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.

中文翻译：

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面对蛇的大鼠的防御行为和脑区域激活变化。

在本研究中，我们检查了大鼠的行为和大脑区域激活变化。对于非哺乳动物的捕食者，是一条野生的响尾蛇蛇（Crotalus durissus terrificus）。因此，在蛇威胁期间，大鼠受试者表现出惊人的，非常显着的行为反应，包括冰冻，伸展运动，尤其是在空间上避免这种威胁。这些大鼠的大脑区域激活模式与遇到其他捕食者威胁的大鼠的大脑区域激活模式大致相似，显示杏仁核，下丘脑和导水管灰质部位的Fos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，尤其是下丘脑有些不同，Fos在腹内侧下丘脑核（VMH）的前部和中部显着增加，与猫的掠食者在背体VMH和攻击性同种的腹侧VMH中Fos表达增强的模式相反。此外，下丘脑外侧的并道内侧区域显示出增强的Fos激活，其中来自隔垫-海马系统的输入可能暗示海马边界细胞可能在非常强烈的避开蛇及其占据的区域中起作用。值得注意的是，这两个下丘脑路径似乎合并到了哺乳期前背核的背突部分以及导水管灰色的背突和外侧部分，