The basal nuclei are a collection of gray-matter structures named for their location deep within the base of the forebrain. Functionally, the basal nuclei have a significant role in controlling posture and voluntary movement through connections to the thalamus, cortex, and neighboring basal nuclei structures. In addition to their role in posture and movement, the basal nuclei have connections to limbic system pathways, which govern the expression of various behaviors and motivational states. For the purposes of this section, we will focus on reviewing the structures of the basal nuclei and pathways involved in controlling posture and voluntary movement.