To compare fcNIRS and task-based NIRS language mapping, NIRS data were acquired at rest and during an expressive language task in a single recording session. For both fcNIRS and task-based NIRS, data acquisition was performed using a frequency-domain device (Imagent, ISS Inc., Illinois) equipped with 8 detectors and 64 sources (32 at 690-nm wavelength and 32 at 830 nm). Optical intensity (DC), modulation amplitude (AC), and phase data were obtained at an acquisition rate of 19.5312 Hz. Light sources and detectors were held in place using a comfortable, age-adapted helmet. Source–detector distances were set between 2 and 5 cm, optimizing recording of the brain signal from various depths in the regions of interest. A standard montage was created and adapted for each age group according to the 10–20 system and the corresponding Brodmann areas (BA). NIRS fibers covered bilateral frontal and temporal areas so as to record brain activity in anterior and posterior language-related regions, Broca’s (BA 44 and 45) and Wernicke’s (BA 22, 39, and 40) areas, respectively [Fig. 1(a)], and their right hemisphere counterparts. For each participant, the accurate localization of each source and detector, as well as four fiducial points (nasion, left and right preauriculars, and tip of the nose), was digitized and recorded with the stereotaxic system Brainsight™ Frameless 39 (Rogue Research Inc., Montreal, Quebec, Canada) allowing for individual registration and reconstitution of the montage on an MRI template (Colin27, see Ref. 47).