Morey Rajendra A, Dolcos Florin, Petty Christopher M, Cooper Debra A, Hayes Jasmeet Pannu, LaBar Kevin S, McCarthy Gregory
Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA.
J Psychiatr Res. 2009 May;43(8):809-17. doi: 10.1016/j.jpsychires.2008.10.014. Epub 2008 Dec 16.
The relevance of emotional stimuli to threat and survival confers a privileged role in their processing. In PTSD, the ability of trauma-related information to divert attention is especially pronounced. Information unrelated to the trauma may also be highly distracting when it shares perceptual features with trauma material. Our goal was to study how trauma-related environmental cues modulate working memory networks in PTSD. We examined neural activity in participants performing a visual working memory task while distracted by task-irrelevant trauma and non-trauma material. Recent post-9/11 veterans were divided into a PTSD group (n=22) and a trauma-exposed control group (n=20) based on the Davidson trauma scale. Using fMRI, we measured hemodynamic change in response to emotional (trauma-related) and neutral distraction presented during the active maintenance period of a delayed-response working memory task. The goal was to examine differences in functional networks associated with working memory (dorsolateral prefrontal cortex and lateral parietal cortex) and emotion processing (amygdala, ventrolateral prefrontal cortex, and fusiform gyrus). The PTSD group showed markedly different neural activity compared to the trauma-exposed control group in response to task-irrelevant visual distractors. Enhanced activity in ventral emotion processing regions was associated with trauma distractors in the PTSD group, whereas activity in brain regions associated with working memory and attention regions was disrupted by distractor stimuli independent of trauma content. Neural evidence for the impact of distraction on working memory is consistent with PTSD symptoms of hypervigilance and general distractibility during goal-directed cognitive processing.
情绪刺激与威胁及生存的相关性使其在加工过程中具有特殊作用。在创伤后应激障碍（PTSD）中，与创伤相关的信息转移注意力的能力尤为显著。当与创伤材料具有相同感知特征时，与创伤无关的信息也可能极具干扰性。我们的目标是研究与创伤相关的环境线索如何调节PTSD中的工作记忆网络。我们检测了参与者在执行视觉工作记忆任务时的神经活动，此时他们会受到与任务无关的创伤和非创伤材料的干扰。根据戴维森创伤量表，近期参与过9·11事件后的退伍军人被分为PTSD组（n = 22）和创伤暴露对照组（n = 20）。使用功能磁共振成像（fMRI），我们测量了在延迟反应工作记忆任务的主动维持期呈现的情绪（与创伤相关）和中性干扰物所引起的血液动力学变化。目的是检查与工作记忆（背外侧前额叶皮层和外侧顶叶皮层）和情绪加工（杏仁核、腹外侧前额叶皮层和梭状回）相关的功能网络的差异。与创伤暴露对照组相比，PTSD组在对与任务无关的视觉干扰物的反应中表现出明显不同的神经活动。在PTSD组中，腹侧情绪加工区域的活动增强与创伤干扰物有关，而与工作记忆和注意力区域相关的脑区活动则受到与创伤内容无关的干扰物刺激的破坏。干扰对工作记忆影响的神经证据与PTSD在目标导向认知加工过程中的过度警觉和普遍易分心症状相一致。
