Globus pallidus

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Globus pallidus
Globus pallidus.svg
Globus pallidus (in red) shown within the brain
DA-loops in PD.svg
Dopamine-loops in Parkinson's disease
Details
Part of Basal ganglia
Identifiers
Latin globus pallidus
Acronym(s)GP
MeSH D005917
NeuroNames 231
NeuroLex ID birnlex_1234
TA98 A14.1.09.518
TA2 5569
FMA 61835
Anatomical terms of neuroanatomy

The globus pallidus (GP), also known as paleostriatum or dorsal pallidum, [1] is a major component of the subcortical basal ganglia in the brain. It consists of two adjacent segments, one external (or lateral), known in rodents simply as the globus pallidus, and one internal (or medial). It is part of the telencephalon, but retains close functional ties with the subthalamus in the diencephalon – both of which are part of the extrapyramidal motor system. [2]

Contents

The globus pallidus receives principal inputs from the striatum, and principal direct outputs to the thalamus and the substantia nigra. The latter is made up of similar neuronal elements, has similar afferents from the striatum, similar projections to the thalamus, and has a similar synaptology. Neither receives direct cortical afferents, and both receive substantial additional inputs from the intralaminar thalamic nuclei.

Globus pallidus is Latin for "pale globe".

Structure

Transverse section of the globus pallidus from a structural MR image. Globus Pallidus structural MRI.png
Transverse section of the globus pallidus from a structural MR image.

Pallidal nuclei are made up of the same neuronal components. In primates, almost all pallidal neurons are very large, parvalbumin-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 [3] and perpendicular to the afferent striatopallidal axons. [4] There are only a few small local circuitry neurons.

The globus pallidus is traversed by the numerous myelinated axons of the striatopallidonigral 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. [5] [6]

Parts

Microscopic image of the external globus pallidus (lower left of image) and putamen (upper right of image). H&E-LFB stain. Globus pallidus and putamen - very low mag.jpg
Microscopic image of the external globus pallidus (lower left of image) and putamen (upper right of image). H&E-LFB stain.

In primates, the globus pallidus is divided into two parts by a thin medial medullary lamina. [7] These are the internal globus pallidus (GPi) and the external globus pallidus (GPe); both are composed of closed nuclei surrounded by myelinic walls.

The ventral pallidum lies within the substantia innominata (Latin for unnamed substance) and receives efferent connections from the ventral striatum (the nucleus accumbens and the olfactory tubercle). It projects to the dorsomedial nucleus of the dorsal thalamus, which, in turn, projects to the prefrontal cortex; it also projects to the pedunculopontine nucleus and tegmental motor areas. Its function is to serve as a limbic-somatic motor interface, and it is involved in the planning and inhibition of movements from the dorsal striatopallidal complex.

Function

The globus pallidus is a structure in the brain involved in the regulation of voluntary movement. [8] It is part of the basal ganglia, which, among many other functions, regulate movements that occur on the subconscious level.

The globus pallidus has a predominantly inhibitory effect on movement regulation, balancing cerebellar excitation. Pulsatile and regular interaction between these complementary systems allows smooth and controlled movement. Imbalances can result tremors, jerks, dystonia, chorea and progressive motor weakness ending in diaphragmatic dysfunction, with the most common cause of mortality in most neurodegenerative disorders being aspiration pneumonia.

The basal ganglia acts on a subconscious level, requiring no conscious effort to function. When someone makes a decision to engage in an activity such as petting a dog, for example, these structures help to regulate the movement to make it as smooth as possible, and to respond to sensory feedback. Likewise, the globus pallidus is involved in the constant subtle regulation of movement that allows people to walk and engage in a wide variety of other activities with a minimal level of disruption.[ citation needed ]

Pallidonigral pacemaker

The two pallidal nuclei and the two parts of the substantia nigra (the pars compacta and pars reticulata) constitute a high-frequency autonomous pacemaker. [9] (see primate basal ganglia#Pallidonigral set and pacemaker)

Common afferents

The two parts receive successively a large quantity of GABAergic axonal terminal arborisations from the striatum through the dense striato-pallidonigral bundle. The synaptology is very peculiar (see primate basal ganglia system). [5] [6] The striatal afferents contribute more than 90% of synapses.[ citation needed ] The two pallidal nuclei receive dopaminergic axons from the pars compacta of the substantia nigra.

Coronal slices of human brain showing the basal ganglia. ROSTRAL: striatum, globus pallidus (GPe and GPi) CAUDAL: subthalamic nucleus (STN), substantia nigra (SN) Basal-ganglia-coronal-sections-large.png
Coronal slices of human brain showing the basal ganglia.
ROSTRAL: striatum, globus pallidus (GPe and GPi)
CAUDAL: subthalamic nucleus (STN), substantia nigra (SN)
Overview of the main circuits of the basal ganglia. Globus pallidus externa and interna are shown in green. Picture shows 2 coronal slices that have been superimposed to include the involved basal ganglia structures, with + and - signs at the point of the arrows indicating, respectively, whether the pathway is excitatory or inhibitory in effect. @media screen{html.skin-theme-clientpref-night .mw-parser-output div:not(.notheme)>.tmp-color,html.skin-theme-clientpref-night .mw-parser-output p>.tmp-color,html.skin-theme-clientpref-night .mw-parser-output table:not(.notheme) .tmp-color{color:inherit!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output div:not(.notheme)>.tmp-color,html.skin-theme-clientpref-os .mw-parser-output p>.tmp-color,html.skin-theme-clientpref-os .mw-parser-output table:not(.notheme) .tmp-color{color:inherit!important}} Green arrows refer to excitatory glutamatergic pathways, red arrows refer to inhibitory GABAergic pathways and turquoise arrows refer to dopaminergic pathways that are excitatory on the direct pathway and inhibitory on the indirect pathway. Basal ganglia circuits.svg
Overview of the main circuits of the basal ganglia. Globus pallidus externa and interna are shown in green. Picture shows 2 coronal slices that have been superimposed to include the involved basal ganglia structures, with + and – signs at the point of the arrows indicating, respectively, whether the pathway is excitatory or inhibitory in effect. Green arrows refer to excitatory glutamatergic pathways, red arrows refer to inhibitory GABAergic pathways and turquoise arrows refer to dopaminergic pathways that are excitatory on the direct pathway and inhibitory on the indirect pathway.

Pathway

This area of the basal ganglia receives input from another area, called the striatum, which has two parts, the caudate nucleus and the putamen. This data is routed to the thalamus, either directly or indirectly. In the case of the interna, one area of the globus pallidus, the structure can feed directly to the thalamus. The externa, which lies on the outside of this structure, feeds information to the interna, where it can be passed on to the thalamus.

Disease

Infarction of the globus pallidus can be seen with anoxic brain injury, carbon monoxide poisoning and drug overdoses (MDMA and heroin), with the insult classically being bilateral. Bilateral calcification can occur in a lentiform shape with aggressive parenteral nutrition. Encephalopathy, as can occur with cirrhosis or Leigh syndrome, also causes globus pallidus abnormalities, making them bright on MRI T1 sequences in liver disease and on bright on T2 sequences with Leigh syndrome. Additional substances that can accumulate in the basal ganglia include heavy metals (such as gadolinium, iron and copper), calcium and amyloid with hypothyroidism.

Clumps of disorganized nerve tissue, can accumulate inside the globus pallidus with neurofibromatosis type I, causing severe neurologic dysfunction. The pallidus can also be destroyed by rare metabolic disorders such as PKAN, methylmalonic acidemias and maple syrup urine disease. [10]

Though damage to the globus pallidus can cause movement disorders, diseases like Parkinson's and essential tremor can paradoxically be treated by surgically inducing lesions in the nuclei using ultrasound, Gamma knife, or more rarely open surgery. The nucleus can also be artifically stimulated using deep brain stimulation in which a battery pack is inserted into the chest wall and electrical leads run up the neck and into the brain from the back of the skull. The aim of these procedures is to reduce involuntary muscle tremors and improve extrapyramidal symptoms associated with neurodegeneration, though they can impact intellectual function and cause dysarthria. [11]

History

The origin of the name is not established. It was used by Joseph Dejerine (1906) but not by Santiago Ramón y Cajal (1909–1911).

As the elements in no way have the shape of a globe, throughout the 20th century scientists proposed a simpler term (a neuter adjective), pallidum (meaning "pale"). Propositions include those by Foix and Nicolesco (1925), the Vogts (1941), Crosby et al. (1962) and the Terminologia Anatomica .

For a long time the globus pallidus was linked to the putamen and termed the lentiform nucleus (nucleus lenticularis or lentiformis), a heterogeneous anatomical entity that is part of the striatum rather than the pallidum. The link with the substantia nigra pars reticulata was stressed very early on due to the similarities in dendritic arborisation (and they are sometimes known as the pallidonigral set) but, in spite of strong evidence, this association remains controversial.

Animal Studies

In rodents, the globus pallidus internus is also known as the entopeduncular nucleus.[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Putamen</span> Round structure at the base of the forebrain

The putamen is a subcortical nucleus with a rounded structure, in the basal ganglia nuclear group. It is located at the base of the forebrain and above the midbrain.

<span class="mw-page-title-main">Striatum</span> Nucleus in the basal ganglia of the brain

The striatum or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamatergic and dopaminergic inputs from different sources; and serves as the primary input to the rest of the basal ganglia.

<span class="mw-page-title-main">Basal ganglia</span> Group of subcortical nuclei involved in the motor and reward systems

The basal ganglia (BG) or basal nuclei are a group of subcortical nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into external and internal regions, and in the division of the striatum. Positioned at the base of the forebrain and the top of the midbrain, they have strong connections with the cerebral cortex, thalamus, brainstem and other brain areas. The basal ganglia are associated with a variety of functions, including regulating voluntary motor movements, procedural learning, habit formation, conditional learning, eye movements, cognition, and emotion.

In neuroanatomy, a nucleus is a cluster of neurons in the central nervous system, located deep within the cerebral hemispheres and brainstem. The neurons in one nucleus usually have roughly similar connections and functions. Nuclei are connected to other nuclei by tracts, the bundles (fascicles) of axons extending from the cell bodies. A nucleus is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up as a region of gray matter, often bordered by white matter. The vertebrate brain contains hundreds of distinguishable nuclei, varying widely in shape and size. A nucleus may itself have a complex internal structure, with multiple types of neurons arranged in clumps (subnuclei) or layers.

<span class="mw-page-title-main">Nigrostriatal pathway</span> Bilateral pathway in the brain

The nigrostriatal pathway is a bilateral dopaminergic pathway in the brain that connects the substantia nigra pars compacta (SNc) in the midbrain with the dorsal striatum in the forebrain. It is one of the four major dopamine pathways in the brain, and is critical in the production of movement as part of a system called the basal ganglia motor loop. Dopaminergic neurons of this pathway release dopamine from axon terminals that synapse onto GABAergic medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), located in the striatum.

<span class="mw-page-title-main">Direct pathway</span> Neural pathway that executes voluntary movements

The direct pathway, sometimes known as the direct pathway of movement, is a neural pathway within the central nervous system (CNS) through the basal ganglia which facilitates the initiation and execution of voluntary movement. It works in conjunction with the indirect pathway. Both of these pathways are part of the cortico-basal ganglia-thalamo-cortical loop.

<span class="mw-page-title-main">Indirect pathway</span> Neuronal circuit that suppresses unwanted movements

The indirect pathway, sometimes known as the indirect pathway of movement, is a neuronal circuit through the basal ganglia and several associated nuclei within the central nervous system (CNS) which helps to prevent unwanted muscle contractions from competing with voluntary movements. It operates in conjunction with the direct pathway.

<span class="mw-page-title-main">Subthalamic nucleus</span> Small lens-shaped nucleus in the brain

The subthalamic nucleus (STN) is a small lens-shaped nucleus in the brain where it is, from a functional point of view, part of the basal ganglia system. In terms of anatomy, it is the major part of the subthalamus. As suggested by its name, the subthalamic nucleus is located ventral to the thalamus. It is also dorsal to the substantia nigra and medial to the internal capsule.

The pars reticulata (SNpr) is a portion of the substantia nigra and is located lateral to the pars compacta. Most of the neurons that project out of the pars reticulata are inhibitory GABAergic neurons.

<span class="mw-page-title-main">Subthalamus</span> Structure of the brain

The subthalamus or ventral thalamus is a part of the diencephalon. Its most prominent structure is the subthalamic nucleus. The subthalamus connects to the globus pallidus, a subcortical nucleus of the basal ganglia.

<span class="mw-page-title-main">Substantia innominata</span>

The substantia innominata, also innominate substance or substantia innominata of Meynert, is a series of layers in the human brain consisting partly of gray and partly of white matter, which lies below the anterior part of the thalamus and lentiform nucleus. It is included as part of the anterior perforated substance. It is part of the basal forebrain structures and includes the nucleus basalis. A portion of the substantia innominata, below the globus pallidus is considered as part of the extended amygdala.

<span class="mw-page-title-main">Primate basal ganglia</span>

The basal ganglia form a major brain system in all vertebrates, but in primates there are special differentiating features. The basal ganglia include the striatum, globus pallidus, substantia nigra and subthalamic nucleus. In primates the pallidus is divided into an external and internal globus pallidus, the external globus pallidus is present in other mammals but not the internal globus pallidus. Also in primates, the dorsal striatum is divided by a large nerve tract called the internal capsule into two masses named the caudate nucleus and the putamen. These differences contribute to a complex circuitry of connections between the striatum and cortex that is specific to primates, reflecting different functions in primate cortical areas.

<span class="mw-page-title-main">Medium spiny neuron</span> Type of GABAergic neuron in the striatum

Medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), are a special type of inhibitory GABAergic neuron representing approximately 90% of neurons within the human striatum, a basal ganglia structure. Medium spiny neurons have two primary phenotypes : D1-type MSNs of the direct pathway and D2-type MSNs of the indirect pathway. Most striatal MSNs contain only D1-type or D2-type dopamine receptors, but a subpopulation of MSNs exhibit both phenotypes.

The isothalamus is a division used by some researchers in describing the thalamus.

The Allothalamus is a division used by some researchers in describing the thalamus.

<span class="mw-page-title-main">Ventral lateral nucleus</span>

The ventral lateral nucleus (VL) is a nucleus in the ventral nuclear group of the thalamus.

<span class="mw-page-title-main">External globus pallidus</span> Part of the globus pallidus

The external globus pallidus combines with the internal globus pallidus (GPi) to form the globus pallidus, an anatomical subset of the basal ganglia. Globus pallidus means "pale globe" in Latin, indicating its appearance. The external globus pallidus is the segment of the globus pallidus that is relatively further (lateral) from the midline of the brain.

<span class="mw-page-title-main">Internal globus pallidus</span>

The internal globus pallidus is one of the two subcortical nuclei that provides inhibitory output in the basal ganglia, the other being the substantia nigra pars reticulata. Together with the external globus pallidus (GPe), it makes up one of the two segments of the globus pallidus, a structure that can decay with certain neurodegenerative disorders and is a target for medical and neurosurgical therapies. The GPi, along with the substantia nigra pars reticulata, comprise the primary output of the basal ganglia, with its outgoing GABAergic neurons having an inhibitory function in the thalamus, the centromedian complex and the pedunculopontine complex.

<span class="mw-page-title-main">Blocq's disease</span> Loss of memory of specialized movements causing the inability to maintain an upright posture

Blocq's disease was first considered by Paul Blocq (1860–1896), who described this phenomenon as the loss of memory of specialized movements causing the inability to maintain an upright posture, despite normal function of the legs in the bed. The patient is able to stand up, but as soon as the feet are on the ground, the patient cannot hold himself upright nor walk; however when lying down, the subject conserved the integrity of muscular force and the precision of movements of the lower limbs. The motivation of this study came when a fellow student Georges Marinesco (1864) and Paul published a case of parkinsonian tremor (1893) due to a tumor located in the substantia nigra.

The ventral pallidum (VP) is a structure within the basal ganglia of the brain. It is an output nucleus whose fibres project to thalamic nuclei, such as the ventral anterior nucleus, the ventral lateral nucleus, and the medial dorsal nucleus. The VP is a core component of the reward system which forms part of the limbic loop of the basal ganglia, a pathway involved in the regulation of motivational salience, behavior, and emotions. It is involved in addiction.

References

  1. ↑ Reiner, Anton; Perkel, David J.; Bruce, Laura L.; Butler, Ann B.; Csillag, András; Kuenzel, Wayne; Medina, Loreta; Paxinos, George; Shimizu, Toru; Striedter, Georg; Wild, Martin; Ball, Gregory F.; Durand, Sarah; Gütürkün, Onur; Lee, Diane W.; Mello, Claudio V.; Powers, Alice; White, Stephanie A.; Hough, Gerald; Kubikova, Lubica; Smulders, Tom V.; Wada, Kazuhiro; Dugas-Ford, Jennifer; Husband, Scott; Yamamoto, Keiko; Yu, Jing; Siang, Connie; Jarvis, Erich D. (2004). "Revised Nomenclature for Avian Telencephalon and Some Related Brainstem Nuclei". The Journal of Comparative Neurology. 473 (3): 377–414. doi:10.1002/cne.20118. PMC   2518311 . PMID   15116397.
  2. ↑ Schünke, Michael; Ross, Lawrence M.; Schulte, Erik; Lamperti, Edward D.; Schumacher, Udo (2007). Theme atlas of anatomy: head and neuroanathomy. Thieme. ISBN   9781588904416.
  3. ↑ Yelnik, J., Percheron, G., and François, C. (1984) A Golgi analysis of the primate globus pallidus. II- Quantitative morphology and spatial orientation of dendritic arborisations. J. Comp. Neurol. 227:200–213
  4. ↑ Percheron, G., Yelnik, J. and François. C. (1984) A Golgi analysis of the primate globus pallidus. III-Spatial organization of the striato-pallidal complex. J. Comp. Neurol. 227: 214–227
  5. 1 2 Fox, C.A., Andrade, A.N. Du Qui, I.J., Rafols, J.A. (1974) The primate globus pallidus. A Golgi and electron microscopic study. J. Hirnforsch. 15: 75–93
  6. 1 2 di Figlia, M., Pasik, P., Pasik, T. (1982) A Golgi and ultrastructural study of the monkey globus pallidus. J. Comp. Neurol. 212: 53–75
  7. ↑ Ide, S; Kakeda, S; Yoneda, T; et al. (10 October 2017). "Internal Structures of the Globus Pallidus in Patients with Parkinson's Disease: Evaluation with Phase Difference-enhanced Imaging". Magnetic Resonance in Medical Sciences. 16 (4): 304–310. doi:10.2463/mrms.mp.2015-0091. PMC   5743521 . PMID   28003623.
  8. ↑ Gillies, M. J., Hyam, J. A., Weiss, A. R., Antoniades, C. A., Bogacz, R., Fitzgerald, J. J., … Green, A. L. (2017). The Cognitive Role of the Globus Pallidus interna; Insights from Disease States. Experimental Brain Research, 235(5), 1455–1465. https://doi.org/10.1007/s00221-017-4905-8>
  9. ↑ Surmeier, D.J., Mercer, J.N. and Savio Chan, C. (2005) Autonomous pacemakers in the basal ganglia: who needs excitatory synapses anyway? Cur. Opin.Neurobiol. 15:312–318.
  10. ↑ de Oliveira, AM; Paulino, MV; Vieira, APF; McKinney, AM; da Rocha, AJ; Dos Santos, GT; Leite, CDC; Godoy, LFS; Lucato, LT (October 2019). "Imaging Patterns of Toxic and Metabolic Brain Disorders". RadioGraphics. 39 (6): 1672–1695. doi:10.1148/rg.2019190016. PMID   31589567.
  11. ↑ McCartney, L. K., Bau K., Stewart K., Botha B., Morrow A., (2016), Pallidotomy as a treatment option for a complex patient with severe dystonia, Dev. Med. Child Neurol. 2016 58: (68–69) http://onlinelibrary.wiley.com/doi/10.1111/dmcn.13070/epdf
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