Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil; Ophidiarium LNN-FMRP-USP/INeC, Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), 14049-900, Brazil; NAP-USP-Neurobiology of Emotions Research Centre (NuPNE), Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto (SP), 14049-900, Brazil.
Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP 05508-000, Brazil.
Behav Brain Res. 2020 Mar 2;381:112469. doi: 10.1016/j.bbr.2020.112469. Epub 2020 Jan 7.
In the present study, we examined behavioral and brain regional activation changes of rats). To a nonmammalian predator, a wild rattler snake (Crotalus durissus terrificus). Accordingly, during snake threat, rat subjects showed a striking and highly significant behavioral response of freezing, stretch attend, and, especially, spatial avoidance of this threat. The brain regional activation patterns for these rats were in broad outline similar to those of rats encountering other predator threats, showing Fos activation of sites in the amygdala, hypothalamus, and periaqueductal gray matter. In the amygdala, only the lateral nucleus showed significant activation, although the medial nucleus, highly responsive to olfaction, also showed higher activation. Importantly, the hypothalamus, in particular, was somewhat different, with significant Fos increases in the anterior and central parts of the ventromedial hypothalamic nucleus (VMH), in contrast to patterns of enhanced Fos expression in the dorsomedial VMH to cat predators, and in the ventrolateral VMH to an attacking conspecific. In addition, the juxtodorsalmedial region of the lateral hypothalamus showed enhanced Fos activation, where inputs from the septo-hippocampal system may suggest the potential involvement of hippocampal boundary cells in the very strong spatial avoidance of the snake and the area it occupied. Notably, these two hypothalamic paths appear to merge into the dorsomedial part of the dorsal premammillary nucleus and dorsomedial and lateral parts of the periaqueductal gray, all of which present significant increases in Fos expression and are likely to be critical for the expression of defensive behaviors in responses to the snake threat.
在本研究中，我们检查了大鼠的行为和大脑区域激活变化。针对一种非哺乳动物捕食者，即野生响尾蛇（Crotalus durissus terrificus）。因此，在蛇类威胁时，大鼠表现出显著且高度显著的冻结、伸展注意力以及特别回避这种威胁的空间回避行为反应。这些大鼠的大脑区域激活模式大致类似于遇到其他捕食者威胁的大鼠，显示出杏仁核、下丘脑和导水管周围灰质中 Fos 的激活。在杏仁核中，只有外侧核显示出明显的激活，尽管对嗅觉高度敏感的内侧核也显示出更高的激活。重要的是，下丘脑略有不同，腹内侧下丘脑核（VMH）的前区和中区出现显著的 Fos 增加，与猫捕食者的 VMH 背侧和与攻击同种的 VMH 腹外侧的 Fos 表达增强模式形成对比。此外，外侧下丘脑的近背侧内侧区域显示出增强的 Fos 激活，来自隔海马系统的输入可能表明海马边界细胞可能参与对蛇及其占据区域的强烈空间回避。值得注意的是，这两条下丘脑路径似乎融合到背前乳突核的背侧部分和导水管周围灰质的背侧和外侧部分，所有这些都显示出 Fos 表达的显著增加，并且可能是对蛇威胁做出防御行为表达的关键。
