Task-related oxygenation and cerebral blood volume changes estimated from NIRS signals in motor and cognitive tasks
Task-related oxygenation and cerebral blood volume changes estimated from NIRS signals in motor and cognitive tasks
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DOI：
10.1016/j.neuroimage.2014.02.036
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发表时间：
2014-07
期刊：
影响因子：
5.7
通讯作者：
Hirokazu Tanaka;T. Katura;Hiroki Sato
中科院分区：
文献类型：
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作者：
Hirokazu Tanaka;T. Katura;Hiroki Sato
虽然功能近红外光谱（fNIRS）具有同时测量氧合血红蛋白和脱氧血红蛋白浓度（Δ[HbO]和Δ[HbR]）变化的优势，但只有少数分析方法利用了这一优势。作为我们最近提出的方法（任务相关成分分析，TRCA）的扩展，本研究提出了一种新的分析方法，提取任务相关的氧合和脑血容量（CBV）的变化。在TRCA的原始公式中，信号的任务相关性被定义为每个任务块中相同波形的一致外观，从而通过最大化块间协方差来构建任务相关分量。新方法提出，除了最大化块间协方差外，任务相关Δ[HbO]和Δ[HbR]之间的协方差也被最大化（TRCA+）或最小化（TRCA−），从而最大程度地对比氧合和CBV变化。所提出的方法（统称为TRCA±）被制定为矩阵特征值问题，可以使用标准数值方法有效地求解，并使用球囊模型生成的合成数据进行测试，成功地恢复了氧合和CBV分量。然后分析手指敲击任务中感觉运动区和工作记忆（WM）任务中前额叶的fNIRS数据。对于这两项任务，氧合和CBV变化的时间过程和空间图被发现是不同的一致，提供一定的约束条件的参数的气球模型。总之，TRCA可以同时估计任务相关的氧合和CBV变化，从而扩展了fNIRS的适用性。
Although functional near-infrared spectroscopy (fNIRS) has an advantage of simultaneously measuring changes in oxy- and deoxy-hemoglobin concentrations (Δ[HbO] and Δ[HbR]), only few analysis approaches exploit this advantage. As an extension of our recently proposed method (task-related component analysis, TRCA), this study proposes a new analysis method that extracts task-related oxygenation and cerebral blood volume (CBV) changes. In the original formulation of TRCA, task-relatedness of a signal is defined as consistent appearance of a same waveform in every task block, thereby constructing task-related components by maximizing inter-block covariance. The new method proposes that, in addition to maximizing inter-block covariance, the covariance between task-related Δ[HbO] and Δ[HbR] is maximized (TRCA+) or minimized (TRCA−) so that oxygenation and CBV changes are maximally contrasted. The proposed method (collectively called TRCA±) was formulated as a matrix eigenvalue problem, which can be solved efficiently with standard numerical methods, and was tested with a synthetic data generated by a balloon model, successfully recovering oxygenation and CBV components. fNIRS data from sensorimotor areas in a finger-tapping task and from prefrontal lobe in a working-memory (WM) task were then analyzed. For both tasks, the time courses and the spatial maps for oxygenation and CBV changes were found to differ consistently, providing certain constraints in the parameters of balloon models. In summary, TRCA can estimate task-related oxygenation and CBV changes simultaneously, thereby extending the applicability of fNIRS.