An improved approach to detection of amplitude of low-frequency fluctuation (ALFF) for resting-state fMRI: Fractional ALFF
An improved approach to detection of amplitude of low-frequency fluctuation (ALFF) for resting-state fMRI: Fractional ALFF
复制标题
静息态 fMRI 低频波动幅度 (ALFF) 检测的改进方法：分数 ALFF
DOI：
10.1016/j.jneumeth.2008.04.012
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发表时间：
2008-07-15
影响因子：
3
通讯作者：
Zang, Yu-Feng
中科院分区：
文献类型：
--
作者：
Zou, Qi-Hong;Zhu, Chao-Zhe;Zang, Yu-Feng
大多数静息态功能磁共振成像（fMRI）研究从功能连接或功能整合的角度证明了空间上不同的脑区之间的相关性。功能连接方法不直接提供网络内每个脑区域的脑活动幅度的信息。或者，一个被称为静息态fMRI信号低频波动幅度（ALFF）的指标被建议用来反映局部自发脑活动的强度。然而，已经表明ALFF对生理噪声也很敏感。目前的研究提出了一种部分ALFF（fALFF）方法，即，低频（0.01-0.08 Hz）功率谱与整个频率范围功率谱的比值，并在两组静息态fMRI数据上进行了验证。结果表明，默认模式网络中的后扣带皮层、楔前叶、内侧前额叶皮层和双侧顶下小叶的fALFF显著高于其他脑区。这种模式与以前的神经影像学结果一致。静息态fMRI中脑池区的非特异性信号成分被显著抑制，表明fALFF方法提高了检测自发脑活动的敏感性和特异性。其机制及对异常脑活动的敏感性有待进一步研究。(C)2008 Elsevier B. V.保留所有权利。
Most of the resting-state functional magnetic resonance imaging (fMRI) studies demonstrated the correlations between spatially distinct brain areas from the perspective of functional connectivity or functional integration. The functional connectivity approaches do not directly provide information of the amplitude of brain activity of each brain region within a network. Alternatively, an index named amplitude of low-frequency fluctuation (ALFF) of the resting-state fMRI signal has been suggested to reflect the intensity of regional spontaneous brain activity. However, it has been indicated that the ALFF is also sensitive to the physiological noise. The current study proposed a fractional ALFF (fALFF) approach, i.e., the ratio of power spectrum of low-frequency (0.01-0.08 Hz) to that of the entire frequency range and this approach was tested in two groups of resting-state fMRI data. The results showed that the brain areas within the default mode network including posterior cingulate cortex, precuneus, medial prefrontal cortex and bilateral inferior parietal lobule had significantly higher fALFF than the other brain areas. This pattern was consistent with previous neuroimaging results. The non-specific signal components in the cistern areas in resting-state fMRI were significantly suppressed, indicating that the fALFF approach improved the sensitivity and specificity in detecting spontaneous brain activities. Its mechanism and sensitivity to abnormal brain activity should be evaluated in the future studies. (C) 2008 Elsevier B.V. All rights reserved.