associated with structural abnormalities in the amygdala. To better characterize amygdala volume in PTSD, the authors conducted a meta-analysis comparing amygdala volumes in PTSD patients and comparison subjects. Using electronic databases, the authors found nine studies comparing amygdala volumes in adult subjects with PTSD with amygdala volumes in comparison subjects (participants unexposed to trauma and participants exposed to trauma but without PTSD). Results showed no significant differences in amygdala volumes between the groups. Within each group, the right amygdala was significantly larger than the left, indicating an asymmetrically lateralized amygdala volume that is preserved in trauma exposure and in PTSD.
- SourceAvailable from: Taylor Keding[Show abstract] [Hide abstract]
ABSTRACT: Structural brain studies of adult PTSD show reduced gray matter volume (GMV) in fear regulatory areas including the ventromedial prefrontal cortex (vmPFC) and hippocampus. Surprisingly, neither finding has been reported in pediatric PTSD. One possibility is that they represent age-dependent effects that are not fully apparent until adulthood. Additionally, lower resolution MRI and image processing in prior studies may have limited detection of such differences. Here we examine fear circuitry GMV, including age-related differences, using higher resolution MRI in pediatric PTSD vs. healthy youth. In a cross-sectional design, 3T anatomical brain MRI was acquired in 27 medication-free youth with PTSD and 27 healthy non-traumatized youth of comparable age, sex, and IQ. Voxel-based morphometry was used to compare GMV in a priori regions including the medial prefrontal cortex and amygdala/hippocampus. Compared to healthy youth, PTSD youth had reduced GMV but no age-related differences in anterior vmPFC (BA 10/11, Z=4.5), which inversely correlated with PTSD duration. In contrast, while there was no overall group difference in hippocampal volume, a group X age interaction (Z=3.6) was present in the right anterior hippocampus. Here, age positively predicted hippocampal volume in healthy youth but negatively predicted volume in PTSD youth. Within the PTSD group, re-experiencing symptoms inversely correlated with subgenual cingulate (sgACC, Z=3.7) and right anterior hippocampus (Z=3.5) GMV. Pediatric PTSD is associated with abnormal structure of the vmPFC and age-related differences in the hippocampus, regions important in the extinction and contextual gating of fear. Reduced anterior vmPFC volume may confer impaired recovery from illness, consistent with its role in the allocation of attentional resources. In contrast, individual differences in sgACC volume were associated with re-experiencing symptoms, consistent with the role of the sgACC in fear extinction. The negative relationship between age and hippocampal volume in youth with PTSD may suggest an ongoing neurotoxic process over development, which further contributes to illness expression. Future studies employing a longitudinal design would be merited to further explore these possibilities.Neuropsychopharmacology accepted article preview online, 12 September 2014. doi:10.1038/npp.2014.239.Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 09/2014; 40(3). DOI:10.1038/npp.2014.239 · 7.83 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: We previously reported that hippocampal volume was associated with current, but not lifetime posttraumatic stress disorder (PTSD) symptom severity. In the present study, we test the hypothesis that like the hippocampus, the volumes of other brain regions previously implicated in PTSD, are also negatively related to current, but not lifetime PTSD symptom severity. One hundred ninety-one veterans underwent structural magnetic resonance imaging (MRI) on a 4T scanner. Seventy-five veterans were trauma unexposed, 43 were trauma exposed without PTSD, 39 were trauma exposed with current PTSD, and 34 were trauma exposed veterans with remitted PTSD. Hippocampal, amygdala, rostral and caudal anterior cingulate, insula, and corpus callosum volumes, quantified with Freesurfer version 4.5, were analyzed by group using multivariate analysis of covariance. Veterans with PTSD had smaller hippocampal, caudal anterior cingulate, insula, and corpus callosum volumes than the unexposed controls (p≤0.009); smaller hippocampal, caudal anterior cingulate, insula (p≤0.009) and marginally smaller corpus callosum (p=0.06) than veterans with remitted PTSD; and smaller hippocampal and caudal anterior cingulate volumes than veterans without PTSD (p≤0.04). In contrast, there was no significant volume differences between veterans with remitted PTSD compared to those without PTSD or unexposed controls. The finding that current but not lifetime PTSD accounts for the volumes of multiple brain regions suggests that either smaller brain volume is a vulnerability factor that impedes recovery from PTSD or that recovery from PTSD is accompanied by a wide-spread restoration of brain tissue.06/2013; 213(3). DOI:10.1016/j.pscychresns.2013.03.002
- [Show abstract] [Hide abstract]
ABSTRACT: There is a high degree of intra-individual variation in how individuals respond to stress. This becomes evident when exploring the development of posttraumatic symptoms or stress-related disorders after exposure to trauma. Whether or not an individual develops posttraumatic symptoms after experiencing a traumatic event is partly dependent on a person's resilience. Resilience can be broadly defined as the dynamic process encompassing positive adaptation within the context of significant adversity. Even though research into the neurobiological basis of resilience is still in its early stages, these insights can have important implications for the prevention and treatment of stress-related disorders. Neuroimaging studies contribute to our knowledge of intra-individual variability in resilience and the development of posttraumatic symptoms or other stress-related disorders. This review provides an overview of neuroimaging findings related to resilience. Structural, resting-state, and task-related neuroimaging results associated with resilience are discussed. There are a limited number of studies available and neuroimaging research of resilience is still in its infancy. The available studies point at brain circuitries involved in stress and emotion regulation, with more efficient processing and regulation associated with resilience.Frontiers in Behavioral Neuroscience 05/2013; 7:39. DOI:10.3389/fnbeh.2013.00039 · 4.16 Impact Factor