IDG/McGovern Institute for Brain Research Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Yes Beijing Normal University NITRC A Pipeline for fNIRS Data Analysis in Naturalistic Paradigms A MATLAB toolbox for preprocessing and quality control of fNIRS data from naturalistic and hyperscanning experiments. It (1) estimates heart rate from raw fNIRS and validates it against ECG; (2) provides a cardiac signal-to-noise-ratio (SNR) framework to objectively evaluate and optimize preprocessing pipelines, benchmarking seven motion-correction schemes and the global-PCA threshold; and (3) compares interpersonal neural synchronization (wavelet transform coherence) across preprocessing schemes, with a 0.1-Hz notch control. A Pipeline for fNIRS Data Analysis in Naturalistic Paradigms Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International, Optical Imaging http://www.nitrc.org/projects/naturalfnirs/, http://www.nitrc.org/projects/naturalfnirs/