Mohammed R. Milad is supported by NIMH grant R01 MH097880 and institutional funds from the Department of Psychiatry at MGH.

注:在本协议中的所有程序已经批准了小组委员会研究动物护理，作为该机构动物护理和使用委员会（IACUC）在马萨诸塞州总医院，并符合卫生准则的国家机构。 1.动物住房和处理程序<ol><li>抵达后，房屋成年SD雌性大鼠约8-10周龄（体重200-225克），在3-4英寸的塑料箱用木片床上用品组。维持它们在饮食中随意获得食物和水，并在12小时的光/暗周期。离开老鼠适应的住房条件和动物设施至少1周。 注:本稿件所有过程都是在光周期中进行。 </li><li>在此之后的适应期，处理所有动物的每个2-3天5分钟。正确地拿起大鼠一次一个（由躯干，而不是由尾支持），追究他们的安全，并在此期间抚摸。处理出现更多的强调，神经质，或焦虑的时间较长的动物。这样做是为了尽量减少处理压力，这可能会影响本协议的下列步骤。 注:天数和时间处理的动物可以在不同的实验室之间变化量;然而，这些都应该是相同的实验室内的实验之间保持一致。 </li></ol> 2.监测发情周期:阴道拭子拖尾和染色过程<ol><li>使0.9％盐溶液（溶解在蒸馏水氯化钠）。滋润在此溶液中的棉签。印迹使用纸巾，以避免过饱和，这可能导致样品收集或细胞的损失不足的小费。抱着尾巴向​​上远离阴道口，轻轻插入棉花尖端插入阴道运河和打滚的墙壁捕捉宽松阴道细胞。 </li><li>如果动物小便的婴儿床吨尖，更换一个新的，因为尿液污染将难以相鉴别。要格外小心，因为在此过程中不造成困扰的动物，因为接触应力破坏发情周期。当抽汲，旨在实现一个快速的插拔，是不是太深，以减少额外的刺激子宫颈，可引起假孕。 注:假孕可确定为无环发情周期通常持续约12天， 即发情间期25个连续天。 </li><li>小心地取出敷贴尖端和滚动它到一个预先标记的显微镜载玻片。避免按下太难为幻灯片上过多的液体可以相鉴别困难，一旦干燥。 注:一张幻灯片可以包含多个天的每只动物，尽管这可以根据个人的喜好来完成。 </li><li>确保样品转移到幻灯片。采集样品SEVER在一个人的滑动连续两天，以便能够更好地跟踪和识别每日发情期的变化。 注:如果可能的话，它也是理想的，如果人们采集样品保持相同的所有动物。 </li><li>一旦幻灯片是干的，开始染色协议相鉴别。使用染色试剂盒（见表材料），浸泡载玻片10倍，在固定液（浅蓝色），在染色溶液的10倍（粉红色）和5倍于染液溶液（紫色）。冲洗轻轻滑动，在流水下。让幻灯片完全风干显微镜下观察之前。 注:一般4-5天的长发情周期包括（按顺序）:发情期（E），发情后期（M），动情（D），和发情前期（P）26。发情的特点是蓝色，角化细胞，动情后期由白细胞和角化和有核细胞的组合，间情期是相似于细胞类型的存在，以动情后期除了它们是非常稀疏，动情前期由紫染色的聚集体的有核细胞（ 图1）。有各种染色方法，除了上述的那些，这是同样有效的用于阴道涂片细胞学检查。 </li><li>为了监测准确前实验阶段收集的样品在至少两个完整的周期（〜8-10天）。是同一天的样品所用的时间是一致的。每日贯穿并直到实验结束收集阴道涂片样品。 </li></ol> 3.预曝光<ol><li>在实验前的启动，将动物预暴露于调节腔室允许动物适应环境之前的任何行为测试的上下文中（调理室）。 <ol><li>预暴露的女性的调理室（位于声音衰减框）与房子灯每天20-30分钟3天之前的任何实验。它们是预先暴露于作为其腔室为研究分配的框。彻底清洁T字会话和动物之间他盒（墙壁和托盘），以去除异味，因为他们可以影响人的行为和发情周期。 </li></ol></li></ol> 4.第1天:习惯化/恐惧条件<ol><li>一旦动物已被证明是在其发情周期的发情期，开始为期3天的实验的习惯化/调理相。 <ol><li>取预音在实验中的每一天冷冻前到第一音调条件刺激（CS）的演示的基线测量。通过收购冻结百分之几十的CS发病前第一CS-单独开庭审理时的刺激，缺席的时间间隔内（由试验的持续时间，再乘以100花不动秒来计算的）做到这一点。 注意:可以用这些措施来评估，并与习惯，空调，灭绝和召回过程中比较基准冻结水平。 </li><li>要在发情后期阶段进行消退训练，调理老鼠发情期的最后一天。拭子并确定动情期（步骤2）的每一天开始的实验方案（调节/消光/调用）之前。由于发情期可能会持续更长的时间超过一天，使用周期的历史来预测阶段的长度来确定当动物准备开始训练。 </li></ol></li><li>在调理室中，对足部电击格栅地板连接到电刺激发生器。使用0.5-0.6 mA的刺激电平作为条件刺激（US）。使用4 kHz的80 dB音调作为条件刺激（CS）。 注意:这些参数可能跨越实验室变化，并且可以被修改为最佳调节。 <ol><li>如果冷冻分析程序需要视觉线索（相对于时间），共激活的LED光与色调。定位在光上的操作性室的外部，所述视频帧内的。在每次试验的开始，启动LED灯，并保持照明，直到日结束Ë审判。 注意:此光不被动物可见和仅作为一个标记为起始和所记录的视频文件内的试验结束（将用于测量冷冻行为）。 </li></ol></li><li>把动物进入空调室的习惯5 CS单机试验。紧随其后的习惯，应执行恐惧条件的7成对CS-美国选拔赛。确保CS音调持续30秒和coterminates与0.5秒美国休克。运行试验中的所有会话（习惯，调节，消光，并召回）具有可变intertrial间隔平均3分钟。 </li><li>在调理会议结束，返回动物到其家笼中，并给动物设施，直到第二天。 </li></ol> 5.第2天:准备雌二醇<ol><li>拭子并确定发情阶段所有接受该协议的第1天动物。制备雌二醇（也称为E2，17β-雌二醇，或β-雌二醇）用于15微克/千克的剂量皮下注射使用芝麻油或0.9％盐水作为溶媒。 </li><li>为了计算雌二醇的量为注射准备，使用所有的动物，这是测量和记录，当他们被空调有关此协议的第1天的体重。 </li><li>进行计算，以规范每鼠雌二醇（ 即 0.2ml）中的管理音量。因为雌二醇难以溶解，由于其不溶于水，并且需要大量的溶剂为小剂量时，通过混合雌二醇在芝麻油过热直至溶解制成原液。该溶液然后可以通过0.22微米过滤器以除去杂质。例如，为了实现15微克/千克的剂量在每只动物0.2注射体积添加的3000微克雌二醇/1毫升芝麻油原液芝麻油总所需体积计算的容积。 注:另外，用其他形式的雌激素的塔<html>吨是水溶性的和更容易溶解。 </li></ol> 6.第2天:雌二醇管理/消退训练<ol><li>管理雌二醇皮下。抬起肩胛骨之间的皮肤松弛的脖子形成平缓的捏和将注射器针头插入一个由皮肤折叠形成的三角形。 </li><li>下面雌二醇皮下注射30分钟后，再次将动物的调理室，并开始消退训练。在这种灭绝会议，进行20 CS单机试验，每个试验包括一个30秒，4千赫，80分贝色调，以可变intertrial间隔平均为3分钟介绍。 注:雌二醇对召回的影响时，雌二醇之​​前灭绝培训或灭绝后立即给予发生。效果没有观察4小时后的消光，因此建议注入在时间上接近的训练会话15的开头或结尾。 </li></ol>。乐"&gt; 7天3:灭绝召回<ol><li>灭绝训练后24小时，棉签上的天完成1和2本协议的动物。 </li><li>将动物进入分配给他们的空调室（同日1和2）。通过提供3 CS单机试验（灭绝召回三次试验），其中只包含3.80分贝与intertrial间隔类似给药灭绝培训20次试验CS单机试验按步骤6.2中所述开始灭绝召回会话。 </li><li>在召回会话完成后，返回的动物，以他​​们家的笼子。 </li></ol> 8.数据分析<ol><li>通过视频采集行为数据，并使用计算机软件对其进行分析。 注:冻结的分数也可以通过实验者是盲目的药物治疗的CS表示每次试验过程中定时冻结发作手工计算，表现为时间的百分比花的基调期间冻结。结冰由完全缺乏运动与在30秒CS-美国选拔赛异常呼吸定义。由花30秒（试验持续时间）乘以100冻结（动）秒除以计算百分比冻结。 </li></ol>

<ol>
	<li>Baron-Cohen, S., Knickmeyer, R. C., Belmonte, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+differences+in+the+brain:+implications+for+explaining+autism.">Sex differences in the brain: implications for explaining autism.</a> Science. 310 (5749), 819-823 (2005).</li><li>Voyer, D., Voyer, S., Bryden, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnitude+of+sex+differences+in+spatial+abilities:+a+meta-analysis+and+consideration+of+critical+variables.">Magnitude of sex differences in spatial abilities: a meta-analysis and consideration of critical variables.</a> Psychological Bulletin. 117 (2), 250-270 (1995).</li><li>Pinker, S., Spelke, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Conversation+with+Steven+Pinker+and+Elizabeth+Spelke.">A Conversation with Steven Pinker and Elizabeth Spelke.</a> The Science of Gender and Science. , (2005).</li><li>Hampson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen-related+variations+in+human+spatial+and+articulatory-motor+skills.">Estrogen-related variations in human spatial and articulatory-motor skills.</a> Psychoneuroendocrinology. 15, 97-111 (1990).</li><li>Hampson, E., Kimura, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reciprocal+effects+of+hormonal+fluctuations+on+human+motor+and+perceptual-spatial+skills.">Reciprocal effects of hormonal fluctuations on human motor and perceptual-spatial skills.</a> Behavioral Neuroscience. 102, 456-459 (1988).</li><li>Hampson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variations+in+sex-related+cognitive+abilities+across+the+menstrual+cycle.">Variations in sex-related cognitive abilities across the menstrual cycle.</a> Brain and Cognition. 14 (1), 26-43 (1990).</li><li>Kilpatrick, D. G., Resnick, H. S., Milanak, M. E., Miller, M. W., Keyes, K. M., Friedman, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=National+estimates+of+exposure+to+traumatic+events+and+PTSD+prevalence+using+DSM-IV+and+DSM-5+criteria.">National estimates of exposure to traumatic events and PTSD prevalence using DSM-IV and DSM-5 criteria.</a> Journal of Traumatic Stress. 26 (5), 537-547 (2013).</li><li>Breslau, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gender+differences+in+trauma+and+posttraumatic+stress+disorder.">Gender differences in trauma and posttraumatic stress disorder.</a> Journal of Gender-Specific Medicine. 5 (1), 34-40 (2002).</li><li>Frans, O., Rimmo, P. A., Aberg, L., Fredrikson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trauma+exposure+and+post-traumatic+stress+disorder+in+the+general+population.">Trauma exposure and post-traumatic stress disorder in the general population.</a> Acta Psychiatrica Scandinavica. 111 (4), 291-299 (2005).</li><li>Breslau, N., Kessler, R. C., Chilcoat, H. D., Schultz, L. R., Davis, G. C., Andreski, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trauma+and+posttraumatic+stress+disorder+in+the+community:+the+1996+Detroit+Area+Survey+of+Trauma.">Trauma and posttraumatic stress disorder in the community: the 1996 Detroit Area Survey of Trauma.</a> Archives of General Psychiatry. 55 (7), 626-632 (1996).</li><li>Seedat, S., Stein, D. J., Carey, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Post-traumatic+stress+disorder+in+women:+epidemiological+and+treatment+issues.">Post-traumatic stress disorder in women: epidemiological and treatment issues.</a> CNS Drugs. 19 (5), 411-427 (2005).</li><li>Holbrook, T. L., Hoyt, D. B., Stein, M. B., Sieber, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gender+differences+in+long-term+posttraumatic+stress+disorder+outcomes+after+major+trauma:+women+are+at+higher+risk+of+adverse+outcomes+than+men.">Gender differences in long-term posttraumatic stress disorder outcomes after major trauma: women are at higher risk of adverse outcomes than men.</a> Journal of Trauma. 53 (5), 882-888 (2002).</li><li>Labad, J., Menchon, J. M., Alonso, P., Segalas, C., Jimenez, S., Jaurrieta, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gender+differences+in+obsessive-compulsive+symptom+dimensions.">Gender differences in obsessive-compulsive symptom dimensions.</a> Depression and Anxiety. 25 (10), 832-838 (2008).</li><li>Gupta, R. R., Sen, S., Diepenhorst, L. L., Rudick, C. N., Maren, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+modulates+sexually+dimorphic+contextual+fear+conditioning+and+hippocampal+long-term+potentiation+(LTP)+in+rats.">Estrogen modulates sexually dimorphic contextual fear conditioning and hippocampal long-term potentiation (LTP) in rats.</a> Brain Research. 888, 356-365 (2001).</li><li>Milad, M. R., Igoe, S. A., Lebron-Milad, K., Novales, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrous+cycle+phase+and+gonadal+hormones+influence+conditioned+fear+extinction.">Estrous cycle phase and gonadal hormones influence conditioned fear extinction.</a> Neuroscience. 164 (3), 887-895 (2009).</li><li>Zeidan, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estradiol+modulates+medial+prefrontal+cortex+and+amygdala+activity+during+fear+extinction+in+women+and+female+rats.">Estradiol modulates medial prefrontal cortex and amygdala activity during fear extinction in women and female rats.</a> Biological Psychiatry. 70 (10), 920-927 (2011).</li><li>Lebron-Milad, K., Milad, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+differences,+gonadal+hormones+and+the+fear+extinction+network:+implications+for+anxiety+disorders.">Sex differences, gonadal hormones and the fear extinction network: implications for anxiety disorders.</a> Biology of Mood &amp; Anxiety Disorders. 2 (3), (2012).</li><li>Rey, C. D., Lipps, J., Shansky, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+d1+receptor+activation+rescues+extinction+impairments+in+low-estrogen+female+rats+and+induces+cortical+layer-specific+activation+changes+in+prefrontal-amygdala+circuits.">Dopamine d1 receptor activation rescues extinction impairments in low-estrogen female rats and induces cortical layer-specific activation changes in prefrontal-amygdala circuits.</a> Neuropsychopharmacology. 39 (5), 1282-1289 (2013).</li><li>Str&#246;m, J. O., Theodorsson, A., Ingberg, E., Isaksson, I. M., Theodorsson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovariectomy+and+17&#946;-estradiol+Replacement+in+Rats+and+Mice:+A+Visual+Demonstration.">Ovariectomy and 17&#946;-estradiol Replacement in Rats and Mice: A Visual Demonstration.</a> Journal of Visualized Experiments. , e4013 (2012).</li><li>Markham, J. A., Pych, J. C., Juraska, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovarian+hormone+replacement+to+aged+ovariectomized+female+rats+benefits+acquisition+of+the+morris+water+maze.">Ovarian hormone replacement to aged ovariectomized female rats benefits acquisition of the morris water maze.</a> Hormones &amp; Behavior. 42 (3), 284-293 (2002).</li><li>Markowska, A. L., Savonenko, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+estrogen+replacement+in+restoration+of+cognitive+function+after+long-term+estrogen+withdrawal+in+aging+rats.">Effectiveness of estrogen replacement in restoration of cognitive function after long-term estrogen withdrawal in aging rats.</a> Journal of Neuroscience. 22 (24), 10985-10995 (2002).</li><li>Bredemann, T. M., McMahon, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=17&#946;+Estradiol+Increases+Resilience+and+Improves+Hippocampal+Synaptic+Function+in+Helpless+Ovariectomized+Rats.">17&#946; Estradiol Increases Resilience and Improves Hippocampal Synaptic Function in Helpless Ovariectomized Rats.</a> Psychoneuroendocrinology. 42, 77-88 (2014).</li><li>Grueso, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early,+but+not+late+onset+estrogen+replacement+therapy+prevents+oxidative+stress+and+metabolic+alterations+caused+by+ovariectomy.">Early, but not late onset estrogen replacement therapy prevents oxidative stress and metabolic alterations caused by ovariectomy.</a> Antioxidants and Redox Signaling. 20 (2), 236-246 (2014).</li><li>Shughrue, P. J., Bushnell, C. D., Dorsa, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+receptor+messenger+ribonucleic+acid+in+female+rat+brain+during+the+estrous+cycle:+a+comparison+with+ovariectomized+females+and+intact+males.">Estrogen receptor messenger ribonucleic acid in female rat brain during the estrous cycle: a comparison with ovariectomized females and intact males.</a> Endocrinology. 131 (1), 381-388 (1992).</li><li>Frye, C. A., Erskine, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+time+of+mating+and+paced+copulation+on+induction+of+pseudopregnancy+in+cyclic+female+rats.">Influence of time of mating and paced copulation on induction of pseudopregnancy in cyclic female rats.</a> Journal of Reproduction and Fertility. 90 (2), 375-385 (1990).</li><li>Becker, J. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+and+methods+for+research+on+sex+differences+in+brain+and+behavior.">Strategies and methods for research on sex differences in brain and behavior.</a> Endocrinology. 146, 1650-1673 (2005).</li><li>Westwood, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+female+rat+reproductive+cycle:+a+practical+histological+guide+to+staging.">The female rat reproductive cycle: a practical histological guide to staging.</a> Toxicologic Pathology. 36 (3), 375-384 (2008).</li><li>Hurn, P. D., Macrae, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+as+a+Neuroprotectant+in+Stroke.">Estrogen as a Neuroprotectant in Stroke.</a> Journal of Cerebral Blood Flow &amp; Metabolism. 20, 631-652 (2000).</li><li>Parasuraman, S., Raveendran, R., Kesavan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+sample+collection+in+small+laboratory+animals.">Blood sample collection in small laboratory animals.</a> Journal of Pharmacology and Pharmacotherapeutics. 1 (2), 87-93 (2010).</li><li>Gillies, G. E., McArthur, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+actions+in+the+brain+and+the+basis+for+differential+action+in+men+and+women:+a+case+for+sex-specific+medicines.">Estrogen actions in the brain and the basis for differential action in men and women: a case for sex-specific medicines.</a> Pharmacological Reviews. 62 (2), 155-198 (2010).</li><li>Tolin, D. F., Foa, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+differences+in+trauma+and+posttraumatic+stress+disorder:+a+quantitative+review+of+25+years+of+research.">Sex differences in trauma and posttraumatic stress disorder: a quantitative review of 25 years of research.</a> Psychological Bulletin. 132, 959-992 (2006).</li></ol>

这个手稿的作者有没有竞争经济利益或其他利益冲突的披露。

恐惧灭绝已被广泛研究在雄性大鼠调处下各种操作识别和评估条件性恐惧灭绝的神经机制。相对而言，很少有研究探讨雌性大鼠或性腺激素的恐惧消退的作用。具体研究雌激素对恐惧消退的影响，自然循环雌性大鼠受到了为期三天的行为范式。这个过程包括习惯/调理，灭绝，灭绝和召回阶段。使用此协议，它已经证明，雌性大鼠低雌激素发情后期阶段表现出较高的冻结（或受损灭绝召回）相比，...

固有的性别差异在人类和啮齿类动物在不同的认知行为和学习的范式观察。例如，据报道，妇女一般有较强的口头和注重细节的能力，而男性有更好的空间能力1-3。这些性别差异可能是部分原因是由于性腺激素的影响。高雌激素水平提高，妇女更好的工作性能，但恶化的任务，男人通常做的很好4-6性能。虽然这方面的证据是引人注目的，有限的能力，以在人类研究中完全控制实验环境使得它以确定是否对行为这些效果可以特异性归因于激素难。动物研究，与此相反，允许完全控制的情况。 虽然恐惧消退的基本神经机制已经确定，并很好的研究，男性，目前还不清楚是否这些系统是在女性或他们如何在整个发情周期变化一样。恐惧空调和灭绝被广泛应用于行为范式在啮齿动物和人类进行相关的焦虑症的研究。鉴于妇女对焦虑症的风险较高，以及较高的症状的持续时间和严重程度7-13，这是至关重要的，包括女性在这些研究中。女性在这项研究中代表性不足可能是由于发情期的监测和会计的性激素的行为影响的挑战。实验室是做检查的女性中，往往没有报告或方法的研究，没有说明这方面遇到的问题。 新出现的证据在啮齿类动物表明，在恐惧中灭绝的性别差异是由性腺激素14-18调制。在恐惧条件，动物训练害怕一个特定的刺激。一些无筋介绍后的刺激下，动物学会不害怕线索，一个叫灭绝的过程。如何做好动物学习和巩固学习这个任务可以给灭绝训练一段时间后的消光回忆测试过程中应遵循的记忆。期间灭绝召回少恐惧的表情显示出良好的消记忆的巩固。从我们实验室最近的研究结果表明，雌激素能调节恐惧消退记忆的巩固和提高灭绝召回。具体来说，雌性大鼠被扑灭在发情前期，发情周期的阶段期间，循环雌激素水平的高峰，显示出增强记忆灭绝保留。与此相反，雌被熄灭在低雌动情后期阶段显示相对差的消光召回，它可以与外源性雌二醇给药之前或消退训练15,16后，立即得到改善。灭绝记忆巩固的神经机制（包括UDING性腺激素在女性中的作用）不清晰。 在动物实验中，激素的作用，可通过微创手术切除的程序，如阉割去势，并进行调查。随后，从手术后恢复，性腺激素往往外生一种行为的任务19的性能在操纵。这种方法提供了关于性激素关键信息和，因为它允许对性腺激素的良好控制的操作（在定时和剂量计）20-23是有用的。这种方法，然而，没有评估在整个发情周期发生也不它们代表"正常"的动物，从而限制了平移潜在对人的研究的天然存在的波动的影响。它已被充分证明了雌性激素水平峰值和下降的发情周期的特定阶段，和在循环内的雌激素受体的表达的变化，和卵巢切除后24。因此，有必要进行研究，女性用完整性腺和缩小的实验设计，以可靠地研究了高和低雌激素状态可能对女性在其整个生命周期的影响。 该协议的重点是雌激素对参与恐惧消退的神经生物学系统的作用。它描述了如何:1）认真监测发情周期，2）准备有效剂量雌激素的全身用药，和3）遵循的行为模式，包括恐惧空调，灭绝，并记得在自然循环雌性大鼠。此协议可与其它药理学和操纵细胞和分子的工具进行修改，以帮助研究，以更好地理解，在条件性恐惧观察消光特性的性别差异。注意，以下描述的过程是那些我们实验室内使用，且存在许多的这些过程的变化i的n中的文献。

<table><tbody><tr><td>Fear conditioning chamber</td><td>Coulbourn Instruments</td><td></td><td></td></tr><tr><td>Graphic State</td><td>Coulbourn Instruments</td><td></td><td></td></tr><tr><td>Sound-attenuating box</td><td>Med Associates, Inc.</td><td>NIR-022MD</td><td></td></tr><tr><td>Estradiol</td><td>Sigma-Aldrich</td><td>E1024</td><td>In sesame oil for subcutaneous injection</td></tr><tr><td>Sesame oil</td><td>Sigma-Aldrich</td><td>S3547-250ML</td><td></td></tr><tr><td>Freezescan</td><td>Cleversys, Inc.</td><td></td><td></td></tr><tr><td>Dip quick stain</td><td>Jorgensen Laboratories, Inc.</td><td>J0322A1, J0322A2, J0322A3</td><td></td></tr><tr><td>Cotton-tipped applicators</td><td>Fisher Scientific</td><td>23-400-114</td><td>6-inch, sterile</td></tr><tr><td>0.9% saline</td><td>LabChem, Inc.</td><td>LC23460-2</td><td>Sodium chloride w/v</td></tr><tr><td>Selectfrost microscope slides</td><td>Fisher Scientific</td><td>12-550-003</td><td></td></tr><tr><td>Virex II 256</td><td>Diversey, Inc.</td><td>5019317</td><td>Dilute 1:256 with water</td></tr><tr><td>Luer-Lok Tip 1ml Syringes</td><td>Becton Dickinson</td><td>309628</td><td></td></tr><tr><td>Hypodermic disposable needles</td><td>Exelint International, Co.</td><td>26402</td><td>26-gauge</td></tr></tbody></table>

protocol for studying extinction of conditioned fear in naturally cycling female rats

的条件性恐惧灭绝已被广泛研究在雄性啮齿动物。最近，已经有越来越多的研究表明，对某些行为的任务和应对行为的神经机制是在女性和男性不同。在调查研究使用雌性可以表示由于性腺激素在其动情周期的变化的一个挑战。本协议描述既定程序，在调查中雌性大鼠恐惧消退记忆的巩固雌激素的作用是有用的。发情周期和外源性雌激素的管理之前灭绝培训阶段可以在24小时后影响灭绝召回。这里描述的发情相鉴别阴道擦拭技术辅助检查和处理的自然循环性腺激素。使用这个基本啮齿动物模型可进一步划定由雌激素能调节中灭绝的恐惧记忆的机制女性。

在这种恐惧灭绝召回的协议，冻结百分比是衡量恐惧的指标。动物熄灭很好，保留了灭绝培训的内存表现出较低的恐惧在行为测试期间灭绝召回的最后一天。雄性和雌性大鼠不显著在条件性恐惧表达的调节，消光期间不同，并且召回相（ 图2）。然而，性别差异变得明显，当动物如高和低雌激素发情期组分别进行了分析。 ，在发情周期的低雌激素发情后期阶段进行消退训练雌鼠不记?...

Watch this Scientific Journal Video about Protocol for Studying Extinction of Conditioned Fear in Naturally Cycling Female Rats at JoVE.com

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

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 ...

protocol-for-studying-extinction-conditioned-fear-naturally-cycling

Research

JoVE Journal

Behavior

13.3K 次观看.  Massachusetts General Hospital. 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.

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

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

A Procedure for Studying the Footshock-Induced Reinstatement of Cocaine Seeking in Laboratory Rats

The most insidious aspect of drug addiction is the high propensity for relapse. Animal models of relapse, known as reinstatement procedures, have been used extensively to study the neurobiology and phenomenology of relapse to drug use. Although procedural variations have emerged over the past several decades, the most conventional reinstatement procedures are based on the drug self-administration (SA) model. In this model, an animal is trained to perform an operant response to obtain drug. Subsequently, the behavior is extinguished by withholding response-contingent reinforcement. Reinstatement of drug seeking is then triggered by a discrete event, such as an injection of the training drug, re-exposure to drug-associated cues, or exposure to a stressor 1.
Reinstatement procedures were originally developed to study the ability of acute non-contingent exposure to the training drug to reinstate drug seeking in rats and monkeys 1, 2. Reinstatement procedures have since been modified to study the role of environmental stimuli, including drug-associated cues and exposure to various forms of stress, in relapse to drug seeking 1, 3, 4.
Over the past 15 years, a major focus of the reinstatement literature has been on the role of stress in drug relapse. One of the most commonly used forms of stress for studying this relationship is acute exposures to mild, intermittent, electric footshocks. The ability of footshock stress to induce reinstatement of drug seeking was originally demonstrated by Shaham and colleagues (1995) in rats with a history of intravenous heroin SA5. Subsequently, the effect was generalized to rats with histories of intravenous cocaine, methamphetamine, and nicotine SA, as well as oral ethanol SA 3, 6.
Although footshock-induced reinstatement of drug seeking can be achieved reliably and robustly, it is an effect that tends to be sensitive to certain parametrical variables. These include the arrangement of extinction and reinstatement test sessions, the intensity and duration of footshock stress, and the presence of drug-associated cues during extinction and testing for reinstatement. Here we present a protocol for footshock-induced reinstatement of cocaine seeking that we have used with consistent success to study the relationship between stress and cocaine seeking.

Animal models of relapse, known as reinstatement procedures, have been used extensively to study the role of stress in relapse to drug seeking. Here, we report on a method for inducing the reinstatement of cocaine seeking in laboratory rats via acute exposures to mild, intermittent electric footshock.

在实验室老鼠研究求可卡因电击诱导恢复原状的程序

The most insidious aspect of drug addiction is the high propensity for relapse.  Animal models of relapse, known as reinstatement procedures, have been ...

神经科学

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 ...

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 ...

研究具有改良恐惧条件反射的小鼠的主动防御行为

Modified Fear Conditioning for Inducing Flight Behaviors in Mice

The appropriate manifestation of defensive behavior in a threatening situation is critical for survival. The prevailing theory suggests that an active defensive behavior, such as jumping or rapid darting, is expressed under high threat imminence or actual threat, whereas passive defensive behavior, such as freezing, is expressed when the threat is predicted, but the threat imminence is relatively low. In classical fear conditioning, subjects typically exhibit freezing as a conditioned defensive response, with little expression of active defensive behavior in most cases. Here, we introduce a modified fear conditioning procedure for mice to observe the transition from freezing to flight and vice versa, involving five repetitive pairings of conditioned stimuli (CS; continuous tone, 8 kHz, 95 dB SPL (sound pressure levels)) and unconditioned stimuli (US; foot shock, 0.9 mA, 1.0 s) over two days. This modified fear conditioning procedure requires a relatively large number of conditioning sessions and conditioning days but does not necessitate a high-intensity foot shock for modest expression of flight behavior. Using the same context for conditioning and salient CS presentations is essential to elicit flight behaviors. This modified fear conditioning procedure is a reliable method for observing active defensive behaviors in mice, providing an opportunity to elucidate the fine mechanisms and characteristics of such behaviors in a fearful context.

作者聚焦：探索恐惧学习和灭绝中防御行为的神经相关性

To study flight behaviors in a fearful context, we introduce a modified fear conditioning protocol. This protocol ensures that mice consistently exhibit flight behaviors during cue presentation in the fear conditioning.

改良的恐惧条件反射诱导小鼠的飞行行为

The appropriate manifestation of defensive behavior in a threatening situation is critical for survival. The prevailing theory suggests that an active ...