The basal nuclei (Figure 12.11) (sometimes misnamed the basal ganglia [Q: why is this incorrect?]) consist of a group of structures with both gray and white matter which in various ways modify motor functions coming from the cerebral cortex. Its structures include the caudate nucleus, putamen, and globus pallidus, and by some authors the substantia nigra and amygdaloid nucleus. (Marieb considers the substantia nigra part of the midbrain). The basal nuclei function in association with the corticospinal system to control complex patterns of motor activity. When there is serious damage the basal nuclei the motor cortex can no longer provide the patterns for many skilled and repetitive actions. Included are: writing letters of the alphabet, using scissors, hammering nails, shooting a basketball, passing a football, shoveling dirt, controlled eye movements and many others. Several circuits connect the basal nuclei with the motor association areas, sensory association areas, and the motor cortex in loops which provide both positive and negative feedback.