Department of Electrical and Electronics Engineering, Boğaziçi University, Istanbul, Turkey.
IEEE Trans Biomed Eng. 2010 Mar;57(3):761-8. doi: 10.1109/TBME.2009.2020792. Epub 2009 Apr 28.
Functional near-infrared spectroscopy (fNIRS) is an optical imaging method, which monitors the brain activation by measuring the successive changes in the concentration of oxy- and deoxyhemoglobin in real time. In this study, we present a method to investigate the functional connectivity of prefrontal cortex (PFC) Sby applying a Gauss-Markov model to fNIRS signals. The hemodynamic changes on PFC during the performance of cognitive paradigm are measured by fNIRS for 17 healthy adults. The color-word matching Stroop task is performed to activate 16 different regions of PFC. There are three different types of stimuli in this task, which can be listed as incongruent stimulus (IS), congruent stimulus (CS), and neutral stimulus (NS), respectively. We introduce a new measure, called "information transfer metric" (ITM) for each time sample. The behavior of ITMs during IS are significantly different from the ITMs during CS and NS, which is consistent with the outcome of the previous research, which concentrated on fNIRS signal analysis via color-word matching Stroop task. Our analysis shows that the functional connectivity of PFC is highly relevant with the cognitive load, i.e., functional connectivity increases with the increasing cognitive load.
功能近红外光谱（fNIRS）是一种光学成像方法，通过实时测量氧合和脱氧血红蛋白浓度的连续变化来监测大脑激活。在这项研究中，我们提出了一种应用高斯-马尔可夫模型研究前额叶皮层（PFC）功能连接的方法。通过 fNIRS 测量 17 名健康成年人在执行认知范式期间 PFC 的血液动力学变化。执行颜色-词匹配 Stroop 任务以激活 PFC 的 16 个不同区域。该任务中有三种不同类型的刺激，分别为不一致刺激（IS）、一致刺激（CS）和中性刺激（NS）。我们为每个时间样本引入了一个新的度量，称为“信息传递度量”（ITM）。IS 期间的 ITM 行为与 CS 和 NS 期间的 ITM 行为明显不同，这与之前集中于通过颜色-词匹配 Stroop 任务分析 fNIRS 信号的研究结果一致。我们的分析表明，PFC 的功能连接与认知负荷高度相关，即功能连接随认知负荷的增加而增加。
