Department of Psychology, University of California, Los Angeles, Los Angeles, California 90095.
Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, California 90095.
J Neurosci. 2021 Jun 23;41(25):5399-5420. doi: 10.1523/JNEUROSCI.2450-20.2021. Epub 2021 Apr 21.
The brainstem dorsal periaqueductal gray (dPAG) has been widely recognized as being a vital node orchestrating the responses to innate threats. Intriguingly, recent evidence also shows that the dPAG mediates defensive responses to fear conditioned contexts. However, it is unknown whether the dPAG displays independent or shared patterns of activation during exposure to innate and conditioned threats. It is also unclear how dPAG ensembles encode and predict diverse defensive behaviors. To address this question, we used miniaturized microscopes to obtain recordings of the same dPAG ensembles during exposure to a live predator and a fear conditioned context in male mice. dPAG ensembles encoded not only distance to threat, but also relevant features, such as predator speed and angular offset between mouse and threat. Furthermore, dPAG cells accurately encoded numerous defensive behaviors, including freezing, stretch-attend postures, and escape. Encoding of behaviors and of distance to threat occurred independently in dPAG cells. dPAG cells also displayed a shared representation to encode these behaviors and distance to threat across innate and conditioned threats. Last, we also show that escape could be predicted by dPAG activity several seconds in advance. Thus, dPAG activity dynamically tracks key kinematic and behavioral variables during exposure to threats, and exhibits similar patterns of activation during defensive behaviors elicited by innate or conditioned threats. These data indicate that a common pathway may be recruited by the dPAG during exposure to a wide variety of threat modalities. The dorsal periaqueductal gray (dPAG) is critical to generate defensive behaviors during encounters with threats of multiple modalities. Here we use longitudinal calcium transient recordings of dPAG ensembles in freely moving mice to show that this region uses shared patterns of activity to represent distance to an innate threat (a live predator) and a conditioned threat (a shock grid). We also show that dPAG neural activity can predict diverse defensive behaviors. These data indicate the dPAG uses conserved population-level activity patterns to encode and coordinate defensive behaviors during exposure to both innate and conditioned threats.
脑于背侧导水管周围灰质（dPAG）已被广泛认为是协调对先天威胁反应的关键节点。有趣的是，最近的证据也表明，dPAG 介导了对恐惧条件性情境的防御反应。然而，尚不清楚 dPAG 在暴露于先天和条件性威胁时是否表现出独立或共享的激活模式。也不清楚 dPAG 集合如何编码和预测不同的防御行为。为了解决这个问题，我们使用微型显微镜在雄性小鼠中获得了在暴露于活体捕食者和恐惧条件性情境期间相同的 dPAG 集合的记录。dPAG 集合不仅编码了与威胁的距离，还编码了相关特征，例如捕食者的速度和老鼠与威胁之间的角度偏移。此外，dPAG 细胞准确地编码了许多防御行为，包括冻结、伸展-关注姿势和逃避。dPAG 细胞中的行为和与威胁的距离编码是独立发生的。dPAG 细胞还显示出共同的表示形式，以在先天和条件性威胁中编码这些行为和与威胁的距离。最后，我们还表明，dPAG 活动可以在几秒钟前预测逃避。因此，dPAG 活动在暴露于威胁时动态跟踪关键运动学和行为变量，并在先天或条件性威胁引发的防御行为中表现出相似的激活模式。这些数据表明，在暴露于多种威胁模式时，dPAG 可能会募集到一条共同的通路。背侧导水管周围灰质（dPAG）在遇到多种模态的威胁时对于产生防御行为至关重要。在这里，我们使用自由移动小鼠的 dPAG 集合的纵向钙瞬变记录来表明，该区域使用共享的活动模式来表示与先天威胁（活体捕食者）和条件性威胁（电击网格）的距离。我们还表明，dPAG 神经活动可以预测多种防御行为。这些数据表明，dPAG 使用保守的群体水平活动模式来编码和协调暴露于先天和条件性威胁时的防御行为。
