Department of Computational Synaptic Physiology, University of Göttingen, Göttingen, Germany.
Department of Neurosurgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Hippocampus. 2023 Jun;33(6):759-768. doi: 10.1002/hipo.23521. Epub 2023 Mar 20.
The hippocampus is a key structure involved in learning and remembering spatial information. However, the extent to which hippocampal region CA2 is involved in these processes remains unclear. Here, we show that chronically silencing dorsal CA2 impairs reversal learning in the Morris water maze. After platform relocation, CA2-silenced mice spent more time in the vicinity of the old platform location and less time in the new target quadrant. Accordingly, behavioral strategy analysis revealed increased perseverance in navigating to the old location during the first day and an increased use of non-spatial strategies during the second day of reversal learning. Confirming previous indirect indications, these results demonstrate that CA2 is recruited when mice must flexibly adapt their behavior as task contingencies change. We discuss how these findings can be explained by recent theories of CA2 function and outline testable predictions to understand the underlying neural mechanisms. Demonstrating a direct involvement of CA2 in spatial learning, this work lends further support to the notion that CA2 plays a fundamental role in hippocampal information processing.
海马体是参与学习和记忆空间信息的关键结构。然而，海马体 CA2 区在这些过程中所起的作用尚不清楚。在这里，我们发现慢性沉默背侧 CA2 会损害 Morris 水迷宫中的反转学习。在平台重新定位后，CA2 沉默的小鼠在旧平台位置附近花费的时间更多，在新目标象限花费的时间更少。因此，行为策略分析显示，在反转学习的第一天，它们在导航到旧位置时更坚持，在第二天，它们更倾向于使用非空间策略。这些结果证实了之前的间接迹象，表明当任务条件发生变化时，CA2 被招募以灵活地调整行为，从而证明了 CA2 的作用。我们讨论了如何用最近的 CA2 功能理论来解释这些发现，并概述了可检验的预测，以了解潜在的神经机制。本研究证明 CA2 直接参与空间学习，进一步支持了 CA2 在海马体信息处理中起着基础性作用的观点。
