Substance nigra Substance nigra. A large mass of gray matter between the midbrain tegmentum and the peduncle is the substantia nigra, which is found throughout the length of the midbrain. The nigrostriatal cells are rich in melanin and are the main nuclei for dopamine synthesis in the brain. The substantia nigra is primarily associated with the neostriatum (caudate nucleus and shell) of the telencephalon by round-trip fibers. The nigrostriatal cells are degenerated for some reason and dopamine synthesis is reduced, which is the main cause of tremor palsy (Parkinson’s disease). Under normal physiological conditions, the substantia nigra is an important center for the regulation of movement. The substantia nigra is the largest nucleus in the midbrain and is located on the dorsal aspect of the midbrain peduncle, running the full length of the midbrain and extending upward to the caudal part of the mesencephalon. The substantia nigra is the most developed nucleus in the human brain and is the largest nucleus in the midbrain. The substantia nigra is hemizygous in cross-section and is histologically divided into two parts, the dense dorsal zone and the ventral reticular zone. The dense zone is mainly composed of multi-columnar cells or conical cells, which are rich in melanin granules, giving the dense zone a dark arc-shaped strip in the cross-sectional view, located in the peduncles of both sides of the brain. The dense band is ventral to the most caudal part of the midbrain and is covered by the pontine nucleus. The reticular zone is located immediately below the base of the cerebral peduncle and is wide and composed of scattered irregular cells. The reticular zone cells are iron-rich but not melanin-rich and appear light red in fresh specimens. The reticular zone itself extends upward to the mesencephalon, on the ventral side of the basal thalamic nucleus. Basal nucleus Basal nucleus. (English: Basal ganglia, sometimes directly translated as basal ganglia), is a functional whole composed of a series of nuclei in the deep part of the brain. It is connected to the cerebral cortex, thalamus and brainstem. Its main function is known to be the control of voluntary movements. It is also involved in higher cognitive functions such as memory, emotion and reward learning. Lesions of the nucleus basalis can lead to a variety of motor and cognitive disorders, including Parkinson’s disease and Huntington’s disease. Dopamine. dopamine The product of the action of the enzyme dopamine decarboxylase on dopa, which later forms substances associated with the tanning of epidermal proteins. Dopamine (C6H3(OH)2-CH2-CH2-NH2) is secreted by the brain and can affect a person’s mood. Its official chemical name is 4-(2-ethylamino)benzene-1,2-diol, or “DA” for short. Arvid Carlsson’s identification of dopamine’s role as a messenger in the brain won him the 2000 Nobel Prize in Medicine. Dopamine is a neurotransmitter, a chemical used to help cells transmit impulses. This intracerebral secretion is primarily responsible for the brain’s eroticism, sensations, and the transmission of euphoric and happy messages, and has also been linked to addiction. Pallidum The pallidum. It is an important part of the nucleus basalis located deep in both hemispheres of the brain. The basal nucleus consists of the caudate nucleus, the pallidum, and the shell. Of these, the pallidum and the shell are also collectively referred to as the pulsatile nucleus. Thalamus The thalamus. It is the largest ovoid gray matter nucleus in the mesencephalon and is located on either side of the third ventricle, with the left and right thalamus connected by a gray matter mass (called the middle block). The thalamus is the central organ that produces consciousness, and the function of the thalamus is to synthesize and issue thalamic sensations. Striatum The striatum. The main component of the basal ganglia, including the nucleus accumbens and the caudate nucleus. The nucleus accumbens and the caudate nucleus are interconnected by a large number of striated cell bridges, hence the name striatum. The new striatum refers to the shell and caudate nucleus of the nucleus accumbens, while the old striatum refers to the pallidum. The striatum is a structure of the extra-pyramidal system and is related to the activity of skeletal muscles. Ataxia Ataxia. It is caused by many etiologies in various parts of the nervous system. Any simple movement must involve four groups of muscles: active, antagonistic, synergistic and fixed muscles to be completed and depends on the coordination and balance of the nervous system. There are many etiologies of ataxia, and it is important to first determine which nature it belongs to, and then consider the multiple etiologies involved. Thus, ataxia can occur with damage to the deep sensory, vestibular system, cerebellum and brain, called sensory, vestibular, cerebellar and cerebral ataxias, respectively, as well as factors of unknown origin, some of which are accompanied by mental incompetence or dementia. Chorea Chorea. Also known as rheumatic chorea. It often occurs after streptococcal infection and is a neurological symptom in acute rheumatic fever. The lesions mainly affect the cerebral cortex, basal ganglia and cerebellum and are caused by extrapyramidal dysfunction. The clinical features are mainly involuntary choreiform movements. It is most common in children and adolescents, especially in females aged 5 to 15 years. The incidence decreases rapidly after young adulthood and occasionally occurs in adult women, mainly pregnant women. Encephalitis, diphtheria, chickenpox, measles, whooping cough and other infections, as well as systemic lupus erythematosus and carbon monoxide poisoning may occasionally cause this disease.