All Topics  
Globus pallidus

 

 
   Email Print
   Bookmark   Link
 

 

Globus pallidus
 
 
  Topics Globus pallidus Topic Home

The globus pallidus (Latin
Latin

Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
 for "pale globe") is a sub-cortical
Cerebral cortex

The cerebral cortex is a structure within the brain that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness....
 structure of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
. It is a major element of the basal ganglia
Basal ganglia

The basal ganglia are a group of Nucleus 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....
 system. In this system, it is a major constituent of the basal ganglia core, which consists of the striatum and its direct targets: globus pallidus and substantia nigra
Substantia nigra

The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in dopaminergic neurons....
. The last two are made up of the same neuronal elements, have a similar main afferent (the dorsal striatum
Striatum

The striatum is a subcortical part of the telencephalon/cerebrum. It is the major input station of the basal ganglia system. Anatomically, the striatum is the caudate nucleus and the putamen....
), have a similar synaptology, and do not receive cortical afferents.






Discussion
Ask a question about 'Globus pallidus'
Start a new discussion about 'Globus pallidus'
Answer questions from other users
Full Discussion Forum



Encyclopedia


The globus pallidus (Latin
Latin

Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
 for "pale globe") is a sub-cortical
Cerebral cortex

The cerebral cortex is a structure within the brain that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness....
 structure of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
. It is a major element of the basal ganglia
Basal ganglia

The basal ganglia are a group of Nucleus 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....
 system. In this system, it is a major constituent of the basal ganglia core, which consists of the striatum and its direct targets: globus pallidus and substantia nigra
Substantia nigra

The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in dopaminergic neurons....
. The last two are made up of the same neuronal elements, have a similar main afferent (the dorsal striatum
Striatum

The striatum is a subcortical part of the telencephalon/cerebrum. It is the major input station of the basal ganglia system. Anatomically, the striatum is the caudate nucleus and the putamen....
), have a similar synaptology, and do not receive cortical afferents. It was recently discovered to play an active part in pre-filtering external stimuli and may help reduce the amount of irrelevant information the brain needs to store.

History of name

The origin of the name is not established. It was known by Dejerine (1906) but not by Santiago Ramón y Cajal
Santiago Ramón y Cajal

Santiago Ram?n y Cajal was a Spanish people histology, physician, pathologist and Nobel laureate. His pioneering investigations of the microscopic structure of the brain were so original and influential that he is considered by many to be the greatest neuroscientist of all time....
 (1909-1911). As the elements in no way have the shape of a globe, Foix and Nicolesco (1925), the Vogts (1941), Crosby et all.(1962) followed by the Terminologia anatomica proposed the simpler term (neuter adjective) of pallidum (pale). During a long period the globus pallidus was unduly linked to the putamen in the lentiform nucleus
Lentiform nucleus

The lentiform nucleus or lenticular nucleus comprises the putamen and the globus pallidus within the basal ganglia. It is a large, cone-shaped mass of gray matter just lateral to the internal capsule....
 (nucleus lenticularis or lentiformis). This was a heterogeneous anatomical entity that is part of the striatum
Striatum

The striatum is a subcortical part of the telencephalon/cerebrum. It is the major input station of the basal ganglia system. Anatomically, the striatum is the caudate nucleus and the putamen....
 rather than the pallidum. The link with the substantia reticulata was stressed very early on due to the similarities in dendritic arborisation, but in spite of solid arguments this link is still not widely accepted. The two however constitute a particular set of the basal ganglia system (the pallidonigral set).

Parts

In primate
Primate

A primate is a member of the biological order Primates , the group that contains lemurs, the Aye-aye, Lorisidaes, galagos, tarsiers, monkeys, and apes, with the last category including humans....
s, the dorsal pallidum, or globus pallidus, is divided into two segments by the medial medullary lamina. A frequent nomenclature uses the adjectives internal and external to refer to the two divisions of the globus pallidus. The medial segment of the dorsal pallidum, internal globus pallidus (GPi), and lateral division of the dorsal pallidum, external globus pallidus (GPe), are thus the two parts of the dorsal pallidum that are two closed nuclei surrounded everywhere by myelinic walls.

The ventral pallidum lies within the substantia innominata (Latin for un-named substance) and receives efferent connections from the ventral striatum
Striatum

The striatum is a subcortical part of the telencephalon/cerebrum. It is the major input station of the basal ganglia system. Anatomically, the striatum is the caudate nucleus and the putamen....
 (nucleus accumbens
Nucleus accumbens

The nucleus accumbens , also known as the accumbens nucleus or as the nucleus accumbens septi , is a collection of neurons within the forebrain....
 and olfactory tubercle). The ventral pallidum projects to the dorsomedial nucleus of the dorsal thalamus
Thalamus

The thalamus is a pair and symmetric part of the brain. It constitutes the main part of the diencephalon....
, which projects to the prefrontal cortex. The ventral pallidum also projects to the pedunclopontine nucleus and tegmental motor area. The function of the ventral pallidum is limbic-somatic motor interface for the planning and inhibition of movements from the dorsal striatopallidal complex.

Structure

Pallidal nuclei are made up of the same neuronal components. In primates, almost all pallidal neurons are very large, parvalbumin
Parvalbumin

Parvalbumin is a calcium binding albumins protein with low molecular weight .It has three EF hand motifs and is structurally related to calmodulin and troponin C....
 positive, with very large dendritic arborizations. These have the peculiarity of having the three-dimensional shape of flat discs, parallel to one another, parallel to the border of the pallidum and perpendicular to the afferent striatopallidal axons. There are only a few small local circuitry neurons.

The globus pallidus is traversed by the numerous myelin
Myelin

Myelin is an electrically-insulating dielectric material that forms a layer, the myelin sheath. Usually, myelin surrounds only the axon of a neuron....
ated axons of the striato-pallidonigral bundle that give it the pale appearance from which it is named.

The ultrastructure is very peculiar, as the long dendrites are everywhere, without discontinuity, covered by synapses.

Pallidonigral pacemaker


The two pallidal nuclei and the two nigral (pars compacta and pars reticulata) parts constitute a high-frequency autonomous pacemaker (see primate basal ganglia system#Pallido-nigral_set_and_pacemaker
Primate basal ganglia system

The primate basal ganglia system is a symmetrical major cerebral system that has only recently been recognized. In the past, part of it was presented as motor system or "extrapyramidal", complementary to the corticospinal tract system....
)

Common afferents

The two parts receive successively a large quantity of GABAergic axonal terminal arborisations from the striatum
Striatum

The striatum is a subcortical part of the telencephalon/cerebrum. It is the major input station of the basal ganglia system. Anatomically, the striatum is the caudate nucleus and the putamen....
 through the dense striato-pallidonigral bundle. The synaptology is very peculiar (see primate basal ganglia system
Primate basal ganglia system

The primate basal ganglia system is a symmetrical major cerebral system that has only recently been recognized. In the past, part of it was presented as motor system or "extrapyramidal", complementary to the corticospinal tract system....
).The striatal afference contribute for more than 90% of synapses. The two pallidal nuclei receives dopaminergic axons from the pars compacta of the substantia nigra.

Basal Ganglia Coronal Sections Large

See also

  • Lentiform nucleus
    Lentiform nucleus

    The lentiform nucleus or lenticular nucleus comprises the putamen and the globus pallidus within the basal ganglia. It is a large, cone-shaped mass of gray matter just lateral to the internal capsule....


Additional images


External links