Fig. 4.

fNIRS montage and schematic diagram of data collection. Panel (A) plots the anatomical locations of light sources (S1 – S8, red dots) and detectors (D1 - D8, blue dots) and the connections between them that provide fNIRS channels. The locations of sources and detectors on the 10-10 system were labeled in light blue. Only the left hemisphere is shown here, with a symmetric montage on the right. Green circles show the locations where short channels (8 mm) are located. Panel (B) shows the sensitivity map (with a log10 unit of mm⁻¹) of near-infrared light in measuring local chromophores in two regions of interest (ROIs), i.e., the lateral frontal cortex (LFC), and auditory cortex (AC). The more reddish color refers to the better sensitivity; the map was generated using AtlasViewer toolbox (Aasted et al., 2015). Panel (C) shows the timeline of a speech perception block in the fNIRS session, which started with a baseline, followed by a block of 5 sentences, and then a response period when participants responded to the sentence on the monitor by clicking mouse buttons. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)