Reconstructing functional near-infrared spectroscopy (fNIRS) signals impaired by extra-cranial confounds: An easy-to-use filter method
Reconstructing functional near-infrared spectroscopy (fNIRS) signals impaired by extra-cranial confounds: An easy-to-use filter method
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DOI：
10.1016/j.neuroimage.2014.02.035
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发表时间：
2014-07-15
期刊：
影响因子：
5.7
通讯作者：
Ehlis, A. -C.
中科院分区：
文献类型：
--
作者：
Haeussinger, F. B.;Dresler, T.;Ehlis, A. -C.
功能性近红外光谱（fNIRS）是一种光学神经成像方法，其检测皮质内的氧合和脱氧血红蛋白的时间浓度变化，从而可以推断神经激活。然而，尽管fNIRS是一种非常实用且耐受性良好的方法，特别是在具有方法挑战性的测量情况下（例如，在涉及运动或公开讲话的任务期间），已显示其被非脑、颅外来源的全身性化合物（例如血压、心率的变化）混淆。特别是事件相关的信号模式引起的扩张或收缩的浅额和颞静脉损害检测额叶脑激活引起的认知任务。为了进一步研究这一现象，我们进行了同步fNIRS-fMRI研究应用工作记忆范式（n-back）。通过从皮肤内的fMRI体素提取BOLD信号来获得颅外信号。为了开发一种校正颅外皮肤血流量的滤波器方法，特别是用于由广泛使用的连续波系统记录的fNIRS数据集（具有固定的光电管距离），我们确定了前额上可能具有主要颅外信号贡献的通道。然后从探针组的所有fNIRS通道中减去来自这些通道的平均信号。此外，对数据进行了运动和非诱发系统性伪影校正。应用这些滤波器，我们可以表明，用fNIRS测量额叶脑区的脑激活得到了实质性的改善。所得到的信号比校正前更接近fMRI参数。未来的fNIRS研究测量前额区域的功能性脑激活需要考虑使用不同的滤波器选项来校正干扰的颅外信号。(C)2014 Elsevier Inc. All rights reserved.
Functional near-infrared spectroscopy (fNIRS) is an optical neuroimaging method that detects temporal concentration changes of oxygenated and deoxygenated hemoglobin within the cortex, so that neural activation can be inferred. However, even though fNIRS is a very practical and well-tolerated method with several advantages particularly in methodically challenging measurement situations (e.g., during tasks involving movement or open speech), it has been shown to be confounded by systemic compounds of non-cerebral, extra-cranial origin (e.g. changes in blood pressure, heart rate). Especially event-related signal patterns induced by dilation or constriction of superficial forehead and temple veins impair the detection of frontal brain activation elicited by cognitive tasks. To further investigate this phenomenon, we conducted a simultaneous fNIRS-fMRI study applying a working memory paradigm (n-back). Extra-cranial signals were obtained by extracting the BOLD signal from fMRI voxels within the skin. To develop a filter method that corrects for extra-cranial skin blood flow, particularly intended for fNIRS data sets recorded by widely used continuous wave systems with fixed optode distances, we identified channels over the forehead with probable major extra-cranial signal contributions. The averaged signal from these channels was then subtracted from all fNIRS channels of the probe set. Additionally, the data were corrected for motion and non-evoked systemic artifacts. Applying these filters, we can show that measuring brain activation in frontal brain areas with fNIRS was substantially improved. The resulting signal resembled the fMRI parameters more closely than before the correction. Future fNIRS studies measuring functional brain activation in the forehead region need to consider the use of different filter options to correct for interfering extra-cranial signals. (C) 2014 Elsevier Inc. All rights reserved.