Basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Mammalian basal ganglia are associated with a variety of functions: motor control, cognition, emotions, and learning. In modern use the term 'ganglia' is in this instance considered a misnomer; 'ganglion' refers to concentrations of neural nuclei in the periphery only (for example those of the autonomic nervous system), and the term 'basal nuclei' is preferred.
The five individual nuclei that make up the primate basal ganglia, along with their major subdivisions, are:
the striatum, which consists of
external segment of the globus pallidus (GPe)
internal segment of the globus pallidus (GPi)
subthalamic nucleus (STN)
substantia nigra (SN)
substantia nigra pars compacta (SNc)
substantia nigra pars reticulata (SNr)
substantia nigra pars lateralis (SNl)
There are 2 sets of basal ganglia in the mammalian brain, mirrored in the left and right hemispheres.
Two coronal sections are used to show the basal ganglia; the STN and substantia nigra lie deeper back in the brain (more caudal). Images show two schematic coronal cross-sections of the human brain with nuclei of the basal ganglia labeled on the right side.
Functionally, the basal ganglia consist of a series of circuits, such as skeletomotor, limbic and occulomotor circuits. Each circuit projects to specific nuclei within the basal ganglia and its projections e.g. the skeletomotor circuit projects to the ventral lateral, lateral ventral anterior and centromedian thalamic nuclei.
Basal ganglia. (2009, May 19). In Wikipedia, The Free Encyclopedia. Retrieved 22:08, May 19, 2009, from http://en.wikipedia.org/w/index.php?title=Basal_ganglia&oldid=291041764