Universidad de Buenos Aires, Facultad de Medicina, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Buenos Aires, Argentina.
Laboratorio de Memoria y Cognición Molecular, Instituto de Neurociencia Cognitiva y Traslacional, CONICET-Fundación INECO-Universidad Favaloro, Buenos Aires, Argentina.
Neurobiol Learn Mem. 2021 Dec;186:107544. doi: 10.1016/j.nlm.2021.107544. Epub 2021 Oct 29.
Recognition memory can rely on three components: "what", "where" and "when". Recently we demonstrated that the anterior retrosplenial cortex (aRSC), like the perirhinal cortex (PRH) and unlike the hippocampus (HP), is required for consolidation of the "what" component. Here, we aimed at studying which brain structures interact with the aRSC to process object recognition (OR) memory in rats. We studied the interaction of six brain structures that are connected to the aRSC during OR memory processing: PRH, medial prefrontal cortex (mPFC), anteromedial thalamic nuclei (AM), medial entorhinal cortex (MEC), anterior cingulate cortex (ACC) and the dorsal HP (dHP). We previously described the role of the PRH and dHP, so we first studied the participation of the mPFC, AM, MEC and ACC in OR memory consolidation by bilateral microinfusions of the GABA receptor agonist muscimol. We observed an impairment in OR long-term memory (LTM) when inactivating the mPFC, the AM and the MEC, but not the ACC. Then, we studied the functional connections by unilateral inactivation of the aRSC and each one of the six structures in the same (ipsilateral) or the opposite (contralateral) hemisphere. Our results showed an amnesic LTM effect in rats with ipsilateral inactivations of aRSC-PRH, aRSC-mPFC, aRSC-AM, or aRSC-MEC. On the other hand, we observed memory impairment when aRSC-ACC were inactivated in opposite hemispheres, and no effect when the aRSC-dHP connection was inactivated. Thus, our ipsilateral inactivation findings reveal that the aRSC and, at least one brain region required in OR LTM processing are essential to consolidate OR memory. In conclusion, our results show that several cortico-cortical and cortico-thalamic pathways are important for OR memory consolidation.
“什么”“哪里”和“何时”。最近我们证明，前背侧隔核（aRSC）与边缘下皮层（PRH）一样，而与海马体（HP）不同，是“什么”成分巩固所必需的。在这里，我们旨在研究哪些大脑结构与 aRSC 相互作用，以在大鼠中处理物体识别（OR）记忆。我们研究了在 OR 记忆处理过程中与 aRSC 连接的六个大脑结构的相互作用：PRH、内侧前额叶皮层（mPFC）、前内侧丘脑核（AM）、内侧内嗅皮层（MEC）、前扣带皮层（ACC）和背侧 HP（dHP）。我们之前描述了 PRH 和 dHP 的作用，因此我们首先通过双侧微注射 GABA 受体激动剂 muscimol 研究了 mPFC、AM、MEC 和 ACC 在 OR 记忆巩固中的参与。我们观察到，当抑制 mPFC、AM 和 MEC 时，会损害 OR 长期记忆（LTM），但不会损害 ACC。然后，我们通过单侧失活 aRSC 以及同一（同侧）或相反（对侧）半球中的六个结构中的每一个来研究功能连接。我们的结果显示，在同侧失活 aRSC-PRH、aRSC-mPFC、aRSC-AM 或 aRSC-MEC 的大鼠中出现健忘性 LTM 效应。另一方面，当对侧失活 aRSC-ACC 时，我们观察到记忆损伤，而当失活 aRSC-dHP 连接时，没有观察到损伤。因此，我们的同侧失活发现表明，aRSC 和至少一个在 OR LTM 处理中需要的大脑区域对于巩固 OR 记忆是必不可少的。总之，我们的结果表明，几个皮质-皮质和皮质-丘脑通路对于 OR 记忆巩固很重要。
