Anatomy-Lexicon

Basal ganglia

Synonyms

Master ganglia, basal nuclei

introduction

The term “basal ganglia” refers to the core areas below the cerebral cortex (subcortical), which are primarily responsible for controlling functional aspects of motor skills. In addition, the basal ganglia control cognitive signals and are involved in processing information from the limbic system.
From a neuroanatomical point of view, the basal ganglia form an essential part of the so-called extrapyrimidal motor system (in short: EPMS).

anatomy

The basal ganglia settle within the two hemispheres of the brain from different structures together that carry out a lively exchange of information among each other. From an anatomical point of view, the basal ganglia are formed from the following parts:

Caudate nucleus (curly core)
Nucleus lentiformis (lenticular core) which in turn is divided into:
- Putamen (Shell body)
- Pallidum (Globus pallidus)

They are also considered functionally black substance (Substantia nigra) of the midbrain and the Subthalamic nucleus counted to the basal ganglia.

During the early development of the embryo, the putamen and the caudate nucleus are in close proximity. However, as the central nervous system matures, these two structures become through training long projection tracks (so-called Internal capsule) separated from each other.
In the adult brain, only a fine strip connects the name "Striatum“Wears the putamen with the curly core.
The Striatum represents the only one at the same time Entrance station in the basal ganglia system. External impulses are thus transmitted to the individual structures of the basal ganglia via the fine fiber strand.
information primarily preserve the basal ganglia from the cerebral cortex and the gray matter. In addition, various core areas of the central nervous system (for example the so-called Raphe Kernels and the Formatio reticularis) regular impulses to the basal ganglia.

Outgoing information are from the basal ganglia via the pallidum internum (in short: GPI) sent to other brain regions. About the inhibiting Neurotransmitters GABA project the basal ganglia directly onto the Thalamus.

function

Overall, the human brain has so far been considered less well understood.
Because of this, the complex ones too Functions of the basal ganglia til today little researched.

It is assumed that the individual structures of the basal ganglia significantly contribute to the selection and Processing of motor and non-motor behavior patterns involved.
In addition, they regulate the oppression from current activation patterns that are not required.
In the course of these complex tasks, however, the basal ganglia work not independent. Rather, the caudate nucleus, the putamen and the globus pallidus are integrated as filter stations Control loop involved.
The flow of information emanates from the cerebral cortex, is conducted via the basal ganglia to the thalamus and from there transferred to the frontal lobe of the cerebral cortex.
Almost every part of the cerebral cortex sends information to the entrance station of the basal ganglia (i.e. to the Striatum). The only exceptions are the primary visual cortex (Visual center) and those for that Listen responsible brain areas.
Via the starting stations of the basal ganglia (Substantia nigra and Globus pallidus) are processed in cores End information about inhibiting impulses to the thalamus sent. This in turn sends activating impulses to the cerebral cortex of the frontal lobe.

Diseases originating in the basal ganglia

Functional disorders in the area of the basal ganglia can be far-reaching consequences For motor and non-motor processes of the body. For this reason, the diseases triggered by disorders of the basal ganglia often show themselves clinically as pronounced symptoms.
The most well-known diseases associated with the basal ganglia include:

Parkinson's Syndromes like Parkinson's disease
Dystonia Syndromes (Diseases with pronounced movement disorders)
Choreatic Syndromes like Chorea huntington
Attention Deficit / Hyperactivity Disorder (ADHD)
Tic disorders like that Tourette syndrome

Parkinson's disease

Parkinson's disease (synonyms: Parkinson's disease, shaking sickness) is one of the most well-known diseases associated with functional disorders of the basal ganglia.
This disease is a creeping one neurodegenerative process.
The cause of the development of Parkinson's disease is Dopamine-producing nerve cells are destroyed in the so-called gray matter (Substantia nigra).
Immediate consequence is a defect of the messenger substance Dopamine and an accompanying one Reduction of the activating influences the basal ganglia to the cerebral cortex.
The most common Symptoms Parkinson's disease are pronounced Muscle stiffness (Rigor) and the Slowing down of motion sequences (Bradykinesia) which over time into a complete immobility (Akinesia) can pass.
In addition, patients suffering from Parkinson's disease often show clear signs Muscle tremors (tremor) and a Postural instability (postural instability) on.
The first symptoms of this basal ganglia-dependent disease usually appear between the ages of 50 and 79 on. Patients before the age of 40 are only affected in rare cases.
The treatment Parkinson's disease is mainly medicated. The direct one Administration of dopamine or dopamine-like substances should be delayed as long as possible. The reason for this is the declining response to common drugs after a period of several years.

For more information, see: Parkinson's disease

Chorea huntington

In the case of the under the name "Huntington's disease" (synonym: Huntington's Disease) known disease is a previously incurable Illness. Huntington's disease is one of the most feared hereditary Diseases of the brain and is one of the basal ganglia-associated diseases.
The affected patients show a progressive one Downfall of the striatum on.
Since this part of the basal ganglia mainly provides information from the area of muscle control and mental functions, those affected show one pronounced symptoms. The first symptoms usually show up between the ages of 30 and 40.
In everyday clinical practice it can be observed that the severity of the disease is closely related to the appearance of the first symptoms. The earlier the disease occurs, the more severe its course. In the early stages, those affected suffer from unwanted, non-suppressible movements (Hyperkinesia) and one in general decreased muscle tone. In the course of time, however, there is an increasing Sedentary lifestyle (Hypokinesia) and a increased muscle tone. Furthermore, most patients suffer from pronounced functional disorders of the movement sequences years before the first appearance of functional disorders mental dysfunction.