Exploring the Neurocircuitry Underpinning Predictability of Threat in Soldiers with PTSD Compared to Deployment Exposed Controls.

Q4 Medicine
Open Neuroimaging Journal Pub Date : 2016-10-31 eCollection Date: 2016-01-01 DOI:10.2174/1874440001610010111
Michael N Dretsch, Kimberly H Wood, Thomas A Daniel, Jeffrey S Katz, Gopikrishna Deshpande, Adam M Goodman, Muriah D Wheelock, Kayli B Wood, Thomas S Denney, Stephanie Traynham, David C Knight
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引用次数: 0

Abstract

Background: Prior work examining emotional dysregulation observed in posttraumatic stress disorder (PTSD) has primarily been limited to fear-learning processes specific to anticipation, habituation, and extinction of threat. In contrast, the response to threat itself has not been systematically evaluated.

Objective: To explore potential disruption in fear conditioning neurocircuitry in service members with PTSD, specifically in response to predictable versus unpredictable threats.

Method: In the current study, active-duty U.S. Army soldiers with (PTSD group; n = 38) and without PTSD (deployment-exposed controls; DEC; n = 40), participated in a fear-conditioning study in which threat predictability was manipulated by presenting an aversive unconditioned stimulus (UCS) that was either preceded by a conditioned stimulus (i.e., predictable) or UCS alone (i.e., unpredictable). Threat expectation, skin conductance response (SCR), and functional magnetic resonance imaging (fMRI) signal to predictable and unpredictable threats (i.e., UCS) were assessed.

Results: Both groups showed greater threat expectancy and diminished threat-elicited SCRs to predictable compared to unpredictable threat. Significant group differences were observed within the amygdala, hippocampus, insula, and superior and middle temporal gyri. Contrary to our predictions, the PTSD group showed a diminished threat-related response within each of these brain regions during predictable compared to unpredictable threat, whereas the DEC group showed increased activation.

Conclusion: Although, the PTSD group showed greater threat-related diminution, hypersensitivity to unpredictable threat cannot be ruled out. Furthermore, pre-trauma, trait-like factors may have contributed to group differences in activation of the neurocircuitry underpinning fear conditioning.

探索创伤后应激障碍士兵与部署暴露对照组相比威胁可预测性的神经回路基础。
背景:之前研究创伤后应激障碍(PTSD)中观察到的情绪失调的工作主要局限于对威胁的预期、习惯化和消退等特定的恐惧学习过程。相比之下,对威胁本身的反应还没有进行过系统的评估:目的:探讨创伤后应激障碍服役人员的恐惧调节神经回路可能受到的干扰,特别是对可预测威胁和不可预测威胁的反应:在本研究中,患有创伤后应激障碍的现役美国陆军士兵(创伤后应激障碍组;n = 38)和未患有创伤后应激障碍的现役美国陆军士兵(部署暴露对照组;DEC;n = 40)参加了一项恐惧条件反射研究,在该研究中,威胁可预测性是通过呈现一种厌恶性非条件刺激(UCS)来操纵的。对可预测和不可预测威胁(即 UCS)的威胁预期、皮肤传导反应(SCR)和功能磁共振成像(fMRI)信号进行了评估:结果:与不可预测的威胁相比,两组受试者均表现出更大的威胁预期,且对可预测威胁的威胁诱发的 SCR 均有所减弱。在杏仁核、海马、脑岛、颞上回和颞中回观察到显著的组间差异。与我们的预测相反,与不可预测的威胁相比,创伤后应激障碍组在这些脑区中的威胁相关反应都有所减弱,而 DEC 组的激活反应则有所增强:结论:虽然创伤后应激障碍组显示出更大的威胁相关减弱,但不能排除对不可预测威胁的超敏反应。此外,创伤前的特质类因素也可能导致了恐惧条件反射神经回路激活的组间差异。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Open Neuroimaging Journal
Open Neuroimaging Journal Medicine-Radiology, Nuclear Medicine and Imaging
CiteScore
0.70
自引率
0.00%
发文量
3
期刊介绍: The Open Neuroimaging Journal is an Open Access online journal, which publishes research articles, reviews/mini-reviews, and letters in all important areas of brain function, structure and organization including neuroimaging, neuroradiology, analysis methods, functional MRI acquisition and physics, brain mapping, macroscopic level of brain organization, computational modeling and analysis, structure-function and brain-behavior relationships, anatomy and physiology, psychiatric diseases and disorders of the nervous system, use of imaging to the understanding of brain pathology and brain abnormalities, cognition and aging, social neuroscience, sensorimotor processing, communication and learning.
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