Using 18F-FDG PET/CT, chronic PSES have been shown to increase activity of the amygdala which has been associated with increased activity of the bone marrow and spleen as well as arterial inflammation. It is hypothesized that sympathetic afferents stimulate hematopoiesis in the bone marrow, and possibly spleen, which results in increased migration of immune cells to arteries and may lead to cardiovascular disease.