The hippocampus plays a key role for episodic memory. In addition, a small but growing number of studies has shown that it also contributes to the resolution of response conflicts. It is less clear how these two functions are related, and how they are affected by hippocampal lesions in patients with mesial temporal lobe epilepsy (MTLE). Previous studies suggested that conflict stimuli might be better remembered, but whether the hippocampus is critical for supporting this interaction between conflict processing and memory formation is unknown. Here, we tested 19 patients with MTLE due to hippocampal sclerosis and 19 matched healthy controls. Participants performed a face-word Stroop task during functional magnetic resonance imaging (fMRI) followed by a recognition task for the faces. We tested whether memory performance and activity in brain regions implicated in long-term memory were modulated by conflict during encoding, and whether this differed between MTLE patients and controls. In controls, we largely replicated previous findings of improved memory for conflict stimuli. While MTLE patients showed response time slowing during conflict trials as well, they did not exhibit a memory benefit. In controls, neural activity of conflict resolution and memory encoding interacted within a hippocampal region of interest. Here, left hippocampal recruitment was less efficient for memory performance in incongruent trials than in congruent trials, suggesting an intrahippocampal competition for limited resources. They also showed an involvement of precuneus and posterior cingulate cortex during conflict resolution. Both effects were not observed in MTLE patients, where activation of the precuneus and posterior cingulate cortex instead predicted later memory. Further research is needed to find out whether our findings reflect widespread functional reorganization of the episodic memory network due to hippocampal dysfunction.

中文翻译：

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探讨海马体与冲突引起的记忆力改善的相关性

海马体在情景记忆中起着关键作用。此外，少量但越来越多的研究表明，它也有助于解决应对冲突。目前尚不清楚这两种功能如何相关，以及它们如何受到内侧颞叶癫痫 (MTLE) 患者海马病变的影响。先前的研究表明，冲突刺激可能更容易被记住，但海马体是否对支持冲突处理和记忆形成之间的这种相互作用至关重要尚不清楚。在这里，我们测试了 19 名因海马硬化而患有 MTLE 的患者和 19 名匹配的健康对照。参与者在功能磁共振成像 (fMRI) 期间执行面部词 Stroop 任务，然后是面部识别任务。我们测试了与长期记忆有关的大脑区域的记忆表现和活动是否受编码过程中的冲突调节，以及这在 MTLE 患者和对照组之间是否存在差异。在对照中，我们在很大程度上复制了先前关于改善冲突刺激记忆的发现。虽然 MTLE 患者在冲突试验中也表现出反应时间变慢，但他们并没有表现出记忆方面的益处。在对照中，冲突解决和记忆编码的神经活动在感兴趣的海马区域内相互作用。在这里，在不一致的试验中，左侧海马的募集对记忆表现的效率低于一致试验，这表明海马内对有限资源的竞争。他们还表现出在冲突解决过程中楔前叶和后扣带回皮层的参与。在 MTLE 患者中未观察到这两种效应，其中楔前叶和后扣带皮层的激活反而预测了以后的记忆。需要进一步的研究来确定我们的发现是否反映了由于海马功能障碍引起的情景记忆网络的广泛功能重组。