The Weizmann Institute, Rehovot, Israel.
Hippocampus. 2010 Dec;20(12):1332-8. doi: 10.1002/hipo.20751.
Recent observations have caused a drastic shift in the conception of the hippocampus as a homogeneous structure that subserves cognitive functions, either spatial maps or short term episodic memory, to a structure that is associated with both cognitive and emotional functions. In fact, the assignment of cognitive functions to the hippocampus is restricted to its dorsal sector. In contrast, the ventral hippocampus (VH) appears to be associated with control of behavioral inhibition, stress and emotional memory, but not with strictly cognitive functions. Curiously, the VH but not the dorsal hippocampus (DH) is associated with the development of affective disorders. In line with these collective observations, we and others have found that the ability to evoke a sustained long term potentiation (LTP), a cellular correlate of learning and memory, is much lower in the VH compared to the DH. Strikingly, acute stress as well as direct exposure to corticosterone affect DH and VH in an opposite manner; causing facilitation of LTP in the VH and its suppression in the DH. This double dissociative action results from activation of different steroid receptor species in the DH and VH. Since the DH and VH differ in efferent connectivity, and since the strength of LTP can be considered as an indicator of strength of synaptic connectivity, these results suggest that stress regulates the routes by which the hippocampus is functionally linked to the rest of the brain such that under stress, the ventral route to the amygdala is enabled while the dorsal route to the neocortex is suppressed. This selective routing may underlie the complex outcome of stress on hippocampal and amygdala physiology and behavior.
最近的观察结果导致人们对海马体的概念发生了巨大转变，从一个单一的结构（负责空间地图或短期情景记忆等认知功能）转变为一个与认知和情感功能都相关的结构。事实上，将认知功能分配给海马体仅限于其背侧区域。相比之下，腹侧海马体（VH）似乎与行为抑制、应激和情绪记忆的控制有关，但与严格的认知功能无关。奇怪的是，只有 VH 而不是背侧海马体（DH）与情感障碍的发展有关。与这些观察结果一致，我们和其他人发现，与学习和记忆相关的细胞相关性——持续的长时程增强（LTP）的诱发能力在 VH 中比在 DH 中要低得多。引人注目的是，急性应激以及直接暴露于皮质酮以相反的方式影响 DH 和 VH；导致 VH 中的 LTP 易化和 DH 中的 LTP 抑制。这种双重分离作用是由 DH 和 VH 中不同的类固醇受体种类的激活引起的。由于 DH 和 VH 在传出连接上存在差异，并且 LTP 的强度可以被认为是突触连接强度的指标，因此这些结果表明，应激调节了海马体与大脑其他部分的功能连接方式，使得在应激下，通向杏仁核的腹侧通路被启用，而通向新皮层的背侧通路被抑制。这种选择性路由可能是应激对海马体和杏仁体生理学和行为的复杂影响的基础。
