A substantial amount of research has focused on the midbrain dopamine system and its role in emotional and motivational behaviors. In diseases in which dopamine function is compromised, patients exhibit a constellation of symptoms, suggesting that the dopamine system plays an important role in the integration of several functions, Subgroups of dopamine neurons receive information from limbic and association areas and project widely throughout cortex and striatum, including motor areas, A dorsal tier of dopamine neurons receive input from the ventral (limbic-related) striatum and from the amygdala and project widely throughout cortex, A more ventrally located group of dopamine cells receives input from both the limbic and association areas of striatum and projects widely throughout the striatum, including the sensorimotor regions. Through these projections, the limbic system has an enormous influence on dopamine output and can therefore affect the emotional and motivational ''coloring'' of a wide range of behaviors.