Hippocampal activation in patients with mild cognitive impairment is necessary for successful memory encoding
Hippocampal activation in patients with mild cognitive impairment is necessary for successful memory encoding
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DOI：
10.1136/jnnp.2006.104877
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发表时间：
2007-08-01
影响因子：
11
通讯作者：
Leube, Dirk T.
中科院分区：
文献类型：
--
作者：
Kircher, Tilo T.;Weis, Susanne;Leube, Dirk T.
背景：情景记忆使我们能够有意识地回忆个人经历的过去事件。轻度认知障碍（MCI）患者的记忆表现会下降，轻度认知障碍是阿尔茨海默病（AD）的一种高危疾病。患者和方法：我们使用功能性MRI（fMRI）比较了29名健康老年受试者（平均年龄67.7（SD 5.4）岁）和21名轻度认知障碍（MCI）患者（平均年龄69.7（SD 7.0）岁）在记忆编码过程中的大脑活动。受试者记住了一系列的单词，而功能磁共振成像数据被收购。之后，他们必须从一系列干扰词中识别出这些词。事件相关范式的使用使得有可能选择性地分析每个个体中成功编码的项目。结果：MCI患者组与健康对照组在成功编码过程中，左侧海马和内侧颞叶（MTL）激活的差异主要表现在左侧海马和内侧颞叶周围区域。结论：MCI患者MTL激活的增加是成功记忆编码的必要条件。海马体的激活可能有助于将新学到的信息与已经存储在记忆中的项目联系起来。MCI中MTL区域的激活增加可能反映了对AD病理学开始的代偿反应。
Background: Episodic memory enables us to consciously recollect personally experienced past events. Memory performance is reduced in patients with mild cognitive impairment (MCI), an at-risk condition for Alzheimer's disease ( AD).Patients and methods: We used functional MRI ( fMRI) to compare brain activity during memory encoding in 29 healthy elderly subjects ( mean age 67.7 (SD 5.4) years) and 21 patients with MCI ( mean age 69.7 ( SD 7.0) years). Subjects remembered a list of words while fMRI data were acquired. Later, they had to recognise these words among a list of distractor words. The use of an event related paradigm made it possible to selectively analyse successfully encoded items in each individual. We compared activation for successfully encoded words between healthy elderly subjects and patients with MCI.Results: The main intergroup difference was found in the left hippocampus and surrounding medial temporal lobe (MTL) regions for the patients with MCI compared with healthy subjects during successful encoding.Conclusion: These results suggest that in patients with MCI, an increase in MTL activation is necessary for successful memory encoding. Hippocampal activation may help to link newly learned information to items already stored in memory. Increased activation in MTL regions in MCI may reflect a compensatory response to the beginning of AD pathology.