The selected image file will be loaded in the toolbox, resampled to 2 × 2 × 2 mm3, and the toolbox will look for any overlap of its voxels presenting values greater than 0 with those of each fNIRS channel extent. For each channel, the specificity to the loaded region of interest will be calculated (Equation 3) and the optodes related to channels surviving the minimum specificity threshold will be displayed in the main panel.