Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, Bordeaux, France.
Int J Neuropsychopharmacol. 2022 Jun 21;25(6):489-497. doi: 10.1093/ijnp/pyac012.
We previously showed that the infralimbic medial prefrontal cortex (IL-mPFC) plays an important role in recent and remote memory retrieval and extinction of conditioned odor aversion (COA) and contextual fear conditioning (CFC) in adult rats. Because the mPFC undergoes maturation during post-weaning, here, we aimed to explore (1) whether post-weanling rats can form recent and remote COA and CFC memory, and (2) the role of the IL-mPFC in mediating these processes.
To investigate the retrieval process, we transiently inactivated the IL-mPFC with lidocaine prior to the retrieval test at either recent or remote time points. To target the consolidation process, we applied the protein synthesis inhibitor after the retrieval at recent or remote time points.
Our results show that the post-weanling animals were able to develop both recent and remote memory of both COA and CFC. IL-mPFC manipulations had no effect on retrieval or extinction of recent and remote COA memory, suggesting that the IL has no effect in COA at this developmental stage. In contrast, the IL-mPFC played a role in (1) the extinction of recent, but not remote, CFC memory, and (2) the retrieval of remote, but not recent, CFC memory. Moreover, remote, but not recent, CFC retrieval enhanced c-Fos protein expression in the IL-mPFC.
Altogether, these results point to a differential role of the IL-mPFC in recent and remote CFC memory retrieval and extinction and further confirm the differences in the role of IL-mPFC in these processes in post-weanling and adult animals.
我们之前的研究表明，在成年大鼠中，扣带回前皮质（IL-mPFC）的下边缘区域在条件性厌恶（COA）和情境恐惧条件反射（CFC）的近期和远期记忆检索以及消退中起着重要作用。由于 mPFC 在断奶后会继续发育，因此，我们旨在探索（1）幼年期大鼠是否可以形成近期和远期 COA 和 CFC 记忆，以及（2）IL-mPFC 在介导这些过程中的作用。
为了研究检索过程，我们在近期或远期检索测试前，用利多卡因短暂地使 IL-mPFC 失活。为了靶向巩固过程，我们在近期或远期检索后应用蛋白合成抑制剂。
我们的结果表明，幼年期大鼠能够形成近期和远期 COA 和 CFC 的记忆。IL-mPFC 的操作对近期和远期 COA 记忆的检索或消退没有影响，这表明在这个发育阶段，IL 对 COA 没有影响。相反，IL-mPFC 在（1）近期 CFC 记忆的消退中发挥作用，但在远期 CFC 记忆的消退中不起作用，以及（2）远期 CFC 记忆的检索中发挥作用，但在近期 CFC 记忆的检索中不起作用。此外，远期但不是近期的 CFC 检索增强了 IL-mPFC 中的 c-Fos 蛋白表达。
总之，这些结果表明，IL-mPFC 在近期和远期 CFC 记忆检索和消退中的作用不同，并进一步证实了 IL-mPFC 在幼年期和成年动物中在这些过程中的作用存在差异。
