Defining precisely the position of active regions obtained from functional neuroimaging studies is challenging due to the functional and anatomical variability across subjects. Traditional volumetric normalization techniques ignore the geometry of the cortex and use a relatively imprecise three-dimensional coordinate system. In this study we propose an alternative method that relates the position of functional regions on the cortical surface to the positions of the main macro-anatomical structures, the sulci. Our approach consists of using the nearest sulci to build a local referential in which the position of a region is defined. This triangulation approach improves the localization of brain regions involved in various cognitive tasks.