A system and methods for transcranial magnetic stimulation, the system including a helmet, a positioning portion, a stimulator and a cooling system, are disclosed. The helmet includes a coil for deep brain magnetic stimulation. The coil has a base portion, and return portions, which may include a protruding return portion and a contacting return portion. The coil is designed to minimize unintended stimulation of portions of the brain, while reducing accumulation of surface charges. The coil is stimulated at several locations and/or at different times so as to focus the electrical field on a specific deep neuronal structure.