Ventral hippocampus inactivation enhances the extinction of active avoidance responses in the presence of safety signals but leaves discrete trial operant active avoidance performance intact
Ventral hippocampus inactivation enhances the extinction of active avoidance responses in the presence of safety signals but leaves discrete trial operant active avoidance performance intact
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DOI：
10.1002/hipo.23202
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发表时间：
2020-03-04
期刊：
影响因子：
3.5
通讯作者：
Ito, Rutsuko
中科院分区：
文献类型：
--
作者：
Cavdaroglu, Bilgehan;Toy, Jeffrey;Ito, Rutsuko
主动回避(AA)行为的获得通常由两个信号的存在来辅助--预测厌恶事件(例如，电击)未来发生的警告信号和成功避免来袭电击时呈现的安全信号。虽然警告信号可以被认为是巴甫洛夫式的恐惧信号，很可能是由巴甫洛式恐惧信号条件作用下的大脑区域调节的，但安全信号背后的神经基础不太清楚，主要是因为AA任务没有明确的警告信号。本研究使用一种新的离散试验范式，试图研究腹侧海马区(VH)在无明确警告信号的情况下获得的安全信号AA表现中的作用。成年雄性Long Evans大鼠被分成两组，训练它们在有或没有安全信号的情况下获得AA反应。对采集和稳定状态性能数据的分析表明，仅有安全信号并不能改善AA响应的采集或性能。此外，训练后，可逆的VH失活并不影响稳态回避行为。然而，在接受安全信号训练的组中，回避反应的消退是容易的，这种影响被VH灭活进一步增强。额外的高架加迷宫(EPM)、明暗盒子和运动测试表明，VH灭活可以减少焦虑，而不影响运动能力。综上所述，这些结果表明，当安全信号发出时，VH在消除持续性病理性回避行为方面具有重要意义。
The acquisition of active avoidance (AA) behavior is typically aided by the presence of two signals-the warning signal, which predicts the future occurrence of an aversive event (e.g., shocks), and the safety signal, which is presented upon successful avoidance of oncoming shocks. While the warning signal could be conceived to act as a Pavlovian fear cue, and is likely mediated by brain areas that underlie Pavlovian fear cue conditioning, the neural substrates underlying safety signaling are less clear, largely due to the unavailability of AA tasks that are devoid of an explicit warning signal. The present study sought to investigate the role of the ventral hippocampus (VH) in safety signaled AA performance acquired without an explicit warning signal, using a novel discrete trial paradigm. Adult male Long Evans rats were divided into two groups and trained to acquire AA responses with, or without a safety signal. Analysis of the acquisition and stable state performance data revealed that the availability of a safety signal alone did not improve the acquisition or performance of AA responses. Furthermore, post-training, reversible VH inactivation did not impact stable state avoidance behavior. However, extinction of avoidance responses was facilitated in the group trained with a safety signal, and this effect was further potentiated by VH inactivation. Additional elevated plus maze (EPM), light-dark box, and locomotor tests demonstrated that VH inactivation reduced anxiety without affecting locomotor activity. Taken together, these results demonstrate the importance of VH in the extinction of persistent pathological avoidance behavior when safety is signaled.