Gould R L, Arroyo B, Brown R G, Owen A M, Bullmore E T, Howard R J
MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, Section of Old Age Psychiatry, London, UK.
Neurology. 2006 Sep 26;67(6):1011-7. doi: 10.1212/01.wnl.0000237534.31734.1b.
To determine whether patients with Alzheimer disease (AD) compensate for neuropathologic changes when performing a mnemonic task by recruiting 1) the same brain regions as age-matched, healthy controls, but to a greater extent; 2) additional brain regions not activated by controls; or 3) both.
Twelve patients with mild probable AD and 12 healthy age- and education-matched controls participated in an fMRI study of successful encoding and retrieval of visuospatial paired associates. To ensure successful performance in both groups, participants were given multiple attempts to learn associations between two and three object locations.
The pattern of brain activity in patients with AD performing an easy version of the task was indistinguishable from that of controls performing a harder version of the task. Increased activation in left medial and right lateral prefrontal cortices was found in patients with AD compared to controls during encoding of two object locations, but not when this level of encoding in patients was compared with encoding of three object locations in controls.
There was no evidence of neural plasticity in the form of recruitment of novel brain regions in patients with Alzheimer disease. Data supported greater recruitment of the same brain regions as age-matched controls as a means of compensating for neuropathology and associated cognitive impairment in Alzheimer disease.
通过研究以下情况来确定阿尔茨海默病（AD）患者在执行记忆任务时是否会对神经病理学变化进行代偿：1）与年龄匹配的健康对照者激活相同的脑区，但程度更强；2）激活对照者未激活的额外脑区；或3）两者皆有。
12名轻度可能患有AD的患者以及12名年龄和教育程度相匹配的健康对照者参与了一项功能磁共振成像（fMRI）研究，该研究涉及视觉空间配对联想的成功编码和检索过程。为确保两组参与者都能成功完成任务，给予他们多次尝试来学习两个和三个物体位置之间的关联。
执行简易版任务时，AD患者的脑活动模式与执行更难版本任务的对照者无法区分。在对两个物体位置进行编码时，与对照者相比，AD患者左侧内侧和右侧外侧前额叶皮质的激活增加，但将患者的此编码水平与对照者对三个物体位置的编码进行比较时，情况并非如此。
没有证据表明阿尔茨海默病患者存在以募集新脑区形式出现的神经可塑性。数据支持AD患者更多地募集与年龄匹配的对照者相同脑区，以此作为代偿阿尔茨海默病神经病理学及相关认知障碍的一种方式。
