Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
Department of Psychology & Neuroscience Program, The University of the South, Sewanee, Tennessee.
Hippocampus. 2020 Jul;30(7):733-744. doi: 10.1002/hipo.23198. Epub 2020 Feb 20.
When faced with changing contingencies, animals can use memory to flexibly guide actions, engaging both frontal and temporal lobe brain structures. Damage to the hippocampus (HPC) impairs episodic memory, and damage to the prefrontal cortex (PFC) impairs cognitive flexibility, but the circuit mechanisms by which these areas support flexible memory processing remain unclear. The present study investigated these mechanisms by temporarily inactivating the medial PFC (mPFC), the dorsal HPC (dHPC), and the ventral HPC (vHPC), individually and in combination, as rats learned spatial discriminations and reversals in a plus maze. Bilateral inactivation of either the dHPC or vHPC profoundly impaired spatial learning and memory, whereas bilateral mPFC inactivation primarily impaired reversal versus discrimination learning. Inactivation of unilateral mPFC together with the contralateral dHPC or vHPC impaired spatial discrimination and reversal learning, whereas ipsilateral inactivation did not. Flexible spatial learning thus depends on both the dHPC and vHPC and their functional interactions with the mPFC.
当面临不断变化的环境时，动物可以利用记忆灵活地指导行动，涉及额叶和颞叶脑区结构。海马体（HPC）损伤会损害情景记忆，前额叶皮层（PFC）损伤会损害认知灵活性，但这些区域支持灵活记忆处理的回路机制仍不清楚。本研究通过在大鼠学习正字迷宫中的空间辨别和反转时，分别和联合暂时失活内侧前额叶皮层（mPFC）、背侧海马体（dHPC）和腹侧海马体（vHPC），来研究这些机制。双侧 dHPC 或 vHPC 的失活会严重损害空间学习和记忆，而双侧 mPFC 的失活主要损害反转学习相对于辨别学习。单侧 mPFC 的失活加上对侧 dHPC 或 vHPC 的失活会损害空间辨别和反转学习，而同侧失活则不会。因此，灵活的空间学习依赖于 dHPC 和 vHPC 及其与 mPFC 的功能相互作用。
