Dickerson B C, Salat D H, Greve D N, Chua E F, Rand-Giovannetti E, Rentz D M, Bertram L, Mullin K, Tanzi R E, Blacker D, Albert M S, Sperling R A
Department of Neurology, The Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Neurology. 2005 Aug 9;65(3):404-11. doi: 10.1212/01.wnl.0000171450.97464.49.
To use fMRI to investigate whether hippocampal and entorhinal activation during learning is altered in the earliest phase of mild cognitive impairment (MCI).
Three groups of older individuals were studied: 10 cognitively intact controls, 9 individuals at the mild end of the spectrum of MCI, and 10 patients with probable Alzheimer disease (AD). Subjects performed a face-name associative encoding task during fMRI scanning, and were tested for recognition of stimuli afterward. Data were analyzed using a functional-anatomic method in which medial temporal lobe (MTL) regions of interest were identified from each individual's structural MRI, and fMRI activation was quantified within each region.
Significantly greater hippocampal activation was present in the MCI group compared to controls; there were no differences between these two groups in hippocampal or entorhinal volumes. In contrast, the AD group showed hippocampal and entorhinal hypoactivation and atrophy in comparison to controls. The subjects with MCI performed similarly to controls on the fMRI recognition memory task; patients with AD exhibited poorer performance. Across all 29 subjects, greater mean entorhinal activation was found in the subgroup of 13 carriers of the APOE epsilon4 allele than in the 16 noncarriers.
The authors hypothesize that there is a phase of increased medial temporal lobe activation early in the course of prodromal Alzheimer disease followed by a subsequent decrease as the disease progresses.
使用功能磁共振成像（fMRI）研究在轻度认知障碍（MCI）的最早阶段，学习过程中海马体和内嗅皮层的激活是否发生改变。
对三组老年人进行了研究：10名认知功能正常的对照组、9名处于MCI谱系轻度阶段的个体以及10名可能患有阿尔茨海默病（AD）的患者。受试者在fMRI扫描期间执行面孔-名字联想编码任务，之后进行刺激识别测试。使用功能解剖学方法分析数据，其中从每个个体的结构磁共振成像（MRI）中识别出内侧颞叶（MTL）感兴趣区域，并在每个区域内对fMRI激活进行量化。
与对照组相比，MCI组的海马体激活明显更强；这两组在海马体或内嗅皮层体积上没有差异。相比之下，AD组与对照组相比表现出海马体和内嗅皮层激活不足以及萎缩。MCI受试者在fMRI识别记忆任务中的表现与对照组相似；AD患者表现较差。在所有29名受试者中，与16名非携带者相比，13名APOE ε4等位基因携带者亚组的平均内嗅皮层激活更强。
作者推测，在阿尔茨海默病前驱期病程早期存在内侧颞叶激活增加的阶段，随后随着疾病进展而下降。
