ABSTRACT
Since the mid-1970s, functional near-infrared spectroscopy (fNIRS) has been developing a noninvasive technique to investigate brain cerebral hemodynamic levels associated with brain activity under different stimuli by measuring the absorption coefficient of the nearinfrared (NIR) light between 650 and 950 nm [1-8]. Compared to other functional imaging modalities, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), fNIRS has the advantages of portable, convenience, and low cost, and more importantly, it offers unsurpassed high temporal resolution and quantitative information for both oxyhemoglobin and deoxyhemoglobin, which is essential for revealing rapid changes of dynamic patterns of brain activities including changes of blood oxygen, blood volume, and blood flow.
