Méndez-Couz M, Conejo N M, González-Pardo H, Arias J L
Laboratory of Neuroscience, Department of Psychology. Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n, 33003 Oviedo, Spain.
Brain Res. 2015 Apr 24;1605:59-69. doi: 10.1016/j.brainres.2015.02.005. Epub 2015 Feb 11.
The standard model of memory system consolidation supports the temporal reorganization of brain circuits underlying long-term memory storage, including interactions between the dorsal hippocampus and extra-hippocampal structures. In addition, several brain regions have been suggested to be involved in the retrieval of spatial memory. In particular, several authors reported a possible role of the ventral portion of the hippocampus together with the thalamus or the striatum in the persistence of this type of memory. Accordingly, the present study aimed to evaluate the contribution of different cortical and subcortical brain regions, and neural networks involved in spatial memory retrieval. For this purpose, we used cytochrome c oxidase quantitative histochemistry as a reliable method to measure brain oxidative metabolism. Animals were trained in a hidden platform task and tested for memory retention immediately after the last training session; one week after completing the task, they were also tested in a memory retrieval probe. Results showed that retrieval of the previously learned task was associated with increased levels of oxidative metabolism in the prefrontal cortex, the dorsal and ventral striatum, the anterodorsal thalamic nucleus and the dentate gyrus of the dorsal and ventral hippocampus. The analysis of functional interactions between brain regions suggest that the dorsal and ventral dentate gyrus could be involved in spatial memory retrieval. In addition, the results highlight the key role of the extended hippocampal system, thalamus and striatum in this process. Our study agrees with previous ones reporting interactions between the dorsal hippocampus and the prefrontal cortex during spatial memory retrieval. Furthermore, novel activation patterns of brain networks involving the aforementioned regions were found. These functional brain networks could underlie spatial memory retrieval evaluated in the Morris water maze task.
记忆系统巩固的标准模型支持长期记忆存储背后脑回路的时间重组，包括背侧海马体与海马体外结构之间的相互作用。此外，有研究表明几个脑区参与空间记忆的提取。特别是，几位作者报告了海马体腹侧部分与丘脑或纹状体在这类记忆的持续存在中可能发挥的作用。因此，本研究旨在评估不同皮质和皮质下脑区以及参与空间记忆提取的神经网络的作用。为此，我们使用细胞色素c氧化酶定量组织化学作为一种可靠的方法来测量脑氧化代谢。动物接受隐藏平台任务训练，并在最后一次训练后立即测试记忆保持情况；完成任务一周后，它们还接受了记忆提取探针测试。结果表明，之前学习任务的提取与前额叶皮质、背侧和腹侧纹状体、丘脑前背核以及背侧和腹侧海马体的齿状回中氧化代谢水平的升高有关。脑区之间功能相互作用的分析表明，背侧和腹侧齿状回可能参与空间记忆提取。此外，结果突出了扩展海马系统、丘脑和纹状体在这一过程中的关键作用。我们的研究与之前报道空间记忆提取过程中背侧海马体与前额叶皮质之间相互作用的研究一致。此外，还发现了涉及上述区域的脑网络的新激活模式。这些功能性脑网络可能是在莫里斯水迷宫任务中评估的空间记忆提取的基础。
