School of Psychology, Cardiff University, Wales, UK.
Eur J Neurosci. 2024 May;59(10):2715-2731. doi: 10.1111/ejn.16303. Epub 2024 Mar 17.
In a changing environment, animals must process spatial signals in a flexible manner. The rat hippocampal formation projects directly upon the retrosplenial cortex, with most inputs arising from the dorsal subiculum and terminating in the granular retrosplenial cortex (area 29). The present study examined whether these same projections are required for spatial working memory and what happens when available spatial cues are altered. Consequently, injections of iDREADDs were made into the dorsal subiculum of rats. In a separate control group, GFP-expressing adeno-associated virus was injected into the dorsal subiculum. Both groups received intracerebral infusions within the retrosplenial cortex of clozapine, which in the iDREADDs rats should selectively disrupt the subiculum to retrosplenial projections. When tested on reinforced T-maze alternation, disruption of the subiculum to retrosplenial projections had no evident effect on the performance of those alternation trials when all spatial-cue types remained present and unchanged. However, the same iDREADDs manipulation impaired performance on all three alternation conditions when there was a conflict or selective removal of spatial cues. These findings reveal how the direct projections from the dorsal subiculum to the retrosplenial cortex support the flexible integration of different spatial cue types, helping the animal to adopt the spatial strategy that best meets current environmental demands.
在不断变化的环境中，动物必须以灵活的方式处理空间信号。大鼠海马结构直接投射到后隔核皮质，大多数输入来自背侧下托，并终止于颗粒状后隔核皮质（区域 29）。本研究探讨了这些相同的投射是否对空间工作记忆是必需的，以及当可用的空间线索发生变化时会发生什么。因此，将 iDREADDs 注射到大鼠背侧下托中。在一个单独的对照组中，将表达 GFP 的腺相关病毒注射到背侧下托中。两组均在前隔核皮质内接受氯氮平的脑内输注，在 iDREADDs 大鼠中，氯氮平应选择性地破坏下托到后隔核的投射。当在强化 T 型迷宫交替任务上进行测试时，当所有空间线索类型保持存在且不变时，破坏下托到后隔核的投射对那些交替试验的表现没有明显影响。然而，当存在冲突或选择性去除空间线索时，相同的 iDREADDs 操作会损害所有三种交替条件的表现。这些发现揭示了来自背侧下托到后隔核皮质的直接投射如何支持不同空间线索类型的灵活整合，帮助动物采用最能满足当前环境需求的空间策略。
