Isolating physiologic noise sources with independently determined spatial measures
Isolating physiologic noise sources with independently determined spatial measures
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DOI：
10.1016/j.neuroimage.2007.07.004
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发表时间：
2007-10-01
期刊：
影响因子：
5.7
通讯作者：
Lowe, Mark J.
中科院分区：
文献类型：
--
作者：
Beall, Erik B.;Lowe, Mark J.
为了正确解释fMRI数据中生理噪声的存在，有必要对脉搏和呼吸数据进行并行测量。在某些情况下，由于实验范例或缺乏可用的监测设备，这种平行测量是困难的或不可能的。我们提出了一个强大的方法来确定直接采样的脉冲和呼吸数据的主体从功能磁共振成像数据本身，利用独立确定的空间加权矩阵。它表明，时间独立分量分析可以可靠地分离的空间和时间模式的生理噪声通过相关性，如果并行测量。这样确定的空间模式可以应用于同一对象的单独扫描，以产生特定于该独立扫描的时间模式。该方法的鲁棒性导致在多个受试者上平均的标准脑空间中创建空间权重矩阵的更一般的方法，以便在不需要任何（进一步）并行测量的情况下获取生理信号。所得到的心脏和呼吸估计器可以以类似于直接采样的生理信号的方式有效地使用，例如，直接输入到回顾性校正方法，评估任务的心脏和呼吸影响等。为研究者提供了用于估计此处所述采集协议（以及开发的其他协议）的心脏和呼吸源的空间混合矩阵，并可通过电子邮件从相应作者处获得。(C)2007爱思唯尔公司All rights reserved.
To properly account for the presence of physiologic noise in fMRI data, parallel measurement of pulse and respiratory data is necessary. In some cases, this parallel measurement is difficult or impossible due to the experimental paradigm or lack of available monitoring equipment. We present a robust method for determining the direct-sampled pulse and respiratory data for a subject from the fMRI data itself, utilizing an independently determined spatial weighting matrix. It is shown that temporal independent component analysis can reliably separate the spatial and temporal patterns of physiologic noise through correlation if the parallel measurement is made. The spatial patterns thus determined can be applied to a separate scan of the same subject to produce the temporal pattern specific to this independent scan. The robustness of this method leads to the more general method of creating spatial weight matrices in standard brain space averaged over multiple subjects in order to acquire the physiologic signals without the necessity of any (further) parallel measurements. The resulting cardiac and respiratory estimators can effectively be used in a manner similar to that of a direct-sampled physiologic signal, e.g., direct input to retrospective correction methods, evaluation of cardiac and respiratory effects of tasks, etc. Spatial mixing matrices for estimating cardiac and respiratory sources for the acquisition protocols described here (and others as they are developed) are offered to investigators and can be obtained through e-mail from the corresponding author. (C) 2007 Elsevier Inc. All rights reserved.