For decades, the mammalian hippocampus has been the focus of cellular, anatomical, behavioral, and computational studies aimed at understanding the fundamental mechanisms underlying cognition. Long recognized as the brain's seat for learning and memory, a wealth of knowledge has been accumulated on how the hippocampus processes sensory input, builds complex associations between objects, events, and space, and stores this information in the form of memories to be retrieved later in life. However, despite major efforts, our understanding of hippocampal cognitive function remains fragmentary, and models trying to explain it are continually revisited. Here, we review the literature across all above-mentioned domains and offer a new perspective by bringing attention to the most distinctive, and generally neglected, feature of the mammalian hippocampal formation, namely, the structural separability of the two blades of the dentate gyrus into “supra-pyramidal” and “infra-pyramidal”. Next, we discuss recent reports supporting differential effects of adult neurogenesis in the regulation of mature granule cell activity in these two blades. We propose a model for how differences in connectivity and adult neurogenesis in the two blades can potentially provide a substrate for subtly different cognitive functions.

中文翻译：

---

磨砺齿状回的刀片：成年神经元如何差异调节海马学习和记忆的各个方面

几十年来，哺乳动物的海马体一直是细胞、解剖、行为和计算研究的焦点，旨在了解认知的基本机制。长期以来，海马体被认为是大脑学习和记忆的所在地，关于海马体如何处理感官输入，如何在物体、事件和空间之间建立复杂的关联，以及如何以记忆的形式存储这些信息以供以后检索，已经积累了大量的知识。在生活中。然而，尽管付出了巨大的努力，我们对海马认知功能的理解仍然不完整，并且试图解释它的模型不断被重新审视。在这里，我们回顾了所有上述领域的文献，并通过关注哺乳动物海马结构最独特且通常被忽视的特征，即齿状回两个叶片的结构可分离性，提供了一个新的视角。 “锥体上”和“锥体下”。接下来，我们讨论最近的报告，这些报告支持成体神经发生对这两个叶片中成熟颗粒细胞活性的调节的不同影响。我们提出了一个模型，用于说明两个叶片中的连接性和成体神经发生的差异如何可能为细微不同的认知功能提供基础。