Laboratory of Emotions Neurobiology, BRAINCITY-Centre of Excellence for Neural Plasticity and Brain Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
Laboratory of Spatial Memory, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
Curr Biol. 2021 Jun 7;31(11):2347-2358.e6. doi: 10.1016/j.cub.2021.03.047. Epub 2021 Apr 12.
Animals display a rich repertoire of defensive responses adequate to the threat proximity. In social species, these reactions can be additionally influenced by the behavior of fearful conspecifics. However, the majority of neuroscientific studies on socially triggered defensive responses focuses on one type of behavior, freezing. To study a broader range of socially triggered reactions and underlying mechanisms, we directly compared two experimental paradigms, mimicking occurrence of the imminent versus remote threat. Observation of a partner currently experiencing aversive stimulation evokes passive defensive responses in the observer rats. Similar interaction with a partner that has just undergone the aversive stimulation prompts animals to increase active exploration. Although the observers display behaviors similar to those of the aversively stimulated demonstrators, their reactions are not synchronized in time, suggesting that observers' responses are caused by the change in their affective state rather than mimicry. Using opsins targeted to behaviorally activated neurons, we tagged central amygdala (CeA) cells implicated in observers' responses to either imminent or remote threat and reactivated them during the exploration of a novel environment. The manipulation revealed that the two populations of CeA cells promote passive or active defensive responses, respectively. Further experiments confirmed that the two populations of cells at least partially differ in expression of molecular markers (protein kinase C-δ [PKC-δ] and corticotropin-releasing factor [CRF]) and connectivity patterns (receiving input from the basolateral amygdala or from the anterior insula). The results are consistent with the literature on single subjects' fear conditioning, suggesting that similar neuronal circuits control defensive responses in social and non-social contexts.
动物表现出丰富的防御反应 repertoire，足以应对威胁 proximity。在社交物种中，这些反应还可以受到恐惧同类行为的影响。然而，大多数关于社交触发防御反应的神经科学研究都集中在一种行为上，即 freezing。为了研究更广泛的社交触发反应和潜在机制，我们直接比较了两种实验范式，模拟了即将发生的威胁和远程威胁的发生。观察到一个目前正在经历刺激的伴侣会在观察者老鼠中引起被动防御反应。与刚刚经历过刺激的伴侣进行类似的互动会促使动物增加主动探索。尽管观察者表现出与受刺激的示范者相似的行为，但它们的反应在时间上没有同步，这表明观察者的反应是由其情感状态的变化引起的，而不是模仿。使用靶向行为激活神经元的 opsin，我们标记了中央杏仁核（CeA）中与观察者对即将发生或远程威胁的反应有关的细胞，并在探索新环境时重新激活它们。操纵结果表明，CeA 中的这两种细胞群分别促进被动或主动防御反应。进一步的实验证实，这两种细胞群至少在分子标记物（蛋白激酶 C-δ [PKC-δ]和促肾上腺皮质素释放因子 [CRF]）和连接模式（接收来自外侧杏仁核或前岛叶的输入）方面存在部分差异。这些结果与关于单个受试者恐惧条件反射的文献一致，表明类似的神经元回路控制社交和非社交环境中的防御反应。
