A few recent studies have suggested approaches to overcome this challenge, e.g. for epileptic discharges9, or based on iterative probe geometry modifications10, which was extended to the voxel-space for an image-based approach11. Herein, we propose an alternative approach to automatically decide optodes positions based on 10–10 and 10–5 systems12 according to a set of brain regions of interest. This method is based on the sensitivity profile from photon transport simulations run on two head atlases (Methods section). The results were compiled into a toolbox to facilitate the definition of optodes positions, the fNIRS Optodes’ Location Decider (fOLD).