School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.
School of Clinical Sciences, University of Bristol, Bristol, UK.
Nat Neurosci. 2017 Feb;20(2):242-250. doi: 10.1038/nn.4472. Epub 2017 Jan 9.
Episodic memory formation depends on information about a stimulus being integrated within a precise spatial and temporal context, a process dependent on the hippocampus and prefrontal cortex. Investigations of putative functional interactions between these regions are complicated by multiple direct and indirect hippocampal-prefrontal connections. Here application of a pharmacogenetic deactivation technique enabled us to investigate the mnemonic contributions of two direct hippocampal-medial prefrontal cortex (mPFC) pathways, one arising in the dorsal CA1 (dCA1) and the other in the intermediate CA1 (iCA1). While deactivation of either pathway impaired episodic memory, the resulting pattern of mnemonic deficits was different: deactivation of the dCA1→mPFC pathway selectively disrupted temporal order judgments while iCA1→mPFC pathway deactivation disrupted spatial memory. These findings reveal a previously unsuspected division of function among CA1 neurons that project directly to the mPFC. Such subnetworks may enable the distinctiveness of contextual information to be maintained in an episodic memory circuit.
情景记忆的形成依赖于将关于刺激的信息整合到精确的时空背景中，这个过程依赖于海马体和前额叶皮层。对这些区域之间假定的功能相互作用的研究由于海马体和前额叶皮层之间存在多种直接和间接的连接而变得复杂。在这里，应用一种遗传药理学失活技术使我们能够研究两条直接的海马体-内侧前额叶皮层（mPFC）通路的记忆贡献，一条源自背侧 CA1（dCA1），另一条源自中间 CA1（iCA1）。虽然两条通路中的任何一条失活都会损害情景记忆，但记忆缺陷的模式却不同：dCA1→mPFC 通路的失活选择性地破坏了时间顺序判断，而 iCA1→mPFC 通路的失活破坏了空间记忆。这些发现揭示了直接投射到 mPFC 的 CA1 神经元之间以前未被怀疑的功能分工。这样的子网可能使情景记忆回路中能够保持上下文信息的独特性。
