Conditioned turning behavior: a Pavlovian fear response expressed during the post-encounter period following aversive stimulation.
Conditioned turning behavior: a Pavlovian fear response expressed during the post-encounter period following aversive stimulation.
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条件性转向行为：在厌恶刺激后的遭遇后时期表达的巴甫洛夫恐惧反应。
DOI：
10.1016/j.neuroscience.2010.06.046
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发表时间：
2010
期刊：
影响因子：
3.3
通讯作者：
Blair,HT
中科院分区：
文献类型：
--
作者：
Tarpley,JW;Shlifer,IG;Halladay,LR;Blair,HT
老鼠被训练成害怕听觉条件刺激（CS），方法是将其与轻微的电击（非条件刺激，US）配对，电击到一只眼皮上。训练后，CS引起了大鼠两种不同的条件恐惧反应：被动冻结反应和主动转身反应。这两种条件反应模式之间的平衡取决于大鼠最近与美国接触的历史。如果老鼠最近没有遇到美国，那么它们对CS的反应是冻结。但在最近遇到美国后，大鼠表现出了cs诱发的转向反应，这种反应总是指向远离训练过的眼睑，即使美国最近被传递到对面（未训练过的）眼睑。在未成对呈现CS和US的大鼠中没有观察到这种遭遇后的转身行为，这表明尽管CS诱发的转身在最近遭遇US后被选择性地表达出来，但它仍然是一种条件反射的巴甫洛夫恐惧反应，依赖于CS和US之间的习得关联。进一步支持这一结论的是，药理学失活实验表明，冻结和翻转行为的表达都依赖于杏仁核和导水管周围灰质（PAG）的侧化回路，而这些侧化回路已知支持巴甫洛夫恐惧反应的表达。这些发现表明，尽管CS引发巴甫洛夫恐惧反应的能力取决于CS - US配对的长期历史，但条件反应模式（在本实验中冻结与转向）可以被短期因素调节，例如最近的美国遭遇史。我们讨论了可能在不同防御反应模式之间介导这种短期转变的神经机制，并考虑了这种机制的失调如何可能导致临床焦虑症。
Rats were trained to fear an auditory conditioned stimulus (CS) by pairing it with a mild electric shock (the unconditioned stimulus, or US) delivered to one eyelid. After training, the CS elicited two different conditioned fear responses from rats: a passive freezing response, and an active turning response. The balance between these two modes of conditioned responding depended upon the rat's recent history of encounters with the US. If rats had not recently encountered the US, then they responded to the CS by freezing. But after recently encountering the US, rats exhibited CS-evoked turning responses that were always directed away from the trained eyelid, even if the US had recently been delivered to the opposite (untrained) eyelid. This post-encounter turning behavior was not observed in rats that had been trained with unpaired presentations of the CS and US, indicating that even though CS-evoked turning was selectively expressed after recent encounters with the US, it was nonetheless a conditioned Pavlovian fear response that depended upon a learned association between the CS and US. Further supporting this conclusion, pharmacological inactivation experiments showed that expression of both freezing and turning behaviors depended upon lateralized circuits in the amygdala and periaqueductal gray (PAG) that are known to support expression of Pavlovian fear responses. These findings indicate that even though the ability of a CS to elicit Pavlovian fear responses depend upon the long-term history of CS–US pairings, the mode of conditioned responding (freezing versus turning in the present experiments) can be modulated by short-term factors, such as the recent history of US encounters. We discuss neural mechanisms that might mediate such short-term transitions between different modes of defensive responding, and consider how dysregulation of such mechanisms might contribute to clinical anxiety disorders.