Variability of (functional) hemodynamics as measured with simultaneous fNIRS and fMRI during intertemporal choice

► Consistency in prefrontal fNIRS and fMRI intertemporal choice group activation ► High individual variability in fNIRS signals and fNIRS-fMRI correlations ► fNIRS activation is impacted by reached gray matter volume and scalp-cortex distance. ► fMRI scalp signal fluctuations correlate with the temple area fNIRS signals. ► Trait sensitivity to reward increases fNIRS~scalp fMRI correlations.