Sign Up for a Free Account
  • Updated 03.18.2024
  • Released 04.04.2001
  • Expires For CME 03.18.2027

Basal ganglia: functional anatomy and neuropharmacology



The authors describe the functional anatomy of the basal ganglia, with an emphasis on extensions of the standard “rate” model that have evolved recently. They also describe basal ganglia physiology including changes observed in pathologic states, highlighting Parkinson disease. Finally, potential mechanisms of basal ganglia function and dysfunction are discussed.

Key points

• The basal ganglia are a set of subcortical gray matter structures associated with motor, cognitive, and limbic functions. The canonical structures are the caudate nucleus, putamen, globus pallidus (interna and externa), substantia nigra (pars compacta and pars reticulata), and subthalamic nucleus.

• These structures can be divided into afferent areas receiving information (primarily cortical), efferent nuclei sending information to the thalamus, and intrinsic nuclei that act as relays between the two.

• Basal ganglia disorders (movement disorders) are heterogenous syndromes mechanistically involving the basal ganglia. Parkinson disease and essential tremor are examples of conditions characterized by physiological basal ganglia changes.

• Advances in animal models and deep brain stimulation continue to improve our understanding of basal ganglia networks.

• Despite much progress, a comprehensive model of basal ganglia function that explains its normal and pathologic function remains elusive.

Historical note and terminology

David Ferrier, in a book titled The Functions of the Brain, described the corpus striatum and other subcortical structures serving as a connection between cortical structures and the peripheral nervous system (46). The term “basal” refers to the location of this group of structures; however, “basal nuclei” would be more accurate than “basal ganglia.” Despite this, the historical terminology persists. Models for the “direct and indirect pathways” emerged in the 1990s, and our understanding of the basal ganglia pathways has built upon, expanded, and challenged this perspective. This understanding has been challenging because disorders associated with basal ganglia pathology have presented a puzzle for conventional clinicopathologic correlations. Unlike other CNS subsystems, such as the cerebellum and its connections where motor deficits are often similar regardless of the anatomic locus of pathologies, lesions of distinct basal ganglia subregions cause different clinical syndromes. The best example is the contrast between the paucity of spontaneous movement associated with parkinsonism and the excess involuntary movements associated with the chorea-athetosis-ballism spectrum. Some crude correlations based on gross pathology were possible (Table 1), but an integrated understanding of the bases for the diverse phenomena associated with basal ganglia pathology continues to emerge.

Many investigators have contributed to an improved understanding of the basal ganglia; listing everyone involved would be beyond the scope of this review. Some notable examples include Samuel Thomas von Soemmerring (1755-1830), who was the first to describe the substantia nigra. He is probably best known for his doctoral thesis on the 12 cranial nerves (127). Karl Friedrich Burdach (1776- 1847) provided a detailed anatomical description of the brain in his book (Vom Baue und Leben des Gehirns [Of Structure and Life of the Brain]). Importantly, the terminology used by Burdach in his description of the basal ganglia persists (eg, the putamen, lentiform nucleus, and globus pallidus), although not all the structures he named were discovered by him (111). The subthalamic nucleus was not noted by Burdach; it belonged to Jean Bernard Luys, whose name is sometimes lent to this structure (corpus Luysii). Luys studied the neural pathways from the subthalamic nucleus and linked it to automatic motor activity. He was also the first to describe the different functional units of the thalamus (125).

Table 1. Localization of Pathology within the Basal Ganglia

Clinical phenomenon


Parkinson disease

Striatum or subthalamic nucleus
Substantia nigra-nigrostriatal projection

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125