【作者】 张妍；

【导师】 陈红；

【作者基本信息】 西南大学 ， 基础心理学， 2012， 博士

【摘要】 创伤后压力反应(post-traumatic stress reaction)不同于创伤后应激障碍(post-traumatic stress disorder, PTSD)。PTSD是个体在遭遇或对抗重大创伤性事件后,其心理状态失调产生的症状。而创伤后压力反应是普遍存在于创伤个体中的现象,并且强调这种现象是经历创伤所产生的合理结果,而非病患心理状态。虽然大多数个体在经历创伤性事件后都会出现程度不等的症状,但只有一部分人最终成为PTSD患者。由于汶川特大地震的影响面极大,使得相当数量的人出现了创伤后压力反应。从已有研究来看,多数研究者以PTSD患者为被试,探讨创伤性经历对其认知加工神经机制的影响,而少有从预防和发展的角度关注没有表现出PTSD症状的非临床被试。在认知神经科学领域的已有研究中,多数研究都局限于探讨表现出创伤后应激障碍的地震亲历者的脑区激活情况,而少有运用事件相关电位(event related potentials, ERP)技术从加工时程方面分析地震亲历者的认知特点。本研究在前期问卷调查的基础上,主要运用ERP实验技术,在汶川地震两年后,考察没有出现PTSD(?)临床症状的地震亲历者对威胁性信息认知加工的特点。本文共包括7个研究,19个实验,从创伤后压力反应的主要方面：注意、记忆、情绪加工,分别在两个维度上：不同灾难暴露程度(经历组和未经历组)以及不同年龄阶段(中学生和大学生)比较分析了地震亲历者创伤后压力反应的神经生理机制。(1)不同灾难暴露程度(经历组和未经历组)地震亲历者创伤后压力反应的神经生理机制第一部分(包括研究1、研究2和研究3)：地震亲历者对威胁性刺激注意偏向的ERP研究。研究1运用线索提示范式(cue-target paradigm)考察了地震亲历者对威胁性刺激注意资源的空间分配特点。行为结果以及P3潜伏期和峰值上的效应发现,不论是地震词还是中性词,中学生经历组都比未经历组更加警觉。行为和N1峰值的效应发现,大学生经历组比未经历组对地震词更加回避。但是,研究1并没有发现地震亲历者在地震词和中性词上注意偏向的差异。这可能与线索刺激与靶刺激之间的时间间隔有关。鉴于此,研究1采用阈上呈现威胁性刺激的方式考察注意的定向和维持,而研究2则运用视觉点探测掩蔽任务(masked version of the dot probe task),通过阈下呈现刺激的方式考察地震亲历者的注意从威胁性刺激到探测点位置的注意转移过程中认知加工的时程动态变化特点。通过比较一致条件和不一致条件下早期成分N1、P1和P2潜伏期与峰值的特点发现,中学生经历组比未经历组对地震词更加警觉。研究1和研究2从注意的成分理论探讨了地震亲历者对威胁性刺激的注意偏向及其神经机制,然而,我们仍不清楚是否地震亲历者对中性刺激也存在同样的认知加工特点。因此,通过研究3对此进行了探讨。研究3通过经典的oddball实验范式研究发现,在后部脑区,中性靶刺激对中学生经历组比未经历组诱发的P1和P300波幅更弱。由此可以推测,地震亲历者可能存在注意加工的缺陷。这也与临床上PTSD的症状一致。尽管PTSD患者集中注意力的能力降低了,但轻微的创伤性刺激就能够诱发闯入性记忆和闪回现象的出现。为此,研究4考察了地震亲历者是否对地震威胁性刺激存在记忆偏向。第二部分(研究4)：地震亲历者对威胁性刺激记忆偏向的ERP研究。研究4采用学习-再认(study-test)范式中新／旧测试的实验任务发现,地震图片与中性图片相比,引起了地震亲历者更长的反应时,更高的正确率,以及更大的P3和LPC峰值效应。对负性刺激认知偏向的研究可以很好地解释地震相关图片比中性图片会诱发更大的ERP效应。另外,根据Brewin提出的双向呈现理论(duel representation theory)(?)阳记忆-视觉神经认知模型(neurocognitive model of memory and imagery),与自我密切相关的创伤性经历在情景记忆加工的神经机制中可能是至关重要的,这促使被试在回忆灾难场景时在大脑产生了生动的画面,即我们通常所说的“闪光灯记忆”(flashbulb memory)或者闪回现象。此外,还有可能是创伤性记忆对地震亲历者的情绪性记忆造成了影响。有研究表明PTSD患者主诉记忆障碍并不能真正反映记忆损害,相反它提示了共病情绪障碍的危险性。根据多重记忆系统说(multiple memory systems view),脑内存在着结构和功能不同的多个记忆系统,通过启动效应使得存在于这些记忆系统中的图示被激活。那么,这些情景性记忆或者情绪性记忆以何种方式储存在记忆系统中的?又如何对认知加工产生作用?因此,研究5和研究6考察了威胁性刺激启动效应对地震亲历者情绪加工的影响。第三部分(研究5和研究6)：威胁性刺激启动效应对地震亲历者情绪加工影响的ERP研究。研究5采用阈上情绪启动(supraliminal emotional priming)的实验范式,从行为和ERP结果来看,并没有发现显著的启动效应。这可能和启动-靶刺激的时间间隔(stimulus onset asynchrony, SOA)有关,研究表明情绪启动效应大部分是在较短的SOA内出现的。为了说明个体是否受到了阈下,即无意识情绪启动的影响,研究6采用阈下情绪启动(subliminal emotional priming)的实验范式考察了威胁性刺激阈下启动效应对地震亲历者情绪加工的影响。结果发现,对于中学生组,地震图片启动下经历组对恐惧面孔的反应时更短,对高兴面孔的反应时更长,且对于中学生和大学生经历组,对恐惧面孔的反应时均比未经历组更短；同时,地震图片启动下,恐惧面孔对中学生经历组诱发的N1、P1、P2和LPC效应比未经历组更大。可见,地震图片启动下,地震亲历者对恐惧面孔的敏感性增强。那么,是否可以通过认知和神经生理的训练改变心理和行为的反应呢?研究7对此进行了探索。第四部分(研究7)：地震亲历者认知与脑功能修复中的神经可塑性研究。从研究5和研究6可见,创伤性经历对地震亲历者的情绪功能产生了影响,使其对负性情绪信息的敏感性增强。因此,研究7以生物反馈训练调节地震亲历者焦虑情绪为例,开展了应用神经可塑性原理修复脑功能的探索性研究。结果表明,生物反馈训练能够有效缓解地震亲历者的负性情绪,通过脑电指标证实了地震亲历者认知与脑功能修复中的神经可塑性。这也为从神经生理层面对地震亲历者进行干预和治疗以改善其心理和行为问题提供了物质基础和现实可能。(2)不同年龄阶段(中学生和大学生)地震亲历者创伤后压力反应的神经生理机制创伤后应激障碍的研究表明,年龄是一个非常重要的危险因素。年龄越小者,越容易出现创伤后应激症状。因此,本文对不同年龄地震亲历者的注意偏向、记忆偏向、情绪加工的神经生理机制进行了比较。在研究1和研究2中,行为结果和ERP早期成分P1效应显示,中学生经历组比大学生经历组对地震词更加警觉；在研究3中,中性靶刺激对中学生经历组比大学生经历组诱发的P300波幅更小；在研究4中,中学生经历组在旧的地震图上P3成分的潜伏期短于大学生经历组,旧的地震图对中学生组诱发的P3峰值和LPC波幅大于大学生组；在研究5和研究6中,行为结果和N1、P1成分的ERP效应表明,威胁性刺激对中学生情绪加工的阈下启动效应更大,且中学生经历组比大学生经历组的情绪敏感性更强,尤其是对负性情绪。这些结果表明地震创伤性经历对中学生经历组有更大的影响。这可能与中学生群体脑与认知的发展特点有关。基于以上研究,我们发现个体的心理和行为反应是大脑各个部分协同运作的结果,因此,构建了基于地震亲历者对威胁性刺激认知加工的创伤后压力反应合作认知模型(Post-Traumatic Stress Reaction Cooperation Cognitive Model, PTSR-CCM)。PTSR-CCM是反应地震亲历者对威胁性刺激认知加工特征的模型,包括三个模块和一个原理,即本研究考察的四个方面：注意功能、记忆功能、情绪功能、神经可塑性,试图揭示威胁性刺激对非临床被试创伤后压力反应作用的神经生理机制。更多还原

【Abstract】 Post-traumatic stress reaction is different from post-traumatic stress disorder. PTSD is a kind of psychological disorder or symptom after suffering traumatic event. However, post-traumatic stress reaction is commonly found in traumatic individuals, which is reasonable result of traumatic event, rather than a kind of psychological disorder or symptom. Although most of individuals will have different symptoms after experiencing traumatic event, only few of them eventually become PTSD patients. In term of the Wenchuan earthquake had a prevalent impact, huge amounts of people have presented post-traumatic stress reactions.In the most of previous studies, PTSD patients were selected as subjects to explore the influence of traumatic experience on their cognitive neural mechanisms. However, there were few studies to concern the non-clinical survivors who had not presented PTSD symptoms from the viewpoint of prevention and development. Besides, in the field of cognitive neuroscience research, most studies were limited to explore the activated brain regions of PTSD patients. However, there were few studies on cognitive temporal processing characteristic of earthquake-exposed survivors using event related potentials technology (ERP). Based on our previous questionnaire surveys, the current study explored the cognitive processing of the earthquake-exposed group to threat stimuli without PTSD using ERP experiment technology after two years of the Wenchuan earthquake.The dissertation totally included7studies and19experiments. We compared the neurophysiology mechanism of post-traumatic stress reaction (attention, memory and emotion processing) from two dimensions. One was the different degree of earthquake exposure (exposed group and non-exposed group), and the other was different age group (high school student and college student).(1) The neurophysiology mechanism of post-traumatic stress reaction of groups in different degree of earthquake exposure (exposed group and non-exposed group).The first part (including Study1,2and3) was a series of ERP studies on attention bias to threat in earthquake-exposed survivors. Study1investigated the space distribution features of attention resources to threat in earthquake-exposed survivors using a cue-target paradigm. The behavioral and P3latency and peak effect indicated that high school students were more vigilance for cue words in the earthquake-exposed group compared with in the non-exposed group. Meanwhile, the behavioral and Nl peak effect indicated that college students were more avoidant to threat cue words in the earthquake-exposed group compared with in the non-exposed group. However, Study1did not find the difference of attention bias between threat and neutral cue words. It may be related to the time interval of cues and targets.Therefore, Study1tested attention orienting and engagement by supraliminal threat cues, but Study2investigated attention shift by subliminal threat using masked version of the dot probe task. The earlier N1, P1and P2latencies and peaks within valid and invalid trials showed that earthquake-exposed high school students were more vigilance for threat than non-exposed high school students. Even though Study1and Study2tested the attention bias to threat within the theoretical framework of components of attention orienting, it was still unclear that whether there were same cognitive processing characteristics to neutral stimuli in earthquake-exposed survivors. So we did Study3to test it.Study3found that neutral target elicited significantly more reduced P1and P300for earthquake-exposed high school students compared with for non-exposed high school students in posterior scalp using a classic oddball paradigm. It speculated that earthquake-exposed high school students might have attention processing deficits, which was consistent with clinical PTSD symptoms. Although PTSD patients have the disability to focus, a mild traumatic stimulation can induce invasive memory and the phenomenon of flashbacks. Therefore, Study4examined the memory bias to threat in earthquake-exposed survivors.The second part (Study4) was an ERP study on memory bias to threat in earthquake-exposed survivors. Study4found that earthquake pictures elicited longer reaction time, higher accuracy and greater P3and LPC amplitudes effect compared with neutral pictures in earthquake-exposed group using an old/new recognition study-test task. The results on negative stimulation bias can explain the reason of earthquake pictures had enhanced effect compared with neutral pictures. In addition, in terms of Brewin’s "duel representation theory" and "neurocognitive model of memory and imagery", it assumed that closely related personal traumatic experiences might be important in the neural mechanisms of episodic memory processing, which produced vivid pictures when recalling disaster scene, i.e."flashbulb memory". However, there was another explain that traumatic experiences might influenced emotional memory of the earthquake-exposed group. Because some study has showed that memory disorders of PTSD patients can’t really reflect memory impairment; instead, it is the risk hint of emotional disorders. According to the "multiple memory systems view", there are many brain memory systems with different structure and function. The initial graphical representation existing in the memory system is activated by the priming effect. How did these kinds of episodic memory or emotional memory store in memory systems, and work on cognitive processing? Therefore, Study5and Study6examined the impact of threat priming effect on emotional processing in earthquake-exposed survivors.The third part (Study5and Study6) was on the impact of threat priming effect on emotional processing in earthquake-exposed survivors. Study5used the supraliminal emotional priming paradigm. The behavioral and ERP results revealed that the priming effect is not significant. It may be related to the time interval of priming and target stimuli, i.e. stimulus onset asynchrony (SOA). Because some research found that only a short SOA could lead to priming effect. In order to test the impact of subliminal priming, i.e. unconscious emotional priming, Study6used the subliminal emotional priming experiment paradigm. The results indicated that earthquake-exposed high school students had shorter reaction times to fearful faces and longer to happy faces than to neutral faces followed treat priming stimuli. Meanwhile, both earthquake-exposed high school students and college students had shorter reaction times to fearful faces than the non-exposed group followed treat priming stimuli, with significant N1, P1, P2and LPC effect to fearful faces. Obviously, the earthquake-exposed groups were more sensitive to fearful faces after the treat stimuli priming. However, could we change their emotional function with some cognitive and neural physiological training? Study7did this. The fourth part (Study7) was the research on neural plasticity of cognitive and brain function repair in earthquake-exposed survivors. From Study5and Study6, traumatic experiences influenced the emotional function of earthquake-exposed survivors, and enhanced the sensitivity to negative emotions. Thus, Study7developed an exploratory research on application of the principle of neural plasticity in brain function repair, which took the biofeedback training to adjust anxiety in earthquake-exposed survivors as an example. The results showed that the biofeedback training could effectively relieve negative emotion of earthquake-exposed survivors. It proved that the neural plasticity have effect on cognition and brain function repair through the brain electrical index, which also provided the foundation and possibility through physical intervention and treatment to change psychological and behavioral problems of earthquake-exposed survivors.(2) The neurophysiology mechanism of post-traumatic stress reaction in different age of earthquake-exposed survivors (high school students and college students).The research on Post-traumatic stress disorder suggested that the age was a very important risk factor. Especially the younger, they are more prone to PTSD. Therefore, the current research compared the neurophysiology mechanism of attention bias, memory bias, emotional cognitive processing in different age groups. In Study1and Study2, the results of behavior and an early P1component revealed that earthquake-exposed high school students were more vigilance for threat than earthquake-exposed college students. In Study3, neutral target stimuli elicited smaller P300amplitude in earthquake-exposed high school students compared with earthquake-exposed college students. In Study4, old earthquake stimuli elicited an earlier P3latency and enhanced P3and LPC amplitudes in earthquake-exposed high school students compared with in earthquake-exposed college students. In Study5and Study6, the behavioral and ERP (N1and P1components) results showed that the threat priming effect had greater impact on the emotional processing of high school students than on college students. Particularly, earthquake-exposed high school students were more sensitive to emotion than earthquake-exposed college students, especially for the negative emotion. The results suggested that the traumatic experiences had greater influence for earthquake-exposed high school students, which may be attributed to the brain and cognitive development of high school students.According to all of the studies above, we found that earthquake-exposed survivors’ mental and behavioral activities were based on cooperating with all parts of brain. Thus, we finally constructed the Post-Traumatic Stress Reaction Cooperation Cognitive Model (PTSR-CCM) based on the cognitive processing to earthquake treat stimuli in earthquake-exposed survivors. PTSR-CCM is the model of representing cognitive processing characteristics to earthquake treat stimuli in earthquake-exposed survivors. It includes three modules and a principle:attention function, memory function, emotion processing function, and neural plasticity, which revealed the threat stimuli effect on neurophysiology mechanism of post-traumatic stress reaction in the non-clinical earthquake-exposed survivors.更多还原