Experimental and clinical applications of functional near infrared spectroscopy and functional diffuse correlation spectroscopy

Abstract

Functional Near Infrared Spectroscopy (fNIRS) has been used in an exponentially increasing number of studies over the years in areas such as cognitive and clinical neuroscience, brain-computer interface, neuroergonomics. Compared to a hemodynamic response-based technique such as functional magnetic resonance imaging, it is a preferred functional neuroimaging modality due to its portability, ease of use, tolerance to motion artifacts and higher temporal resolution. Functional Diffusion Correlation Spectroscopy (fDCS), which has a similar physical principle with fNIRS, is a technique based on measuring cerebral blood flow (CBF) from near-infrared light intensity-basedautocorrelation obtained from photon detectors. While fNIRS gives us information about the oxy and deoxyhemoglobin concentrations it measures and tissue oxygen metabolism, fDCS gives us more local microvascular CBF information. According to studies, fDCS is a system that is three times more sensitive to brain-to-scalp sensitivity than fNIRS. When used together with fNIRS, it also enables the estimation of a neurologically critical biomarker such as the cerebral metabolic rate of oxygen (CMRO2). In this talk, the applications of fNIRS on various psychiatric and neurological populations and the fDCS system will be introduced in general, and functional neuroimaging and neurological applications of fDCS will be mentioned.