Connecting Brain and Behavior in the Very Brief Exposure Effect

描述(申请人提供)：拟议研究的目标是对恐惧可以在没有意识到的情况下减少这一假设进行迄今为止最严格的测试。两个实验将从大脑和行为方面检验这一假设，以调查无意识减少恐惧的新过程及其潜在的实用价值。这一假说挑战了主流的临床观念，即一个令人畏惧的物体必须直接面对全意识，以减少对它的恐惧。实验范式，非常短暂的曝光，由一系列连续的向后掩蔽的恐惧症图像组成(每一张持续33毫秒)。一系列实验表明，VBE减少对恐惧对象的回避(Siegel，Anderson&han，2011；Weinberger，等，2011；Siegel&Weinberger，2009)，比对相同刺激的清晰可见暴露(CVE，2012)更多(Siegel&Weinberger，2012)，并且减少回避的效果至少持续一年(Siegel&Warren，印刷中)。设计了功能磁共振成像和行为实验，以确定VBE的学习机制，并将它们与其对恐怖回避的影响联系起来。这项功能磁共振实验将在纽约州精神病研究所的磁共振实验室进行。26名蜘蛛恐惧症参与者和26名非恐惧症参与者将从购买学院/纽约州立大学的文科和理科课程中招募，他们将使用广泛使用的问卷、行为回避测试(BAT)和结构化临床面试进行DSM-IV诊断。三种类型的曝光都将在受试者内部进行：非常简短(33.4毫秒)和清晰可见(119毫秒)的蜘蛛图像，以及非常简短的花朵图像(对照)。主观恐惧在整个过程中都会定期进行评级。在缺乏恐惧体验的情况下，VBE被认为会习惯性地激活杏仁核，而CVE则不会习惯性地产生恐惧反应并引发主观恐惧。行为实验将在纽约州立大学佩奇学院的首席研究员实验室进行。80名蜘蛛恐惧症参与者-26名来自fMRI实验，74名其他人-将以同样的方式招募。根据避免活狼蛛的基线水平，他们将被随机分配给暴露于蜘蛛或花朵的非常简短(33ms)图像(对照组)。这些暴露将每连续三周进行一次，然后在活体内暴露于一只活的狼蛛。主观恐惧将在这些暴露之前和之后进行测量。在功能磁共振实验中，VBE减少杏仁核的激活将预测减少对狼蛛的回避。VBE将减少在第一次治疗后避免活狼蛛的发生。对照组参与者在第三次活体暴露前不会获得同样的收益。随后的两个VBE会议将带来进一步的收益。拟议的研究将为R01提案奠定基础，该提案旨在进一步研究非常短暂暴露的神经生物学机制，并测试其对临床人群的影响。

DESCRIPTION (provided by applicant): The goal of the proposed research is to conduct the strictest test to date of the hypothesis that fear can be reduced without awareness. Two experiments will test this hypothesis with respect to brain and behavior in order to investigate novel processes of non-conscious fear reduction and their potential practical utility. This hypothesis challenges the prevailing clinical belief that a feared object must be directly confronted with full awareness in order to reduce fear of it. The experimental paradigm, very brief exposure, consists of a continuous series of backward masked phobic images (each for duration of 33-ms). A series of experiments has shown that VBE reduces avoidance of a feared object (Siegel, Anderson & Han, 2011; Weinberger, et al., 2011; Siegel & Weinberger, 2009), more than clearly visible exposure (CVE) to the same stimuli does (Siegel & Weinberger, 2012), and that the avoidance- reducing effect lasts for at least a year (Siegel & Warren, in press). An fMRI and behavioral experiment are designed to identify the learning mechanisms of VBE and link them to its effect on phobic avoidance. The fMRI experiment will be conducted at the MRI Laboratory of the New York State Psychiatric Institute. Twenty-six spider-phobic and twenty-six non-phobic participants will be recruited from liberal arts and science courses at Purchase College/SUNY with a widely used questionnaire, a Behavioral Avoidance Test (BAT), and the Structured Clinical Interview for DSM-IV Diagnosis. Each of three types of exposure will be administered within-subjects: very brief (33.4-ms SOA) and clearly visible (119-ms SOA) images of spiders, and very brief images of flowers (control). Subjective fear is rated periodically throughout. VBE is expected to habituate amygdala activation in the absence of the experience of fear, whereas CVE will not habituate fear responses and induce subjective fear. The behavioral experiment will be conducted in the Principal Investigator's lab at Purchase College/SUNY. 80 spider-phobic participants - 26 from the fMRI experiment, and 74 others - will be recruited in the same manner. Based on baseline levels of avoidance of a live tarantula, they will be randomly assigned to exposure to very brief (33-ms SOA) images of either spiders or flowers (control group). These exposures will be administered each of three consecutive weeks, followed by in vivo exposure to a live tarantula. Subjective fear will be measured just before and after these exposures. Reduction of amygdala activation by VBE in the fMRI experiment will predict reduction of avoidance of the tarantula. VBE will reduce avoidance of a live tarantula after the first session. Control participants will not make the same gain until the 3rd session of n vivo exposure. The two subsequent VBE sessions will result in further gains. The proposed research will lay the groundwork for an R01 Proposal to further investigate neurobiological mechanisms of very brief exposure and test its effects on clinical populations.