Browsing by Subject "Mental Recall"
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Item A DRM Study of Trauma Memory Among Employees of New York City Companies Affected by the September 11, 2001 Attacks(2015-03-24) Triantafyllou, Dinara; North, Carol S.BACKGROUND: PTSD has been found to be associated with abnormalities in memory function. This relationship has not previously been studied with the Deese-Roediger-McDermott (DRM) false memory paradigm in disaster-exposed populations. OBJECTIVE: This study aims to describe the relationship between exposure to trauma, PTSD, and changes in memory. METHODS: Three years after the September 11 (9/11) attacks, 281 participants from a volunteer sample of 379, recruited from eight companies affected by the attacks, completed an interview about their disaster experience, a structured diagnostic interview, and the DRM paradigm. RESULTS: It was hypothesized that participants with PTSD would demonstrate more associative errors, termed false alarms to critical lures, compared to those without PTSD. This hypothesis was not supported; the only predictor of false alarms to critical lures was direct 9/11 trauma exposure. CONCLUSION: The finding that 9/11 trauma exposure was associated with false alarms to critical lures suggests that neural processing of trauma exposure memory may involve associative elements of overgeneralization coupled with insufficient inhibition of responses to related but harmless stimuli. Future research will be needed to differentiate psychopathology, such as PTSD, from physiological fight-or-flight responses to trauma.Item Exploring the Role and Sensitivity of the Hippocampal Dentate Gyrus: From Addiction-Relevant Memories to the Influence of Space Radiation on Hippocampal Neurogenesis(2015-04-09) Rivera, Phillip Daniel; German, Dwight; Eisch, Amelia J.; Chen, Benjamin P.; Powell, Craig M.; Zhang, Chun-LiThe hippocampus and its subregion the dentate gyrus (DG) are involved in learning and memory. Adult hippocampal neurogenesis, which takes place in the DG, is also thought to contribute to learning and memory. Understanding the neural basis of learning and memory could help in a wide range of situations, from helping addicts break the cycle of substance abuse to ensuring appropriate astronaut action during spaceflight missions. This doctoral dissertation spans this wide range by using animal models relevant to addiction and spaceflight to improve understanding of the DG and adult neurogenesis, and obliquely, of learning and memory. After an introductory chapter, I show morphine-context reward memories are established via drug/context associations (D/CA, Chapter 2), and require adult neurogenesis for extinction of young reward memories (Chapter 3). Using conditioned place preference, a behavioral test classically used to assess drug strength, and the immediate early gene cFos as an indirect marker of neuronal activity, I found that morphine-paired mice sequestered to a morphine-paired context had more DG cFos+ cells than those sequestered to a saline-paired context or other controls. Thus, the retrieval of D/CA memory is accompanied by activation of hippocampal DG neurons. Surprisingly, image-guided cranial irradiation (IG-IR) prevented extinction of young, but not old, morphine D/CA memories without affecting retrieval. These data suggest that deficits in adult neurogenesis may contribute to stronger D/CA reward memory. The second section of my dissertation (Chapter 4) examines the influence of space radiation on adult neurogenesis. I find acute and fractionated space radiation similarly diminish adult neurogenesis, but neither decrease neural stem cell number, the putative source of new neurons. Thus, while spaceflight mission success may be hampered by space radiation due to diminished neurogenesis, my data raise the possibility that neurogenesis may recover overtime. Taken together, my data show an impaired DG (and perhaps neurogenesis) diminishes extinction of morphine-context reward memories, and that adult neurogenesis is decreased (perhaps reversibly) by space radiation. In my final chapter (Chapter 5), I discuss implications of these data for the fields of learning/memory and neuroscience in general, and suggest future directions that may help addicts recover and allow astronauts to perform optimally during spaceflight missions.Item A Study of Trauma Memory in Survivors of the 9/11 Attacks Using the Deese-Roediger-McDermott (DRM) Memory Paradigm(2013-01-22) Yangirova, Dinara; North, Carol S.; Zarkin, Andrea; Roediger, Henry L., IIIBACKGROUND. PTSD has been found to be associated with abnormalities in memory function. This relationship has not previously been studied with the Deese-Roediger-McDermott (DRM) paradigm in disaster-exposed populations. The DRM paradigm uses semantically related and unrelated intrusions in an immediate test of recited word lists. It was hypothesized that PTSD would be associated with false alarms to critical lures in the DRM paradigm. METHODS. Approximately three years after the 9/11 attacks, a volunteer sample (N=379) was recruited from members of eight participating agencies (three agencies in the WTC towers and one nearby agency, three agencies that provided 9/11 disaster recovery services, and an airline that lost personnel and property in the attacks). This sample was assessed for individual disaster experience and related psychiatric status using a fully structured diagnostic interview to assess full DSM-IV-TR criteria. At the end of the interview, the DRM paradigm was administered to test participants' recognition of words. RESULTS. No associations were found between PTSD or other psychopathology and DRM memory variables. The only predictor of false alarms to critical lures was direct exposure to 9/11 trauma, which was not associated with correct identification of recited words or with false alarms to unrelated lures. DISCUSSION. The study's hypothesis that PTSD would be associated with false alarms to critical lures was not supported. The finding that direct 9/11 endangerment was associated with critical lures was unexpected. The results suggest that neural processing of trauma exposure may involve associative processes of overgeneralization in cognitive processing coupled with insufficient inhibition of responses to associated but harmless stimuli. The findings of this study also support the importance of differentiating psychopathology such as PTSD from normal physiologic fight-or-flight responses to trauma in studies of memory and neurobiological investigations of trauma and its effects in future research.