Motor Systems II: Basal Ganglia and Movement Disorders

Abstract

The term “basal ganglia” originally included the deep telencephalic nuclei: the caudate, putamen, globus pallidus, the claustrum, and nucleus accumbens. The globus pallidus and putamen are lens shaped and are called lenticular nuclei. Collectively the putamen and caudate are called the corpus striatum. Additional structures now included within this group are the substantia nigra, the subthalamic nuclei, the ventral tegmental area and the ventral pallidum. The caudate and putamen have the same structure and are continuous anteriorly. The globus pallidus has two sectors: a medial or inner and a lateral or outer. The substantia nigra has two components: a ventral pars reticularis which is identical in structure and function to the medial sector of the globus pallidus and a dorsal darkly staining component the pars compacta which contains large dopamine and melanin containing neurons.