The appropriate selection of passive and active defensive behaviors in threatening situations is essential for survival. Previous studies have shown that passive defensive responses depend on activity of the central nucleus of the amygdala (CeA), whereas active ones primarily rely on the nucleus accumbens (NAc). However, the mechanisms underlying flexible switching between these two types of responses remain unknown. Here we show in mice that the paraventricular thalamus (PVT) mediates the selection of defensive behaviors through its interaction with the CeA and the NAc. We show that the PVT–CeA pathway drives conditioned freezing responses, whereas the PVT–NAc pathway is inhibited during freezing and, instead, signals active avoidance events. Optogenetic manipulations revealed that activity in the PVT–CeA or PVT–NAc pathway biases behavior toward the selection of passive or active defensive responses, respectively. These findings provide evidence that the PVT mediates flexible switching between opposing defensive behaviors.

The appropriate selection of passive and active defensive behaviors in threatening situations is essential for survival. 先前的研究表明，被动防御反应取决于杏仁核中央核 (CeA) 的活动，而主动防御反应主要依赖于伏隔核 (NAc)。然而，这两种响应之间灵活切换的机制仍然未知。在这里，我们在小鼠中表明，室旁丘脑 (PVT) 通过其与 CeA 和 NAc 的相互作用介导防御行为的选择。我们表明 PVT-CeA 通路驱动条件性冷冻反应，而 PVT-NAc 通路在冷冻过程中受到抑制，而是发出主动回避事件的信号。光遗传学操作表明，PVT-CeA 或 PVT-NAc 通路中的活动分别使行为偏向于选择被动或主动防御反应。这些发现提供了证据表明 PVT 介导了相反的防御行为之间的灵活转换。