MRI-Based Measurement of Hippocampal Volume in Patients with Combat-Related Posttraumatic Stress Disorder
ABSTRACT Studies in nonhuman primates suggest that high levels of cortisol associated with stress have neurotoxic effects on the hippocampus, a brain structure involved in memory. The authors previously showed that patients with combat-related posttraumatic stress disorder (PTSD) had deficits in short-term memory. The purpose of this study was to compare the hippocampal volume of patients with PTSD to that of subjects without psychiatric disorder.
Magnetic resonance imaging was used to measure the volume of the hippocampus in 26 Vietnam combat veterans with PTSD and 22 comparison subjects selected to be similar to the patients in age, sex, race, years of education, socioeconomic status, body size, and years of alcohol abuse.
The PTSD patients had a statistically significant 8% smaller right hippocampal volume relative to that of the comparison subjects, but there was no difference in the volume of other brain regions (caudate and temporal lobe). Deficits in short-term verbal memory as measured with the Wechsler Memory Scale were associated with smaller right hippocampal volume in the PTSD patients only.
These findings are consistent with a smaller right hippocampal volume in PTSD that is associated with functional deficits in verbal memory.
Full-textDOI: · Available from: John Seibyl, Jul 29, 2015
- SourceAvailable from: Gilbert Wallace Kliman
- "The central nervous system arousal is emphatically limbic, especially of the hippocampus and particularly of certain nuclei such as the locus ceruleus. Imaging studies show that when the disorder is chronic, these over-aroused areas become atrophied—particularly the right hippocampus (Bremner, 1995) and, in addition, there is some less significant frontal lobe atrophy. The negative PTSD phenomena I consider associated with the brain atrophy, especially in the right hippocampus, are reduced short term memory and reduced memory for early periods of childhood. "
Research: Toward a Unifying Theory of PTSD[Show description] [Hide description]
DESCRIPTION: An effort to integrate data from videotaped interviews of severely traumatized persons (especially children) with physiological, imaging, and psychological studies in light of evolutionary theory of altruism.
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- "Studies investigating the neural correlates of PTSD are also of particular interest for the present article. Beginning with Bremner et al.'s (1995) study of Vietnam combat veterans suffering from PTSD, an elevated number of neuroimaging studies (Bremner et al., 1997, 2003; Lindauer et al., 2004; Stein, Koverola, Hanna, Torchia, & McClarty, 1997; Villarreal et al., 2002; Wignall et al., 2004) have demonstrated that PTSD patients show a significant reduction in the volume of their hippocampus relative to control subjects. Specifically, in a recent metaanalysis of 13 studies using magnetic resonance imaging, Smith (2005) estimated that PTSD individuals had a 6.6% smaller right hippocampal volume and a 6.9% smaller left hippocampal volume in comparison with well-matched control participants , encompassing both trauma-exposed individuals who did not develop PTSD and subjects without significant trauma exposure. "
ABSTRACT: The authors review five arguments supporting the hypothesis that memories for traumatic and nontraumatic emotional events should be considered as qualitatively different recollections. The first argument considers the objective features of traumatic and emotional events and their possible influence on the formation of memories for these events. The second argument assumes that traumatic memories distinguish from emotional ones as trauma exposure is often associated with the development of psychological disorders involving memory disturbances. The third argument is that traumatic experiences are more likely than emotional experiences to be forgotten and recovered. The fourth argument concerns the possibility that emotional memories are socially shared more frequently than traumatic memories. A fifth argument suggests that trauma exposure may impair selected brain systems implicated in memory functions. Theoretical and empirical evidence supporting these claims is reviewed. In the conclusions, the authors illustrate future research directions and discuss some conceptual issues related to the definitions of traumatic event currently employed by memory researchers.The Journal of Psychology Interdisciplinary and Applied 09/2014; 148(5):523-47. DOI:10.1080/00223980.2013.814619 · 0.86 Impact Factor
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- "This parallels human functional imaging data that show greater amygdala activation in human populations with PTSD (Liberzon et al., 1999; Shin, Rauch, & Pitman, 2006). Moreover, it has been observed that there is a reduction in hippocampal volume in PTSD patients (Bremner et al., 1995; Woon, Sood, & Hedges, 2010), but despite this, many functional imaging studies have reported greater hippocampal activation in this patient population (Osuch et al., 2001; Sachinvala, Kling, Suffin, Lake, & Cohen, 2000; Shin et al., 2006; Thomaes et al., 2009; Werner et al., 2009). These outcomes observed in humans with PTSD parallel what many have observed following chronic stress considering dendritic atrophy in the hippocampus as an indirect measure of volume (Hoffman et al., 2011; Tata & Anderson, 2010; Watanabe, Gould, & McEwen, 1992 "
ABSTRACT: Chronic stress may impose a vulnerability to develop maladaptive fear-related behaviors after a traumatic event. Whereas previous work found that chronic stress impairs the acquisition and recall of extinguished fear, it is unknown how chronic stress impacts nonassociative fear, such as in the absence of the conditioned stimulus (CS) or in a novel context. Male rats were subjected to chronic stress (STR; wire mesh restraint 6h/d/21d) or undisturbed (CON), then tested on fear acquisition (3 tone-footshock pairings), and two extinction sessions (15 tones/session) within the same context. Then each group was tested (6 tones) in the same context (SAME) or a novel context (NOVEL), and brains were processed for functional activation using Fos immunohistochemistry. Compared to CON, STR showed facilitated fear acquisition, resistance to CS extinction on the first extinction day, and robust recovery of fear responses on the second extinction day. STR also showed robust freezing to the context alone during the first extinction day compared to CON. When tested in the same or a novel context, STR exhibited higher freezing to context than did CON, suggesting that STR-induced fear was independent of context. In support of this, STR showed increased Fos-like expression in the basolateral amygdala and CA1 region of the hippocampus in both the SAME and NOVEL contexts. Increased Fos-like expression was also observed in the central amygdala in STR-NOVEL vs. CON-NOVEL. These data demonstrate that chronic stress enhances fear learning and impairs extinction, and affects nonassociative processes as demonstrated by enhanced fear in a novel context.Neurobiology of Learning and Memory 07/2014; 112. DOI:10.1016/j.nlm.2014.01.018 · 4.04 Impact Factor