A quantitative comparison of NIRS and fMRI across multiple cognitive tasks

Abstract

Near infrared spectroscopy (NIRS) is an increasingly popular technology for studying brain function. NIRS presents several advantages relative to functional magnetic resonance imaging (fMRI), such as measurement of concentration changes in both oxygenated- and deoxygenated hemoglobin, finer temporal resolution, and ease of administration, as well as disadvantages, most prominently inferior spatial resolution and decreased signal-to-noise ratio (SNR). While fMRI has become the gold standard for in vivo imaging of the human brain, in practice NIRS is a more convenient and less expensive technology than fMRI. It is therefore of interest to many researchers how NIRS compares to fMRI in studies of brain function. In the present study we scanned participants with simultaneous NIRS and fMRI on a battery of cognitive tasks, placing NIRS probes over both frontal and parietal brain regions. We performed detailed comparisons of the signals in both temporal and spatial domains. We found that NIRS signals have significantly weaker SNR, but are nonetheless often highly correlated with fMRI measurements. Both SNR and the distance between the scalp and the brain contributed to variability in the NIRS/fMRI correlations. In the spatial domain, we found that a photon path forming an ellipse between the NIRS emitter and detector correlated most strongly with the BOLD response. Taken together these findings suggest that, while NIRS can be an appropriate substitute for fMRI for studying brain activity related to cognitive tasks, care should be taken when designing studies with NIRS to ensure that: 1) the spatial resolution is adequate for answering the question of interest and 2) the design accounts for weaker SNR, especially in brain regions more distal from the scalp.

The self-regulating brain and neurofeedback: Experimental science and clinical promise

“…FNIRS technology typically uses a portable cap with approximately 50 channels to measure the concentration of deoxygenated blood in superficial brain areas. While fNIRS probes the same underlying hemodynamics as fMRI (Cui, Bray, Bryant, Glover, & Reiss, 2011), each method possesses distinct strengths and weaknesses when applied to neurofeedback. On the one hand, fNIRS is relatively inexpensive, resistant to movement artifacts, and highly portable.…”

Imagined Hand Clenching Force and Speed Modulate Brain Activity and Are Classified by NIRS Combined With EEG

“…Compared with EEG, NIRS is an active measuring method to emit energy into tissue and infer functional neural activity from metabolic activity, which is measured by changing light absorption [1]- [3] and is a relatively new approach in neuroscience and brain-computer interfaces [4]- [8]. With fNIRS, tissue function alone produces the imaged signal [9].…”

Tissue phantom-based breast cancer detection using continuous near-infrared sensor

“…Thus the concentrations of these mediums can be calculated with the transmitted intensity. 10 Considering the grading of hemoglobin concentration in breast tumor, the resolution of blood oxygen concentration should be no less than 10 mol/L to make sure earlystage tumor to be identified by the system.…”