It is related tocerebral cortex、thalamusandbrainstemto be connected.Its main function is to control autonomous movement.It also participates in advanced cognitive functions such as memory, emotion and reward learning.The lesions of the basal ganglia can lead to a variety of motor and cognitive disorders, including Parkinson's disease and Huntington's disease.The coronal section of the human brain shows the location of the major components of the basal ganglia.Including: caudate nucleus, shell, globus pallidus, hypothalamic nucleus, nucleus accumbens and substantia nigra.[1]
Basal nucleus, also known asBasal gangliaIt is the general name of some nuclei in the medulla of the cerebral hemisphere, which is composed of caudate nucleus, shell, globus pallidus (collectively called striatum), claustrum nucleus and amygdala.The striatum and the substantia nigra of the subthalamic nucleus together constitute a subcortical circuit regulating movement.Cooperate with cerebral cortex and cerebellum to regulate random movement, muscle tension and postural reflex.[3]
appearance
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Basal nucleus
The shape of the basal nucleus The caudate nucleus is arcuate, and the anterior part of the enlargement is the head on the dorsal sidethalamusIn the front of the temporal lobe, the caudate nucleus body is attached to the dorsolateral edge of the dorsal thalamus. The tail is long and thin, curving forward into the temporal lobe, and the end is connected with the amygdala.The shell and globus pallidus are collectively called lenticular nucleus. The lenticular nucleus is wedge-shaped on the horizontal or frontal section. The base of the broad eminence is outward and the tip is inward. It is divided into the medial globus pallidus and the lateral shell by the lateral medullary plate. The globus pallidus is also divided into the medial and lateral globus pallidus by the medial medullary plate.The caudate nucleus and the shell are relatively new in evolution and have similar functional links, so they are collectively called the new striatum. The globus pallidus occurs earlier, called the old striatum.The screen nucleus is a thin layer of gray matter between the insular cortex and the shell. The white matter separated from the shell on the inside is called the outer capsule. The white matter separated from the insular cortex on the outside is called the outermost capsule. The screen nucleus has a fiber connection with the cerebral cortex.The subthalamic nucleus, substantia nigra and red nucleus are closely related to the striatum in functionExtracorporeal system, or included in the concept of basal nucleus[3]。
Information transmission path
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The information transmitted from the motor area of the cerebral cortex passes through the cerebral cortex, basal nucleus and thalamus, and then returns to the motor area of the cerebral cortex, so as to maintain muscle tension, control involuntary muscle movement, and ensure smooth movement with the cerebellum.[4]
structure
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Striatum
Striatum of basal nucleus
The largest nerve nucleus in the basal nucleus, the shell and caudate nucleus are called neostriatum.Although from the perspective of phylogeny, the earlier appearance of pallidum (old striatum) is also considered as part of the striatum, but without explanation, the striatum generally refers to the new striatum.The function of striatum is related to the generation of consciousness such as motor function and happiness.[4]
Lenticular nucleus
The lenticular nucleus is the general name of the globus pallidus and the shell. It is located on the lateral side of the thalamus. It is separated from the thalamus by the internal capsule (axonal fiber bundle from the neocortex and thalamus). It is a conical gray matter that can unconsciously control and regulate the movement and tension of skeletal muscles.Originally, the pale sphere and the shell were integrated, but they were gradually divided into two parts by the inner envelope in the process of biological evolution.[4]
shell
It forms the striatum together with the caudate nucleus, and at the same time, it forms the lenticular nucleus together with the enclosed pallid bulb.[4]
Globus pallidus
The brighter gray matter in the lenticular nucleus can be divided into two parts: the medial part (GPi) and the lateral part (GPe).Both the medial and lateral parts can make GABA play a role, which is related to the realization of motor function.In addition, it is also related to neural processes such as determination of will.[4]
Caudate nucleus
It is located around the lateral ventricle in the shape of a knife.The head end is an expanded nuclear head, while the nuclear body and tail are thin, which are related to learning and memory functions.[4]
Hypothalamic nucleus
Be able to adjust the movement slightly during movement.When inhibited by the lateral part of globus pallidus, it can transmit excitatory stimulation to the lateral part of globus pallidus, the medial part of globus pallidus, and the reticular part of substantia nigra.[4]
Substantia nigra
Located in the midbrain, it is black due to the high content of melanin, and can regulate the movement and tension of striated muscles, which can be roughly divided into two parts: the compact part and the reticular part.The compact part can release dopamine to the striatum and inhibit excitation;The reticular part can inhibit the thalamus by receiving GABA stimulation from the striatum and the medial part of the globus pallidus, as well as excitatory glutamate stimulation from the hypothalamic nucleus.[4]
Fibre connection
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The caudate nucleus and lenticular nucleus in the basal nucleus are collectively called striatum.The caudate nucleus and shell occur late in the germline, so they are collectively called neostriatum.The globus pallidus occurs earlier and is an older part, called the old striatum.The fibers entering the neostriatum mainly come from the fifth layer cells of the cortex, the central middle nucleus of the thalamus (a small part from the plate nucleus), the compact part of the substantia nigra, the raphe nucleus of the brain stem and the locus coeruleusNoradrenergic neuronsThe main efferent fibers end in the globus pallidus and the reticular part of substantia nigra, where the substantia nigra fibers rent substantia nigra striatum fibers to form the striatum substantia nigra striatum loop, which plays a feedback regulation role on substantia nigra dopaminergic neurons.The transmitting fibers of the globus pallidus mainly come from the caudate nucleus, the shell, and the subthalamic nucleus. The main efferent fibers end in the thalamus, the pedopontine reticular nucleus at the tail end of the midbrain tegmentum, the subthalamic nucleus, and the substantia nigra compacta. The subthalamic fibers and the subthalamic globus pallidus fibers of the subthalamic constitute the globus pallidus subthalamic nucleus globus pallidus round-trip circuit, which is collectively called the subthalamic tract.The fiber connection of the nucleus platensis is not clear to people, but animal experiments show that it has a fiber connection with the cerebral cortex.The fiber connection of human amygdala is not very clear.[5]
Arterial supply
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Middle cerebral arteryAnd the central branches from the anterior cerebral artery pass through the anterior perforating substance into the basal nucleus and supply it,Anterior choroid plexus arteryAnd the posterior choroid plexus artery also send branches to supply the caudate nucleus, andPosterior cerebral arteryThe thalamic striatal artery branches out to supply the lenticular nucleus.[5]
function
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Nigrostriatal system thalamic pathway
In higher mammals, although the function of the striatum is still closely related to movement, it is no longer independent, but closely related to the motor cortex, subthalamic nucleus, substantia nigra and even cerebellum. It has retreated to be a secondary motor center under the control of the neocortex of the brain, becoming an important structure under the cortex of the extrapyramidal system, playing an important role in the regulation of body movement, such as the regulation of muscle tension,The stability of random movement and the coordination of muscle movement.The amygdala is the subcortical center of the limbic system, which is related to emotion, behavior, visceral activities and autonomic nervous function.[5]
Localization of basal nucleus damage
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The basal nuclei includeCaudate nucleus、Lenticular nucleusAnd subthalamic nucleus are important components of extrapyramidal system.The clinical manifestations of basal nucleus damage are as follows.[6]
Hypertonic and hypokinetic syndrome
The pathological changes mainly involve pallidum and substantia nigra. The clinical manifestation is increased muscle tension. When the current arm extends or flexes, it shows intermittent gear sign.The tremor is relatively slow but rhythmic, which is mostly seen at the distal end of the limbs. The fingers, such as rubbing pills or counting money, often occur when the limbs are still;When the limbs do some conscious actions, the tremor will be reduced or disappear.[6]
Hypotonia and hyperkinesia syndrome
The lesions mainly invade the neostriatum and subthalamic nucleus, and the main manifestations are: ①Dance like movement, is an amorphous, sudden, fast dance like involuntary movement. The lesions mainly occur in the putamen, mostly in rheumatism or degenerative diseases. ②Torsion spasticity: when the patient walks, the neck, trunk and proximal end of the limb have spiral torsion movement, and the lesion extensively invades the extrapyramidal system structure, which can be seen after encephalitis andHepatolenticular degenerationEtc. ③The hand foot creeping movement produces intermittent and slow stretching and flexing or separated earthworm like peristalsis for the distal part of the limbs, especially the fingers and toes, and reduces muscle tension.The lesions mainly involve the caudate nucleus, which can be seen in congenital brain development disorder and hepatolenticular degeneration. ④The oblique throwing movement is a large and powerful movement of one side of the body. There is no movement like throwing, kicking or dancing in the trunk and face.The lesions mainly involve the subthalamic nucleus, which can be seen inCerebral arteriosclerosisandIntracranial tumorEtc.[6]
