Sexually divergent expression of active and passive conditioned fear responses in rats
Sexually divergent expression of active and passive conditioned fear responses in rats
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DOI：
10.7554/elife.11352
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发表时间：
2015-11-14
期刊：
影响因子：
7.7
通讯作者：
Shansky, Rebecca M.
中科院分区：
文献类型：
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作者：
Gruene, Tina M.;Flick, Katelyn;Shansky, Rebecca M.
巴甫洛夫恐惧条件反射的传统啮齿动物模型通过量化冻结反应来评估学习的强度。然而，对这一衡量标准的唯一依赖包括了一个事实上的假设，即任何运动活动都反映了恐惧的缺失。因此，联想学习的替代表达很少被考虑。在这里，我们发现了一种新颖的、活跃的恐惧反应（“飞奔”），主要发生在雌性大鼠身上。在女性中，飞奔表现出习得性恐惧行为的特征，随着条件反射的进行出现在CS期，而在消失过程中从CS期消失。这一发现激发了对啮齿动物恐惧条件反射研究的重新解释，特别是在雌性中，它表明条件反射恐惧行为比以前所认识的更加多样化。此外，在最初的恐惧条件反射中逃跑的大鼠在第二天的消失测试中表现出更低的冻结，这表明雌性采用独特的适应性恐惧反应策略来改善长期结果。
Traditional rodent models of Pavlovian fear conditioning assess the strength of learning by quantifying freezing responses. However, sole reliance on this measure includes the de facto assumption that any locomotor activity reflects an absence of fear. Consequently, alternative expressions of associative learning are rarely considered. Here we identify a novel, active fear response ('darting') that occurs primarily in female rats. In females, darting exhibits the characteristics of a learned fear behavior, appearing during the CS period as conditioning proceeds and disappearing from the CS period during extinction. This finding motivates a reinterpretation of rodent fear conditioning studies, particularly in females, and it suggests that conditioned fear behavior is more diverse than previously appreciated. Moreover, rats that darted during initial fear conditioning exhibited lower freezing during the second day of extinction testing, suggesting that females employ distinct and adaptive fear response strategies that improve long-term outcomes.