Fleisher Adam S, Podraza Katherine M, Bangen Katherine J, Taylor Curtis, Sherzai Ayesha, Sidhar Kunal, Liu Thomas T, Dale Anders M, Buxton Richard B
University of California at San Diego, Department of Neuroscience, La Jolla, CA 92037-0949, United States.
Neurobiol Aging. 2009 Nov;30(11):1737-48. doi: 10.1016/j.neurobiolaging.2008.01.012. Epub 2008 Mar 5.
Functional MRI has demonstrated differences in response to memory performance based on risk for Alzheimer's disease (AD). The current study compared blood oxygen level dependent (BOLD) functional MRI response with arterial spin labeling (ASL) perfusion response during an associative encoding task and resting perfusion signal in different risk groups for AD. Thirteen individuals with a positive family history of AD and at least one copy of the apolipoprotien E epsilon4 (APOE4) gene (high risk) were compared to ten individuals without these risk factors (low risk). In the medial temporal lobes (MTLs) the high risk group had an elevated level of resting perfusion, and demonstrated decreased fractional BOLD and perfusion responses to the encoding task. However, there was no difference in the absolute cerebral blood flow during the task. These data demonstrate that individuals with increased risk for Alzheimer's disease have elevated MTL resting cerebral blood flow, which significantly influences apparent differences in BOLD activations. BOLD activations should be interpreted with caution, and do not necessarily reflect differences in neuronal activation.
功能磁共振成像已证明，基于患阿尔茨海默病（AD）的风险，大脑对记忆表现的反应存在差异。本研究比较了不同AD风险组在联想编码任务期间的血氧水平依赖（BOLD）功能磁共振成像反应与动脉自旋标记（ASL）灌注反应，以及静息灌注信号。将13名有AD家族史且至少携带一份载脂蛋白Eε4（APOE4）基因拷贝的个体（高风险组）与10名无这些风险因素的个体（低风险组）进行了比较。在内侧颞叶（MTL），高风险组的静息灌注水平升高，并且对编码任务的BOLD分数反应和灌注反应降低。然而，任务期间的绝对脑血流量没有差异。这些数据表明，患阿尔茨海默病风险增加的个体MTL静息脑血流量升高，这显著影响了BOLD激活的明显差异。对BOLD激活的解释应谨慎，其不一定反映神经元激活的差异。
