Oxford Project to Investigate Memory and Ageing, University of Oxford, United Kingdom.
Biol Psychiatry. 2013 Sep 1;74(5):375-83. doi: 10.1016/j.biopsych.2013.04.015. Epub 2013 May 28.
Functional magnetic resonance imaging (fMRI) has great potential for measuring mechanisms of functional changes in Alzheimer's disease (AD) and mild cognitive impairment, but task fMRI studies have produced conflicting results, partly due to failure to account for underlying morphological changes and to variations in patients' ability to perform the tasks. Resting fMRI has potential for assessing brain function independently from a task, but greater understanding of how networks of resting functional connectivity relate to the functioning of the brain is needed. We combined resting fMRI and task fMRI to examine the correspondence between these methods in individuals with cognitive impairment.
Eighty elderly (25 control subjects, 25 mild cognitive impairment, 30 AD) underwent a combined multimodal magnetic resonance imaging protocol including task fMRI and resting fMRI. Task fMRI data were acquired during the execution of a memory paradigm designed to account for differences in task performance. Structural and physiological confounds were modeled for both fMRI modalities.
Successful recognition was associated with increased task fMRI activation in lateral prefrontal regions in AD relative to control subjects; this overlapped with increased resting fMRI functional connectivity in the same regions.
Our results show that task fMRI and resting fMRI are sensitive markers of residual ability over the known changes in brain morphology and cognition occurring in AD and suggest that resting fMRI has a potential to measure the effect of new treatments.
功能磁共振成像（fMRI）在测量阿尔茨海默病（AD）和轻度认知障碍的功能变化机制方面具有很大的潜力，但任务 fMRI 研究产生了相互矛盾的结果，部分原因是未能考虑到潜在的形态变化以及患者执行任务的能力的变化。静息 fMRI 具有独立于任务评估大脑功能的潜力，但需要进一步了解静息功能连接网络与大脑功能的关系。我们结合静息 fMRI 和任务 fMRI，研究了认知障碍个体中这两种方法之间的对应关系。
80 名老年人（25 名对照组、25 名轻度认知障碍、30 名 AD）接受了包括任务 fMRI 和静息 fMRI 的联合多模态磁共振成像方案。任务 fMRI 数据是在执行旨在解释任务表现差异的记忆范式期间采集的。对两种 fMRI 模式都进行了结构和生理混杂因素的建模。
AD 患者的认知表现与侧前额叶区域的任务 fMRI 激活增加有关，而控制组则没有；这与同一区域的静息 fMRI 功能连接增加相重叠。
我们的结果表明，任务 fMRI 和静息 fMRI 是 AD 中已知的脑形态和认知变化中残留能力的敏感标志物，并表明静息 fMRI 有可能测量新治疗方法的效果。
