In this study unit you will learn how to:
- Provide a general definition of the basal ganglia.
- Describe the different components of the basal ganglia.
- Explain the function of the basal ganglia.
- Understand the connections and pathways of the basal ganglia.
The basal ganglia, or basal nuclei, are a group of masses of gray matter found deep within the white matter of each cerebral hemisphere. The components of basal ganglia are the caudate nucleus, putamen, and globus pallidus. The subthalamic nucleus and substantia nigra are not anatomically part of the basal ganglia but are functionally connected and related to this system.
To avoid confusion, it is important to define the different terms used when referring to the basal ganglia (please note though, that you may see different terminology used in other resources):
- The term corpus striatum refers to the caudate nucleus, putamen and globus pallidus. It is, in other words, another term to describe the three basal nuclei.
- The term dorsal striatum (also known as neostriatum) refers to the caudate nucleus and putamen. Those two structures are functionally connected, have the same cytoarchitecture and thus can be considered as a single entity (the neostriatum).
- The term paleostriatum refers to the globus pallidus.
- The ventral striatum includes the nucleus accumbens and olfactory tubercle - these structures are considered to be a part of the limbic system.
- The term lentiform nucleus is a descriptive term which is used for the putamen and the globus pallidus. These two structures, although topographically related, have different functions. This is the reason why the term lentiform nucleus is not used regularly in clinical practice.
The basal ganglia play a crucial role in the modulation of voluntary movements. Dysfunction of these structures can lead to several neurologic conditions broadly known as movement disorders.
If you want to learn more about the basal ganglia, check our video below!
Take a quiz
Solidify your knowledge of the basal ganglia by taking the following quiz.
Challenge yourself further, with this customized quiz about all the subcortical structures.
Review all the structures you learned today in the gallery below.
|Definition||Group of subcortical nuclei that fine-tune the voluntary motor activity|
Functionally related structures:
|Function||Planning and modulation of movement, memory, eye movements, reward processing, motivation|
Motor loop (movement control):
Direct pathway (excitatory, movement initiation)
Indirect pathway (inhibitory, movement termination)
Hyperdirect pathway (inhibitory, baseline inhibition, inhibition of extemporaneous movements)
Learning loop (learning of movements)
Limbic loop (emotional expression of movements)
Oculomotor loop (eye movements)