Name: disrupting reconsolidation of fear memory in humans by a noradrenergic β-blocker
Uploaded: 2014-12-18T14:00:00.000+00:00
Duration: 8 min 32 s
Description: Watch this Scientific Journal Video about Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic ÃŽÂ²-Blocker at JoVE.com

这项工作是由荷兰科学研究组织一个VICI资助（梅雷尔·金特）的支持。

伦理学声明:我们的医师认可的协议符合心理学系的阿姆斯特丹大学的伦理委员会的测试人类参与者的要求。 1.附件的恐惧增强惊吓与冲击电极的<ol><li>保证了实验的设置包括了声音衰减参与者的房间和一个分离实验者房间。 </li><li>使用两台计算机四个屏幕，用于记录和监测的生理反应以及用于呈现实验脚本给与会者。 </li><li>附加双面胶衣领到EMG电极。 </li><li>清洁以下右眼或左眼和用酒精棉签额头参与者的皮肤。指示参与者保持自己的眼睛闭上，以避免潜在的眼睛刺激。 </li><li>填写肌电图电极与高导电的电解质GE中心升用注射器。不要试图通过施加少量凝胶的连续，因为这增加了凝胶内的空气的气泡，这可能会影响记录不利的风险以填充电极。 </li><li>下面附上与向前凝视，瞳孔中的行权或左眼的下眼睑的肌电电极之一。附第二个约1 - 2厘米横向于第一以下下睑的曲率。附上约为1厘米以下的发际线的前额接地参考。电极相对于肌肉的最佳位置可能需要个别调整。 </li><li>滴一滴导电胶的冲击电极和连接它们使用尼龙搭扣带左上方手腕。确保肩带是不是太紧。 </li><li>调整的2毫秒电击用于单独每个参与者的强度。通知震荡应该是"不舒服，但不痛"的参与者。 </li><li>手册LY引发震荡。开始在1mA的强度和持续触发单震荡 - 逐渐增加的强度在2或3毫安增量 - 直到参与者指示休克"不舒服，但不痛"。 </li><li>写下最后的冲击水平，保持整个实验的剩余这个水平。 </li></ol> 2.恐惧收购 - 第1天 持续时间约45分钟。 <ol><li>指导有关震荡的交付和盐酸普萘洛尔的可能管理的参与者。而且告诉他们，盐酸普萘洛尔，用于治疗高血压。获得书面知情同意书。 </li><li>屏幕对他们的健康，而且将禁忌表明服用40毫克的盐酸普萘洛尔的单剂量任何条件的参与者:怀孕，癫痫症，呼吸系统疾病，心血管系统疾病，在一线亲戚心血管疾病，直径betes，肝或肾疾病，目前使用的抗抑郁药，或精神病。 </li><li>获得使用电子血压计的血压和心脏速率的测量。要求参与者从袖子删除其手臂，把充气袖口安全上臂。指导参与者放松，坐下来与他们的手臂稍微弯曲在同一水平作为自己的心脏和一个桌子或其他平面上舒适的休息。 BP应该高于90/60毫米汞柱和心脏率超过60 BPM列入实验。 </li><li>管理状态-特质焦虑量 ​​表44和焦虑敏感指数45时，参与者在医学上被清除。使用蜘蛛作为条件刺激的照片时也管理蜘蛛恐怖性问卷46。 </li><li>定位参与者在电脑屏幕前，并附加了EMG和冲击电极（见恐惧增强惊吓的第1条"附件ð冲击电极"）。 </li><li>使用两种不同的学习方法 - 见步骤2.6.1和2.6.2。告诉参与者对两种不同的画面，他们会在电脑屏幕上看到。指示他们监视他们所看到的图像，并且当受到过冲击之间的关系。 <ol><li> 非渐近学习: 通知与会者，图片中的一个之后，将电击在大多数情况下，而其他将永远不会被随后震荡。 </li><li> 渐近学习:通知两张图片中，将始终遵循的电击以及画面将永远不会被随后震荡参与者（ 即指示害怕学习）。 </li></ol></li><li>告诉参与者的大声喧哗，他们会听到通过耳机。责令其不注意的噪音。 </li><li>指导参与者报告触电杜里的预期通过使用鼠标，并在5秒以下刺激发病推，以鼠标左键，以确认他们的预期移动光标连续评定量表纳克所有图片的呈现。确保尺度由11点从"肯定没有触电"到"不确定"标记为"肯定触电"。为了支持参与者将注意力集中在照片上连续地存在的秤在计算机屏幕的底部。当画面中消失，光标会自动返回到"不确定"的位置。 </li><li>直接参与者，以保持他们的眼睛在屏幕上，坐在静止地用双臂放置在一个轻松的位置与手腕了桌子上摆在他们面前。戴上耳机。昏暗的灯光，并关上了门。开始从其他房间的实验。 </li><li>在恐惧收购两幅图片中的一个合作终止与休克:CS1，而另一种是从未后跟冲击:CS 2。使以加强收购期间的恐惧协会使用恐惧相关的刺激。蜘蛛实例图片:IAPS号1200至1201年。 </li><li>呈现两个CS1和CS2为8秒。大声喧哗或惊吓探头 - 40毫秒，104分贝 - 都7秒CS发病后;并为CS1，这些在后面的是2毫秒电击500毫秒后。 </li><li>开始实际的恐惧呈现10基线惊跳探头减少初始惊恐反应性学习: <ol><li> 非渐近学习:出示总共上的75％的加固方案8 CS1试验:6 CS1试验是由休克增强-第一个和第五试验是未增强。而且目前8 CS2试验以及在跨试间隔8 NA试验。 </li><li> 渐近学习:目前共3 CS1试验在100％加固方案:所有的CS1试验都是R由冲击einforced。而且目前3 CS2试验以及3噪音惊吓独自在闭会期间试间隔探针（NA）。 </li></ol></li><li>平衡的图片作为CS1和CS2跨越参与者的分配。随机试验类型CS1的块中的顺序 - CS2 - NA，使得没有试验型重复两次以上。改变跨试间隔 - 在此期间，与会者观看黑屏 - 15秒，20秒和25秒，平均20秒之间。 </li><li>在实验结束后分离电极和让参与者清理关闭的凝胶。 </li><li>指导参与者判断的冲击11点量表，从零下 5（ 即不愉快的）到5（ 即可人）的愉悦。 </li><li>明确指示参与者要记住他们所恐惧收购过程中，为了增加保留CS-美国应急了解到随后的日子里，以及以防止它们在后续的测试错误地期待一个不同的应变方案。此外，第二天促进唾液样本，指导参与者从锻炼咖啡因和酒精的12小时期间，以避免和避免的食物和饮料比水以及吸烟和牙齿的2小时期间刷牙其他之前下一会话。 </li><li>清洁电极彻底使用后的水:摆脱所有凝胶而不刮伤氯化银层的任何部分。清洗后没有擦去水，但使用不同的一组电极上的下一交易参加者，并允许另一组干随着时间的推移。 </li></ol> 3.内存重新激活 - 第2天 约105分钟的持续时间。 <ol><li>随机指定参与者任普萘洛尔盐酸或安慰剂丸条件与该条件相匹配，在给定的焦虑分数尽可能接近所述限制该性状anxietŸ决定破坏再巩固47的恐惧减少的影响。使用蜘蛛作为条件刺激的照片时匹配SPQ分数参与者为好。 </li><li>获得血压和心脏率测量以及唾液样品:指导参与者只需把含在嘴里的棉签约3分钟。保持Salivettes在零下 25℃后取出。 </li><li>对于普萘洛尔没有激活状态转到步骤4.8.1。 </li><li>定位参与者在电脑屏幕前，并附加了EMG和冲击电极（见 第1节"的恐惧增强惊吓与冲击电极的附件"）。报告参与者的冲击力度将保持不变。 </li><li>通知与会者，两个相同的画面会在计算机屏幕上呈现，并要求他们记住他们前一天得知 - 图片之一AGA会在随后的电击或者大多数 （ 即非渐进的学习）或全部 （ 即渐进的学习，）的情况下，而其他将永远不会被随后震荡。指导参与者的所有照​​片的演示过程中报告触电的预期。戴上耳机，并调暗灯光。关上门，开始从其他房间的实验。 </li><li>首先介绍10基线惊跳探头以减少初期惊恐反应的记忆重新激活。接下来提出一个单一的无筋CS1审判后跟单个NA审判。 </li><li>分离从实验装置的与会者，并让他们清理关闭的凝胶。他们坐其他的桌子后面。 </li><li>管理"双盲"安慰剂药片或40毫克盐酸普萘洛尔的口服剂量。丸应该由药房或同事的独立研究的蒙蔽。随叫随到的进一步医生的协议我的知识被认为是在给药后必要的。 <ol><li>管理"单盲"的40毫克盐酸普萘洛尔为普萘洛尔没有激活状态的口服剂量。 </li></ol></li><li>插入的约90分钟的休息时间。提供参与者的杂志阅读。清洗在其间的电极。 </li><li>再次获得BP和心脏率测量以及唾液样品。 </li></ol> 4.测试 - 第3天 持续时间约45分钟。 <ol><li>获得BP和心脏率测量。 </li><li>定位参与者在电脑屏幕前，并附加了EMG和冲击电极。报告再次向与会的冲击力度将保持不变。 </li><li>指示，相同的两个图片将在计算机屏幕上显示的参加者。再次指示与会的所有画面的演示过程中报告触电的预期秒。戴上耳机，并调暗灯光。关上门，开始从其他房间的实验。 </li><li>通过展示10基线惊跳探头开始实验。在灭绝目前约12无筋CS1和CS2试验以及12 NA试验。灭绝后，参与者得到三个unsignaled USS:复职。再次出现的参与者约4无筋CS1和CS2试验以及4 NA试验继unsignaled USS:恢复测试。 </li><li>分离电极，让参与者清理掉凝胶。付参与者少量用于其在实验中的参与。清洁电极用水彻底。 </li></ol>

作者什么都没有透露。

在一系列研究中，我们一再反映，不论男女，40毫克的去甲肾上腺素能β受体阻滞剂普萘洛尔无论之前或之后的内存重新给予有效的中和条件性恐惧反应（ 即防御惊吓反应）。没有这四个机制复发的-恢复，重建，自发恢复和快速重捕获-破坏再巩固与普萘洛尔27-32,37-39后观察。值得注意的是，在恐惧中和效果进行仅观察到防守惊恐反应，但既不为威胁的预期等级也不对皮肤电导。用于皮肤电调节的数据不被这里报告作为一般图形的可控硅未显著从预期的评分偏离。在人类恐惧条件的研究，条件多指数响应（ 如 ，美国的预期，SCR，惊跳ř反应的影响，瞳孔扩大，神经活性）为交叉验证48的原 ​​因，通常获得的。然而，现在有令人信服的证据表明，这些不同的响应水平不一定采取一致行动，并且甚至可能彼此3,27-32,34,37,49离解。注意，惊恐反应是一个自动防御反射，这是增效响应于一个与负价的美国相关联，并且通常不能与USS的中性或正价49,50（ 例如 ，振动触觉刺激或观察的CS反应时间任务）。因此，在防守惊跳反射的增强作用是厌 ​​恶空调34的可靠和特定索引。与此相反，可控硅调理可以发生而不考虑美国49,50的价数。考虑到美国的情感价不修改可控硅，皮肤电调理预期觉醒的非特定的措施。因此，我们认为，这个SCR是以下Suited作为衡量行为人厌恶空调的研究。 如果我们猜测将这些成果转化为临床实践中，一些问题和潜在的限制是必须考虑的。首先，它可能有疑问的药理操纵由去甲肾上腺素能β受体阻滞剂是否真的必要破坏的再固结或是否一个行为过程旨在​​干扰再固结将产生类似的中和作用的过程。即使普萘洛尔的低剂量的一会话治疗显然是无毒的，完全的行为过程总是优选超过一个药物干预。的确，其中消光训练再固结51的窗口内呈现的另一种方法。然而，一些研究未能席勒等人 29,52-54复制这些最新发现却看到55,56。除了这些相互矛盾的结果，一个内再活化过程的消光的其他潜在限制将是，在临床实践中的恐惧反应通常不是在一会话曝光处理熄灭。例如，对于患者的创伤后应激障碍虚接触传统需要10届恐惧消退57之前。因此，即使承认在比较完全的行为干预的简单的药理学治疗的明显的缺点，我们认为，在去甲肾上腺素能操纵存储器再固结似乎比所述再固结窗口内的消光更加可行。 第二个问题是关于最佳条件来触发记忆再巩固。有越来越多的证据表明，调解恐惧的行为表达机制，明确从中介再巩固31,32,58-62的过程机制分离。例如，最近的动物研究发现了差分和离解řeceptors在基底外侧杏仁核调解以前条件性恐惧的回忆63,64的表达，不稳定和重新稳定。恐惧记忆的行为表达，不仅从工艺调解记忆激活（ 即访问记忆痕迹）分离，似乎也不能成为必不可少的再巩固发生63。因此，在恐惧记忆激活的表达是不是对信息的记忆痕迹是否进入一个不稳定的阶段。鉴于存储器不稳定对于去甲肾上腺素β受体阻滞剂干扰重新稳定过程的一个先决条件，一个重要的问题是如何能在临床实践中推断成功存储器不稳定。主机的调查结果表明，在诱导再巩固和无论从内存中提取，或一个新的内存40,65的整合划分再巩固一个关键因素是预测误差在mem的诱导程度ORY检索31,32。但鉴于没有客观的标准可用来确定在临床实践中的预测误差的最佳程度，目前的实验室研究结果不能容易地转化为治疗方案。 对翻译文学神经科学到临床实践中面临的另一个挑战是关于范式的生态效度。该证据用于破坏再固结已经主要示于动物和人类对相对较新的（一天龄）和简单的恐惧记忆（ 即 ，音调休克;图象休克）。这是不言自明，因为它已经在实验室进行线索恐惧制约已经表明，破坏旧的，更强大和更广泛的存储网络，再巩固，如患者的创伤后应激障碍是有效的。同时相对于因变量，目前还不清楚来自动物和人类实验研究中观察是否推广到患者的焦虑症。害怕再ducing影响迄今主要表现为厌恶空调的行为表现（ 即冻结在啮齿类动物或人类的防御惊吓反射行为），只有一个例外，我们证明了困扰也是主观感受是显著由去甲肾上腺素能阻断中性记忆再巩固37。它可以被质疑在实验室，这些恐惧还原效果是否表明焦虑症患者的恐惧和回避行为特征的典型经验。未来的研究应调查目前的研究结果是否真的推广到回避行为，焦虑症的核心症状之一。 总之，虽然巴甫洛夫厌恶空调的过程是学习的恐惧学习和记忆的基本机制的一个很好的工具，我们不能轻易转化实验室成果转化为临床实践。我们小时的见解AVE被获取对最优，边界和存储器再固结必要条件应仅被视为起点的再固结为基础的治疗的发展。另一方面，在消光训练的广泛研究已导致消光系曝光的干预，这仍属于最有效的治疗焦虑症和其他相关病症。由于记忆再巩固的去甲肾上腺素能阻滞剂掩盖了灭绝学习的抗焦虑作用，破坏再巩固指向一个有前途的新的干预措施，以有效地减少过度和非理性的恐惧。

我们的大脑编程学习。人类都配备学习生活中的潜在危险，甚至更重要的是学会了危险的预测能力。巴甫洛夫厌恶空调是研究关联恐惧学习，不仅在人类中也跨越多种生物1,2的一个很好的工具。此过程涉及呈现一种无害的生物中性条件刺激（CS， 如铃声或图片）与有毒，有害非条件刺激（US），通常是温和的电击。如果CS成为美国的一个可靠的预测中，CS将引起物种典型条件的行为反应（ 例如 ，冻结在大鼠和增效在人类惊跳反射），其概念化为恐惧表达式（见3有关此批评术语）。不仅厌恶空调研究添加到一个更好的理解的分子和细胞的缔恐惧学习和记忆4的流程，但它也提供了用于理解焦虑症5的病因和过程的基础。虽然它承担提的是焦虑症不一定直接调节经验，如创伤性事件的结果。他们也可能导致间接或替代害怕学习经历6。但不论学习历史，联想恐惧记忆就在于在焦虑症的核心。在巴甫洛夫条件反射范式不仅证明了其效用在了解焦虑症的起源，这也是一个很好的翻译模型来开发和推进的治疗焦虑症5。 在实验室中研究最广泛的两个程序，以减少了解到恐惧是:（1）灭绝和再巩固的（2）中断。尽管消退训练- 即反复无钢筋再次接触在CS 7,8 -是一种有效的抗焦虑战略，动物和人类的恐惧条件可靠的研究表明，空调的恐惧反应可通过重新接触unsignaled USS（ 即恢复），上下文的变化（ 即更新）轻松地返回，或时间的推移（ 即自发恢复）7,9,10。共识已经建立了灭绝学习不删除原有的恐惧记忆，而是反映了一种新的抑制记忆的形成。其结果是，在恐惧记忆可以复出导致即使在最初成功的恐惧消退回报的恐惧。复发的各种来源仍是临床实践的一个重大挑战。 另一种方法，以减少条件性恐惧响应是最近（重新）发现的药理学试剂破坏存储器再固结的过程。这个过程是非常有前途的，因为它不仅削弱conditio奈德恐惧响应，但它甚至似乎擦除缔恐惧记忆，这可能会最终解决复发的问题。 存储器再固结是指两相过程，其中先前合并存储器转移到一个瞬态不稳定状态，在检索和需要的时间依赖重新稳定持续至14-18。基因转录，蛋白和RNA的合成所必需的这一重新稳定，并提供机会遗忘剂影响恐惧记忆的一个窗口。失忆的了解到恐惧已经被证明在动物用药物（ 如茴香）目标所需的蛋白质合成14,19,20和21,22的神经递质的释放。蛋白质的合成，也可以由去甲肾上腺素能β受体阻滞剂心得安，这是为了抑制去甲肾上腺素刺激CREB磷酸23-25 ​​干扰。恐惧降低普萘洛尔的影响已被证明在动物和人类26-32。在一系列歧视性的恐惧调节的研究中，我们始终表明，心得安（40毫克）之前或之后的内存重新给予有效降低了空调的惊吓恐惧反应，并阻止恐惧在健康的参与者的回报。 原理的证明 在我们人类的恐惧调节的研究用在破坏再巩固的基本设计包括测试过跨连续三天不同的阶段，至少24小时，以分离（1）支持（重新）合并的记忆和（2）允许药物测试前洗出。第1天- 恐惧采集阶段，健康参与者暴露于一系列图像演示。一幅画的刺激（CS1 +）反复搭配的厌恶电刺激（美国），导致收购的恐惧协会，而另一张照片的刺激（CS2-）从不后跟一个美国。第2天- 记忆激活阶段，重新暴露在无筋条件刺激（CS1-）通常触发条件恐惧反应。在这个阶段中，我们系统地施用40毫克盐酸普萘洛尔，一个β肾上腺素受体 ​​拮抗剂，间接靶向所需再固结25的蛋白质的合成。鉴于普萘洛尔33的血药峰浓度，我们给予之前在我们的第一个实验中的恐惧记忆的重新普萘洛尔90分钟口服剂量。然而，对于再固结的一个更优化的试验中，遗忘剂应的存储器的重新激活之后给药。因此，在我们的实验后，我们一直服用普萘洛尔后重新内存具有非常相似的结果。在第3天-在测试阶段，恐惧记忆的保持被干预后测试24小时（ 即 ，第一测试试验第3天），随后消光 过程和情景触发，以测试恐惧的回报（ 即恢复，重建，自然恢复，快速重捕）。用于确定普萘洛尔的效果是否需要恐惧记忆活性检索，该药物应给予另一恐惧空调组而不存储器（ 即 ，普萘洛尔无活化条件）27,28的再活化。我们使用惊跳反射的增强，作为条件恐惧反应和美国在线的预期收视率作为指标应急学习的​​措施。惊跳反射的增强被认为是恐惧34，具体的，可靠的指数扁桃体35升任。最常用的惊吓-引发刺激是"惊跳探针"，即通过耳机中的刺激或两种刺激演示之间的间隔给出一个响亮的噪声（ 即 ，intertrial间隔） <suP&gt; 36。恐惧条件刺激（CS1 +）为与对照相比的刺激（CS2-）期间更强惊恐反应的巨响反射由担心刺激（CS1 +）引发的参与者的可怕状态。 在一系列的连续10实验独立样本27-32,37-39中，我们始终复制我们原来的发现，其中由β-肾上腺素能受体阻滞剂普萘洛尔破坏恐惧记忆再巩固盐酸有效降低了空调的惊跳反射和防止恐惧27回。观察暴露于初级强化（ 即恢复），在上下文中的变化（ 即更新）或时间（ 即自然恢复）简单的流逝并没有导致重新出现条件性恐惧反应的一般观察灭绝训练后，支持破坏再巩固了灭绝学习的优越性。除了这些检索技术，重新获得学习没有透露以前学过的恐惧反应的任何积蓄。总之，这些研究结果表明，通过普萘洛尔打乱了联想恐惧记忆再巩固有效减少恐惧记忆的情感表达。 此外，我们还测试了几个边界和破坏再巩固的必要条件:（1）内存激活会话似乎在程序上类似于灭绝培训（ 即非增强曝光），但它应该涉及比灭绝的训练，因为去甲肾上腺素能β受体阻滞剂少无筋试验（ 即 ，心得安），也可能干扰灭绝内存，而不是针对原来的恐惧记忆40,41的形成; （2）存储器检索是不足够的存储器再固结18,31,42,43。普萘洛尔不仅减少了空调的恐惧，因为当时有检索SESS期间学到了一些东西响应离子31,32。之间有什么已经学到什么可以在一个给定的检索会话教训（ 即预测误差）似乎是一个差异是必要的诱导联想恐惧记忆再巩固32。结果表明，预测误差的发生是一个必要条件，再固结，并为开发和优化再固结为基础的治疗的患者的焦虑症患的有用工具。

<table><tbody><tr><td>2 computers with 4 screens</td><td>Dell</td><td>Optiplex 9010</td><td>Recording and monitoring physiological responses. Presenting the experimental script.&amp;nbsp;</td></tr><tr><td>Amplifier</td><td>Developed by B. Molenkamp - University of Amsterdam</td><td></td><td>Designed around a Burr Brown INA101 amplifier and ISO103 isolation stage.&amp;nbsp;</td></tr><tr><td>VSSRP98&amp;nbsp;</td><td>Developed by B. Molenkamp - University of Amsterdam</td><td></td><td>Physiological registration software. Record electromyography - EMG - activity using a bundled pair of electrodes wires connected to a front-end amplifier with an imput resistacne of 10 M&amp;Omega; and a bandwidth of DC-1500 Hz. Raw EMG signals are integrated in the amplifier. Integrated EMG signals are sampled at 1,000 Hz and used for data analysis.</td></tr><tr><td>MATLAB</td><td>MathWorks</td><td></td><td>Analyzing data. Peak amplitudes are determined by taking the baseline 50 msec before probe onset to peak differences within 30 - 150 msec following probe onset and are recorded in microvolt.</td></tr><tr><td>Presentation</td><td>NeuroBehavioral Systems Inc. - USA</td><td></td><td>Stimulus presentation.</td></tr><tr><td>&lt;a href=&quot;http://digitimer.com/products/clinical-neurophysiology/ds7aah-psarp-peripheral-stimulators/&quot; target=&quot;_blank&quot;&gt;Constant current stimulator&lt;/a&gt;</td><td><a href="http://www.digitimer.com" target="_blank"><img src="/img/new_window.png" /> Digitimer Ltd.</a></td><td>&lt;a href=&quot;http://digitimer.com/products/clinical-neurophysiology/ds7aah-psarp-peripheral-stimulators/ds7a-ds7ah-hv-constant-current-stimulator-clinical-product/&quot; target=&quot;_blank&quot;&gt;DS7A&lt;/a&gt;</td><td>Generates electrical stimulation</td></tr><tr><td>Shock electrodes</td><td>Made by B. Molenkamp - University of Amsterdam</td><td></td><td>Ag electrodes of 20 mm x 25 mm with fixed inter-electrodes mid-distance of 45 mm.</td></tr><tr><td>Headphones</td><td>Sennheiser Electronic GmbH &amp;amp; CO - Germany</td><td>HD 25-1 II</td><td>Presentation of startle probse and background noises.</td></tr><tr><td>EMG electrodes</td><td>Made by B. Molenkamp - University of Amsterdam</td><td></td><td>Three 7 mm sintered Ag-AgCl electrodes.</td></tr><tr><td>Double-sided adhesive collars</td><td>MedCaT - the Netherlands</td><td>848125</td><td>13 mm x 5 mm. For attaching the EMG electrodes to the skin.</td></tr><tr><td>Conductive gel</td><td>Signa Gel - Parker Laboratories Inc. - USA&amp;nbsp;</td><td>224.550.011</td><td>Facilitates conduction from the skin to both the EMG and shock electrodes.</td></tr><tr><td>Alcohol swabs&amp;nbsp;</td><td>Sanadep 0.5% - Microtek Medical - the Netherlands</td><td>3053800</td><td>For cleaning the skin of the participant.</td></tr><tr><td colspan="4">[header]</td></tr><tr><td>Sphygmomanometer</td><td>Omron Healthcare Europe B.V. - the Netherlands</td><td>M4-I HEM-752-E</td><td>Measuring blood pressures and heart rate.</td></tr><tr><td>Cotton salivettes</td><td>Sarstedt - Germany</td><td>511.534</td><td>Obtaining salivary samples.</td></tr><tr><td>Curved tip syringe</td><td>Monoject - Covidien - USA</td><td>412</td><td>Applies gel to EMG and shock electrodes.</td></tr><tr><td>Propranolol HCl - 40 mg and placebo pills&amp;nbsp;</td><td>Huygens Apotheek - the Netherlands</td><td></td><td>Pills should be identical in exterior.</td></tr></tbody></table>

disrupting reconsolidation of fear memory in humans by a noradrenergic &#946;-blocker

在我们人类的恐惧调节的研究用在破坏再巩固的基本设计包括测试过跨连续三天不同的阶段。第1天- 恐惧采集阶段，健康参与者暴露于一系列图像演示。一个画面的刺激（CS1 +）重复配对厌恶电刺激（US），从而导致在获得一个恐惧关联的，而另一图像刺激（CS2-）从不后跟一个美国。第2天- 存储器活化阶段，参与者被重新暴露于没有美国（CS1-），其通常触发条件恐惧反应的条件刺激。存储器激活之后，我们给予的盐酸普萘洛尔，一个β肾上腺素受体拮抗剂通过抑制去甲肾上腺素刺激CREB磷酸间接靶向所需再固结的蛋白质合成的40毫克的口服剂量。在第3天 - 在测试阶段中，participants在为了测量操纵的恐惧降低效果再次暴露于未增强条件刺激（CS1-和CS2-）。此滞留试验后的消光的过程和情景触发的呈现来测试恐惧的回报。的眨眼惊跳反射的增强作用被测量作为指标为条件性恐惧响应。恐惧协会的陈述性知识是通过每个CS演示过程中，美国在线的预期收视率测量。相反灭绝学习，扰乱再巩固的目标原来恐惧记忆从而防止恐惧的回报。虽然临床应用仍处于起步阶段，破坏恐惧记忆再巩固似乎是一个有前途的新技术的前景，坚持抑制患者的焦虑症和其他精神障碍患者恐惧记忆的表达。

操纵检查普萘洛尔:相反丸安慰剂，无论是收缩压和舒张压以及唾液的α-淀粉酶应在存储器再活化，这表明该药物操纵施加其预期的生理效应的普萘洛尔摄取后减少90分钟。 BP和唾液淀粉酶的α应该重新回归到基线水平在测试第3天。 我们预期评级:随着当前协议，你可能没有想到对美国的预期收视率普萘洛尔治疗的任何影响。不考虑药物治疗，差美国收视率的预期应该恐惧收购过程中增加和灭绝后学习 48小时期间减少。此外，该unsignaled USS的表现预计将导致回报率差的预期收视率（ 图1A-C）的。 <str翁&gt;前提条件的再巩固:为了触发再巩固的过程，记忆痕迹应首先将不稳定的必要条件重新稳定阶段。对于恐惧记忆不稳定，在激活的瞬间威胁的预期（ 即完整的CS1-美国的预期）是必要的，虽然31并不足够。追求上再巩固的作用是更新记忆痕迹，以不断变化的环境的想法，记忆激活还应包括预测误差（PE:之间有什么预期和实际情况不匹配）。鉴于美国收视率的预期依然不受普萘洛尔操纵，改变预期的威胁，从收购到测试（PE）可作为内存不稳定（见第32的更多详细信息）的独立指标。但是，只有当内存重新遵循渐进的学习，这些变化在威胁预期马Ý被观察到。在的情况下部分地增强非渐近的学习，在威胁预期的换档是没有必要的存储器不稳定。因此，一个检索审判也可能引发再巩固，而不非渐进的学习后，预期的变化。 惊吓恐惧响应:在第1天成功恐惧获得证明通过增加差动惊恐恐惧响应（ 即 ， 相对于 CS1 CS2）从第一到采集（ 图1D-F），最后一个试验。较高的惊吓恐惧回应先前再加上冲击（CS1）相比，在第2天记忆激活单独的噪声刺激进一步表明恐惧记忆很好巩固。 在第3天的测试阶段，你可能希望完好无损惊吓恐惧，安慰剂组应答:惊跳响应CS1应为h<html> igher相比CS2在试验开始。消退训练之后降低差分惊吓 ​​响应（ 即 CS1 VS。CS2）。此外，该unsignaled USS的呈现应该导致返回恐惧响应CS1相比，CS 2（ 图1D）。 相反，安慰剂丸，盐酸普萘洛尔的管理预期导致淘汰的差异惊吓恐惧响应（ 即 CS1 与 CS2）在第3天的测试阶段的开始。此外，你可以期望unsignaled USS不会收回惊吓恐惧响应（ 图1E）。 需要注意的是心得安不应该有任何的恐惧还原效果时，丸给药无第2天（ 图1F）内存激活。 重1"SRC ="/文件/ ftp_upload / 52151 / 52151fig1highres.jpg"WIDTH ="700像素"/&gt; 图1.美国平均收视率的CS1和CS2试验和采集过程中惊吓恐惧反应的CS1，CS2和噪声单独（NA）试验，内存激活，灭绝和测试的安慰剂组（A，D），心得安（B， E）和普萘洛尔NO-激活（C，F）组 R-CS1 - 。是指未增强激活试用<a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/52151/52151fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic ÃŽÂ²-Blocker at JoVE.com

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic &#946;-Blocker

Disrupting reconsolidation is a promising approach to dampen the behavioral expression of fear memory in patients with anxiety disorders or posttraumatic stress disorder. In a series of human fear conditioning studies we showed that disrupting reconsolidation by the noradrenergic &#946;-blocker propranolol is very effective in erasing conditioned fear responding.

由去甲肾上腺素能β受体阻滞剂破坏恐惧记忆在人类再固结

The basic design used in our human fear-conditioning studies on disrupting reconsolidation includes testing over different phases across three consecutive ...

disrupting-reconsolidation-fear-memory-humans-noradrenergic

Universidad San Sebastian

Research

JoVE Journal

Behavior

22.8K 次观看.  University of Amsterdam. Disrupting reconsolidation is a promising approach to dampen the behavioral expression of fear memory in patients with anxiety disorders or posttraumatic stress disorder. In a series of human fear conditioning studies we showed that disrupting reconsolidation by the noradrenergic β-blocker propranolol is very effective in erasing conditioned fear responding. 

视频: Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic β-Blocker

Trace Fear Conditioning in Mice

In this experiment we present a technique to measure learning and memory. In the trace fear conditioning protocol presented here there are five pairings between a neutral stimulus and an unconditioned stimulus. There is a 20 sec trace period that separates each conditioning trial. On the following day freezing is measured during presentation of the conditioned stimulus (CS) and trace period. On the third day there is an 8 min test to measure contextual memory. The representative results are from mice that were presented with the aversive unconditioned stimulus (shock) compared to mice that received the tone presentations without the unconditioned stimulus. Trace fear conditioning has been successfully used to detect subtle learning and memory deficits and enhancements in mice that are not found with other fear conditioning methods. This type of fear conditioning is believed to be dependent upon connections between the medial prefrontal cortex and the hippocampus. One current controversy is whether this method is believed to be amygdala-independent. Therefore, other fear conditioning testing is needed to examine amygdala-dependent learning and memory effects, such as through the delay fear conditioning.

In the following experiment we describe a protocol for trace fear conditioning in mice. This type of associative memory includes a trace period that separates the neutral stimulus and the unconditioned stimulus.

跟踪恐惧条件小鼠

In this experiment we present a technique to measure learning and memory. In the trace fear conditioning protocol presented here there are five pairings ...

科研

行为学

Protocol for Studying Extinction of Conditioned Fear in Naturally Cycling Female Rats

Extinction of conditioned fear has been extensively studied in male rodents. Recently, there have been an increasing number of studies indicating that neural mechanisms for certain behavioral tasks and response behaviors are different in females and males. Using females in research studies can represent a challenge because of the variation of gonadal hormones during their estrous cycle. This protocol describes well-established procedures that are useful in investigating the role of estrogen in fear extinction memory consolidation in female rats. Phase of the estrous cycle and exogenous estrogen administration prior to extinction training can influence extinction recall 24 hr later. The vaginal swabbing technique for estrous phase identification described here aids the examination and manipulation of naturally cycling gonadal hormones. The use of this basic rodent model may further delineate the mechanisms by which estrogen can modulate fear extinction memory in females.

Gonadal hormones such as estrogen modulate memory formation in a number of experimental paradigms including fear extinction memory. This protocol describes a set of methods for investigating the influence of gonadal hormones specifically during extinction in naturally cycling females, including estrous cycle monitoring and exogenous estrogen administration.

协议在骑自行车自然雌性大鼠学习条件性恐惧灭绝

Extinction of conditioned fear has been extensively studied in male rodents. Recently, there have been an increasing number of studies indicating that ...

Quantifying Cognitive Decrements Caused by Cranial Radiotherapy

With the exception of survival, cognitive impairment stemming from the clinical management of cancer is a major factor dictating therapeutic outcome. For many patients afflicted with CNS and non-CNS malignancies, radiotherapy and chemotherapy offer the best options for disease control. These treatments however come at a cost, and nearly all cancer survivors (~11 million in the US alone as of 2006) incur some risk for developing cognitive dysfunction, with the most severe cases found in patients subjected to cranial radiotherapy (~200,000/yr) for the control of primary and metastatic brain tumors1. Particularly problematic are pediatric cases, whose long-term survival plagued with marked cognitive decrements results in significant socioeconomic burdens2. To date, there are still no satisfactory solutions to this significant clinical problem.
We have addressed this serious health concern using transplanted stem cells to combat radiation-induced cognitive decline in athymic rats subjected to cranial irradiation3. Details of the stereotaxic irradiation and the in vitro culturing and transplantation of human neural stem cells (hNSCs) can be found in our companion paper (Acharya et al., JoVE reference). Following irradiation and transplantation surgery, rats are then assessed for changes in cognition, grafted cell survival and expression of differentiation-specific markers 1 and 4-months after irradiation. To critically evaluate the success or failure of any potential intervention designed to ameliorate radiation-induced cognitive sequelae, a rigorous series of quantitative cognitive tasks must be performed. To accomplish this, we subject our animals to a suite of cognitive testing paradigms including novel place recognition, water maze, elevated plus maze and fear conditioning, in order to quantify hippocampal and non-hippocampal learning and memory. We have demonstrated the utility of these tests for quantifying specific types of cognitive decrements in irradiated animals, and used them to show that animals engrafted with hNSCs exhibit significant improvements in cognitive function3.
The cognitive benefits derived from engrafted human stem cells suggest that similar strategies may one day provide much needed clinical recourse to cancer survivors suffering from impaired cognition. Accordingly, we have provided written and visual documentation of the critical steps used in our cognitive testing paradigms to facilitate the translation of our promising results into the clinic.

Cognitive impairment resulting from the radiotherapeutic management of brain tumors represents a clinically intractable condition that adversely impacts quality of life. The capability to critically evaluate potential interventions for ameliorating radiation-induced cognitive decrements ultimately depends on the capability to undertake rigorous quantitative assessments of cognition.

量化颅放疗引起的认知递减

With the exception of survival, cognitive impairment stemming from the clinical management of cancer is a major factor dictating therapeutic outcome. For ...

医学

Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory.

Vagus nerve stimulation (VNS) has emerged as a tool to induce targeted synaptic plasticity in the forebrain to modify a range of behaviors. This protocol describes how to implement VNS to facilitate the consolidation of fear extinction memory.

迷走神经刺激作为一种工具来诱导可塑性相关途径灭绝学习

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been ...

Investigating the Neural Mechanisms of Aware and Unaware Fear Memory with fMRI

Pavlovian fear conditioning is often used in combination with functional magnetic resonance imaging (fMRI) in humans to investigate the neural substrates of associative learning 1-5. In these studies, it is important to provide behavioral evidence of conditioning to verify that differences in brain activity are learning-related and correlated with human behavior. 
Fear conditioning studies often monitor autonomic responses (e.g. skin conductance response; SCR) as an index of learning and memory 6-8. In addition, other behavioral measures can provide valuable information about the learning process and/or other cognitive functions that influence conditioning. For example, the impact unconditioned stimulus (UCS) expectancies have on the expression of the conditioned response (CR) and unconditioned response (UCR) has been a topic of interest in several recent studies 9-14. SCR and UCS expectancy measures have recently been used in conjunction with fMRI to investigate the neural substrates of aware and unaware fear learning and memory processes 15. Although these cognitive processes can be evaluated to some degree following the conditioning session, post-conditioning assessments cannot measure expectations on a trial-to-trial basis and are susceptible to interference and forgetting, as well as other factors that may distort results 16,17 .
Monitoring autonomic and behavioral responses simultaneously with fMRI provides a mechanism by which the neural substrates that mediate complex relationships between cognitive processes and behavioral/autonomic responses can be assessed. However, monitoring autonomic and behavioral responses in the MRI environment poses a number of practical problems. Specifically, 1) standard behavioral and physiological monitoring equipment is constructed of ferrous material that cannot be safely used near the MRI scanner, 2) when this equipment is placed outside of the MRI scanning chamber, the cables projecting to the subject can carry RF noise that produces artifacts in brain images, 3) artifacts can be produced within the skin conductance signal by switching gradients during scanning, 4) the fMRI signal produced by the motor demands of behavioral responses may need to be distinguished from activity related to the cognitive processes of interest. Each of these issues can be resolved with modifications to the setup of physiological monitoring equipment and additional data analysis procedures. Here we present a methodology to simultaneously monitor autonomic and behavioral responses during fMRI, and demonstrate the use of these methods to investigate aware and unaware memory processes during fear conditioning.

A methodology to investigate the neural mechanisms that support aware and unaware memory processes during fear conditioning is described. This method monitors blood oxygen level dependent (BOLD) functional magnetic resonance imaging, skin conductance response, and unconditioned stimulus expectancy during Pavlovian fear conditioning to assess the neural correlates of distinct memory processes.

调查的意识到，不知道用功能磁共振成像的恐惧记忆的神经机制

Pavlovian fear conditioning is often used in combination with functional magnetic resonance imaging (fMRI) in humans to investigate the neural substrates ...

神经科学

Extinction Training During the Reconsolidation Window Prevents Recovery of Fear

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents the return of fear. Pavlovian fear-conditioning paradigms are commonly employed to create a controlled, novel fear association in the laboratory. After pairing an innocuous stimulus (conditioned stimulus, CS) with an aversive outcome (unconditioned stimulus, US) we can elicit a fear response (conditioned response, or CR) by presenting just the stimulus alone1,2 . Once fear is acquired, it can be diminished using extinction training, whereby the conditioned stimulus is repeatedly presented without the aversive outcome until fear is no longer expressed3. This inhibitory learning creates a new, safe representation for the CS, which competes for expression with the original fear memory4. Although extinction is effective at inhibiting fear, it is not permanent. Fear can spontaneously recover with the passage of time. Exposure to stress or returning to the context of initial learning can also cause fear to resurface3,4.
Our protocol addresses the transient nature of extinction by targeting the reconsolidation window to modify emotional memory in a more permanent manner. Ample evidence suggests that reactivating a consolidated memory returns it to a labile state, during which the memory is again susceptible to interference5-9. This window of opportunity appears to open shortly after reactivation and close approximately 6hrs later5,11,16, although this may vary depending on the strength and age of the memory15. By allowing new information to incorporate into the original memory trace, this memory may be updated as it reconsolidates10,11. Studies involving non-human animals have successfully blocked the expression of fear memory by introducing pharmacological manipulations within the reconsolidation window, however, most agents used are either toxic to humans or show equivocal effects when used in human studies12-14. Our protocol addresses these challenges by offering an effective, yet non-invasive, behavioral manipulation that is safe for humans.
By prompting fear memory retrieval prior to extinction, we essentially trigger the reconsolidation process, allowing new safety information (i.e., extinction) to be incorporated while the fear memory is still susceptible to interference. A recent study employing this behavioral manipulation in rats has successfully blocked fear memory using these temporal parameters11. Additional studies in humans have demonstrated that introducing new information after the retrieval of previously consolidated motor16, episodic17, or declarative18 memories leads to interference with the original memory trace14. We outline below a novel protocol used to block fear recovery in humans.

Conditioned fear can be diminished through an inhibitory process called extinction, but can resurface under conditions such as the passage of time or exposure to stress. Our protocol presents a novel way of preventing fear recovery by introducing extinction during the reconsolidation window (the re-storage phase of a reactivated memory).

灭绝培训在彭兰霞窗口无法还原的恐惧

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents ...

Stress-Enhanced Fear Learning, a Robust Rodent Model of Post-Traumatic Stress Disorder

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders such as post-traumatic stress disorder (PTSD). To understand the biological mechanisms of fear dysregulation in PTSD, it is important to start with a valid animal model of the disorder. This protocol describes the methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of PTSD, in both rats and mice. SEFL was developed to recapitulate critical aspects of PTSD, including long-term sensitization of fear learning caused by an acute stressor. SEFL uses aspects of Pavlovian fear conditioning but produces a distinct and robust sensitized fear response far greater than normal conditional fear responses. The trauma procedure involves placing a rodent in a conditioning chamber and administering 15 unsignaled shocks randomly distributed over 90 minutes (for rat experiments; for mouse experiments, 10 unsignaled shocks randomly distributed over 60 minutes are used). On day 2, rodents are placed in a novel conditioning context where they receive a single shock; then, on day 3 they are placed back in the same context as on day 2 and tested for changes in freezing levels. Rodents that previously received the trauma display enhanced levels of freezing on the test day compared to those that received no shocks on the first day. Thus, with this model, a single highly stressful experience (the trauma) produces extreme fear of the stimuli associated with the traumatic event.

Here we describe the detailed methodology required to conduct stress-enhanced fear learning (SEFL) experiments, a preclinical model of post-traumatic stress disorder, in both rats and mice. The model utilizes aspects of Pavlovian fear conditioning and freezing as an index of enhanced fear in rodents.

压力增强恐惧学习--创伤后应激障碍的健壮啮齿动物模型

Fear behaviors are important for survival, but disproportionately high levels of fear can increase the vulnerability for developing psychiatric disorders ...

Fear Incubation Using an Extended Fear-Conditioning Protocol for Rats

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the relationships between aversive events and otherwise neutral stimuli. The most-widely utilized procedures for studying emotional memories entail fear conditioning in rats. In these tasks, the unconditioned stimulus (US) is a footshock presented once or several times across single or several sessions, and the conditioned response (CR) is freezing. In a version of these procedures, called cued fear conditioning, a tone (conditioned stimulus, CS) is paired with footshocks (US) during the training phase. During the first test, animals are exposed to the same context in which training took place, and freezing responses are tested in the absence of footshocks and tones (i.e., a context test). During the second test, freezing is measured when the context is changed (e.g., by manipulating the smell and walls of the experimental chamber) and the tone is presented in the absence of footshocks (i.e., a cue test). Most cued fear conditioning procedures entail few tone-shock pairings (e.g., 1-3 trials in a single session). There is a growing interest in less common versions involving an extensive number of pairings (i.e., overtraining) related to the long-lasting effect called fear incubation (i.e., fear responses increase over time without further exposure to aversive events or conditioned stimuli). Extended fear-conditioning tasks have been key to the understanding of fear incubation&#8217;s behavioral and neurobiological aspects, including its relationship with other psychological phenomena (e.g., post-traumatic stress disorder). Here, we describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.

We describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.

对大鼠使用扩展的恐惧调节协议进行恐惧孵化

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the ...

A Novel Pavlovian Fear Conditioning Paradigm to Study Freezing and Flight Behavior

Fear- and anxiety-related behaviors significantly contribute to an organism&#8217;s survival. However, exaggerated defensive responses to perceived threat are characteristic of various anxiety disorders, which are the most prevalent form of mental illness in the United States. Discovering the neurobiological mechanisms responsible for defensive behaviors will aid in the development of novel therapeutic interventions. Pavlovian fear conditioning is a widely used laboratory paradigm to study fear-related learning and memory. A major limitation of traditional Pavlovian fear conditioning paradigms is that freezing is the only defensive behavior monitored. We recently developed a modified Pavlovian fear conditioning paradigm that allows us to study both conditioned freezing and flight (also known as escape) behavior within individual subjects. This model employs higher intensity footshocks and a greater number of pairings between the conditioned stimulus and unconditioned stimulus. Additionally, this conditioned flight paradigm utilizes serial presentation of pure tone and white noise auditory stimuli as the conditioned stimulus. Following conditioning in this paradigm, mice exhibit freezing behavior in response to the tone stimulus, and flight responses during the white noise. This conditioning model can be applied to the study of rapid and flexible transitions between behavioral responses necessary for survival.

Defensive behavioral responses are contingent upon threat intensity, proximity, and context of exposure. Based on these factors, we developed a classical conditioning paradigm that elicits clear transitions between conditioned freezing and flight behavior within individual subjects. This model is crucial for the understanding the pathologies involved in anxiety, panic, and post-traumatic stress disorders.

研究冻结和飞行行为的新型帕夫洛夫恐惧调理范式

Fear- and anxiety-related behaviors significantly contribute to an organism&#8217;s survival. However, exaggerated defensive responses to perceived threat ...

An Inescapable Cat Odor Exposure Protocol for Studying Innate and Contextual Threat Conditioning in Rats

Animals respond to threatening situations by exhibiting a number of defensive behaviors, including avoidance, freezing, and risk assessment. An animal model with an ethological approach offers a deeper insight into the biological mechanisms underlying threat responses. This paper describes a methodology to measure defensive behaviors toward both innate and learned aversive stimuli in rats. Animals were individually exposed to predator odor in an inescapable chamber to elicit a measurable, sustained, defensive state. The experimental design involved placing a rat in a familiar chamber for 10 min followed by exposure to cat odor for another 10 min in the same context. The next day, the rats were re-exposed for 10 min to the same context chamber where cat odor exposure occurred. Sessions were video-recorded and defensive behaviors were assessed on both days. 
The behavioral test was coupled with reversible functional inactivation and c-Fos immunohistochemistry techniques to determine the role of the interoceptive cortex in threat responses. Rats exposed to cat odor on the first day and re-exposed to the context chamber on the second day displayed higher levels of defensive behaviors, and that cat odor elicited a robust increase in the neural activity of the interoceptive cortex. Moreover, muscimol inactivation of the interoceptive cortex reduced the expression of defensive behaviors in response to cat odor and impaired contextual threat memory. These results show that this behavioral assay is a useful tool for studying neural mechanisms of defensive behaviors and may offer insight into mechanisms that mediate fear in humans and its related disorders.

Cat skin/fur odor exposure provides a reliable method to investigate neural circuits and mechanisms of defensive responses in rodents and may offer insight into mechanisms that mediate fear in humans. Here, we describe a protocol for investigating the role of the interoceptive cortex in threat responses in rats.

Animals respond to threatening situations by exhibiting a number of defensive behaviors, including avoidance, freezing, and risk assessment. An animal ...