The phrase "focal region" refers to a specific area or point that is the center of attention or focus. It is a place or region where the focus or main point of interest is situated. Full definition
«Japan has historically suffered damage from huge earthquakes, whose focal regions usually lie beneath the seafloor,» says hydrographer Mariko Sato of the Japanese Coast Guard, whose team compiled the seafloor data, published online May 19 in Science. (scientificamerican.com)
«We saw a more severe form of the generalized muscle cell death usually seen in muscular dystrophy, but also more focal regions of cardiac muscle cell damage as if there were some type of an infarct or smooth muscle dysfunction,» said Campbell. (hhmi.org)