A quantitative comparison of NIRS and fMRI across multiple cognitive tasks

► We performed simultaneous NIRS/fMRI recording during motor and cognitive tasks. ► NIRS signals have weaker signal-to-noise (SNR) ratio, but correlate with fMRI. ► SNR and scalp-brain distance contributed to variability in NIRS/fMRI correlations. ► NIRS correlated with BOLD from an ellipse between emitter and detector (~ 14mm depth).