Abstract：
Although the hippocampus is one of the most-studied brain regions in mammals, research on the avian hippocampus has been more limited in scope. It is generally agreed that the hippocampus is an ancient feature of the amniote brain, and therefore homologous between the two lineages. Because birds and mammals are evolutionarily not very closely related, any shared anatomy is likely to be crucial for shared functions of their hippocampi. These functions, in turn, are likely to be essential if they have been conserved for over 300 million years. Therefore, research on the avian hippocampus can help us understand how this brain region evolved and how it has changed over evolutionary time. Further, there is a strong research foundation in birds on hippocampal-supported behaviors such as spatial navigation, food caching, and brood parasitism that scientists can build upon to better understand how hippocampal anatomy, network circuitry, endocrinology, and physiology can help control these behaviors. In this review, we summarize our current understanding of the avian hippocampus in spatial cognition as well as in regulating anxiety, approach-avoidance behavior, and stress responses. Although there are still some questions about the exact number of subdivisions in the avian hippocampus and how that might vary in different avian families, there is intriguing evidence that the avian hippocampus might have complementary functional profiles along the rostral-caudal axis similar to the dorsal-ventral axis of the rodent hippocampus, where the rostral/dorsal hippocampus is more involved in cognitive processes like spatial learning and the caudal/ventral hippocampus regulates emotional states, anxiety, and the stress response. Future research should focus on elucidating the cellular and molecular mechanisms - including endocrinological - in the avian hippocampus that underlie behaviors such as spatial navigation, spatial memory, and anxiety-related behaviors, and in so doing, resolve outstanding questions about avian hippocampal function and organization.
摘要：
尽管海马是哺乳动物研究最多的大脑区域之一，对鸟类海马体的研究范围有限。人们普遍认为海马是羊膜脑的古老特征，因此两个谱系之间是同源的。因为鸟类和哺乳动物在进化上并不密切相关，任何共享的解剖结构可能对海马体的共享功能至关重要。这些功能,反过来,如果它们已经保存了超过3亿年，它们可能是必不可少的。因此,对鸟类海马体的研究可以帮助我们了解这个大脑区域是如何进化的，以及随着进化时间的推移它是如何变化的。Further,鸟类在海马支持的行为方面有很强的研究基础，如空间导航，食物缓存，以及科学家们可以利用它们来更好地理解海马解剖结构，网络电路，内分泌学,和生理学可以帮助控制这些行为。在这次审查中,我们总结了我们目前对鸟类海马在空间认知以及调节焦虑方面的理解，趋避行为，和应激反应。尽管对于鸟类海马体的确切细分数量以及在不同的鸟类家族中可能存在的差异仍然存在一些问题，有有趣的证据表明，禽类海马可能具有沿着头尾轴的互补功能轮廓，类似于啮齿动物海马的背腹轴，其中头端/背侧海马更多参与认知过程，如空间学习和尾/腹侧海马调节情绪状态，焦虑,和应激反应。未来的研究应该集中在阐明鸟类海马中的细胞和分子机制-包括内分泌学-作为空间导航等行为的基础，空间记忆,和焦虑相关的行为，这样做，解决有关鸟类海马功能和组织的突出问题。
