Behavioral characteristics of rats predisposed to learned helplessness: Reduced reward sensitivity, increased novelty seeking, and persistent fear memories
Behavioral characteristics of rats predisposed to learned helplessness: Reduced reward sensitivity, increased novelty seeking, and persistent fear memories
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DOI：
10.1016/j.bbr.2005.06.016
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发表时间：
2005-11-07
影响因子：
2.7
通讯作者：
Gonzalez-Lima, F
中科院分区：
文献类型：
--
作者：
Shumake, J;Barrett, D;Gonzalez-Lima, F
先天无助的大鼠品系，这是有选择地增加易感性的习得性无助，可能模型的易感性情感障碍，包括抑郁症和创伤后应激障碍。除了选定的性状外，该菌株的行为没有得到很好的表征。在这项研究中，我们评估了先天无助大鼠的几个行为测试。首先，我们通过测量他们对5%蔗糖溶液的消耗来评估奖励敏感性。接下来，我们在一个新的和熟悉的开放领域，并在光暗测试中评估探索行为和恐惧。最后，我们通过在第一天（获得）将动物暴露于4个音调-电击对，然后在接下来的2天（消失）呈现60个音调来评估恐惧条件反射。与正常的Sprague-Dawley对照组相比，先天无助的大鼠在小说中表现出较少的蔗糖溶液消耗和更多的探索行为，但不是熟悉的开放领域。他们在明-暗测试中也表现出较少的恐惧，但更多的条件性冻结的语气预测休克。此外，这种冻结是抵抗灭绝的;先天无助的老鼠不仅没有表现出恐惧减少在灭绝，！但实际上表现出了恐惧的增加，这种现象被称为“矛盾增强”。“因此，先天无助的大鼠似乎具有一种行为表型，其特征是对奖励的敏感性降低，探索新环境的动力增加，形成和保持恐惧相关记忆的倾向增加。这种行为表型被认为与易受创伤后应激障碍影响的人的性格相似。(c)2005 Elsevier B. V.保留所有权利。
The congenitally helpless rat strain, which was selectively bred for increased susceptibility to learned helplessness, may model the predisposition to affective disorders, including depression and post-traumatic stress disorder. Other than the selected trait, the behavior of this strain is not well characterized. In this study, we assessed congenitally helpless rats on several behavioral tests. First, we assessed reward sensitivity by measuring their consumption of a 5% sucrose solution. Next, we assessed exploratory behavior and fearfulness in both a novel and familiar open field, and in a light-dark test. Finally, we assessed fear conditioning by exposing the animals to 4 tone-shock pairs on I day (acquisition) and then presenting 60 tones over the next 2 days (extinction). Compared to normal Sprague-Dawley controls, congenitally helpless rats showed less consumption of the sucrose solution and more exploratory behavior in the novel, but not the familiar, open fields. They also showed less fearfulness in the light-dark test, but more conditioned freezing to the tone predicting shock. Moreover, this freezing was resistant to extinction; congenitally helpless rats not only failed to show a fear decrement during extinction,!, but actually showed increased fear, a phenomenon termed "paradoxical enhancement." Thus, congenitally helpless rats appear to have a behavioral phenotype characterized by reduced sensitivity to reward, increased drive to explore novel environments, and increased propensity to form, and maintain fear-associated memories. This behavioral phenotype is discussed as resembling the personality of humans vulnerable to post-traumatic stress disorder. (c) 2005 Elsevier B.V. All rights reserved.