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  1. Dec 29, 2021 · Parkinson’s is caused by the loss of neurons (nerve cells) in the substantia nigra, a region of the midbrain. Neurons in this region that release the signaling molecule dopamine are primarily affected, leading to the disease’s characteristic symptoms.

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    • What Is The Substantia Nigra?
    • Its Duties?
    • Related Disorders

    The black substance part of the basal ganglia, a cerebral system composed of the neoestriate, the pale globe and the subthalamic nucleus, as well as the substantia nigra. It is located in the part of the brain known as "mesencephalon." This region is considered part of the brain stem and is related to movement, consciousness, alertness, vision and hearing. In the human brain we find black substance on both sides of the midline. That is, there is a black substance in each hemisphere of the brain. Neuromelanin, a pigment of dopaminergic neurons(abundant in this region), gives its name to the black substance as it gives it its characteristic dark tone. 1. Related article: "Basal ganglia: anatomy and functions"

    Most of the functions in which the substantia nigra is involved have to do with its compact part and with dopamine. However, the reticulated part also influences other processes, especially neuronal inhibition (through GABA) and ocular movements.

    Parkinson's disease is due to the degeneration of the dopaminergic neurons of the compact part of the substantia nigra. In fact, the discoloration of the substantia nigra that occurs in this disorderit is due to the reduction in the density of this type of neurons, which contain neuromelanin. Many of the characteristic symptoms of Parkinson's are related to a deficit in the functions of the substantia nigra: tremors of rest, slowness of movement, rigidity, low mood, sleep disturbances, etc. The abnormal activation of the neurons of the substantia nigra has been related both to the symptoms of Parkinson's disease and to the appearance of epileptic seizures. Dopamine and the substantia nigra they are also involved in schizophrenia. The dopaminergic pathways are altered in this disorder, and dopamine levels are usually very high. Likewise, schizophrenia produces structural changes in the substantia nigra. 1. You may be interested: "The 6 types of schizophrenia and associated characteri...

  3. Jan 11, 2022 · Substantia nigra is a part of midbrain , the top most structure present in the brain stem. It is present in the anterior part of midbrain in the cerebellar peduncles. Substantia nigra divides the cerebellar peduncles into anterior crus cerebri and posterior tegmentum of mid brain.

  4. Dec 21, 2021 · The substantia nigra is a semilunar lamina of heavily pigmented neurons located between the crus cerebri and the mesencephalic tegmentum. The distinguishable dark color comes from the pigment neuromelanin. The substantia nigra spans all the levels of the midbrain, from the pons to the subthalamus.

    • What Is The Nigrostriatal Pathway?
    • Related Structures
    • Role in Brain Functioning
    • Clinical Implications and Associated Disorders

    The nigrostriatal pathway is one of the four pathways that make up the dopaminergic system. Together with the mesolimbic pathway, the mesocortical pathway and the tuberoinfundibular pathway, it is responsible for transporting dopamine from one place to another in the brain. To be more precise, the nigrostriatal pathway is one whose beams project from the substantia nigra to the striatum, specifically the caudate nucleus and the putamen. This way has a fundamental role in motor control, being the stimulation of the intentional movement the main function of this. Injuries or alterations typical of disorders such as Parkinson's disease or chorea, affect the nigrostriatal path generating numerous symptoms. Likewise, D2 dopamine antagonists can induce extrapyramidal symptoms associated with pseudoparkinsonism.

    As mentioned above, the nigrostriatal pathway runs through the brain from the substantia nigra to the caudate nucleus and putamen, located in the striatum.

    As we have seen, the nigrostriatal pathway, and those structures that make it up, are responsible for govern and favor the control of voluntary movements. In general, the control of movements is the result of the satisfactory combination of sensitive information and motor information coordinated by the central nervous system (CNS). Within this motor control we find voluntary movements, involuntary movements and reflexes. However, in this case, voluntary movements are controlled by the nigrostriatal route. Voluntary movements are carried out with the intention of achieving an objective, that is, they are proactive. Further, most of these movements can be learnedand improved through practice

    Knowing the structures related to the mesocortical pathway and the functions it performs, it will be much easier to understand what effects or consequences the decrease in activity in these neural networks leads to. This decrease in the level of activity can occur either by the administration of dopamine D2 antagonist drugs or by progressive degenerationof the pathway, which gives rise to diseases such as choreas or Parkinson's disease.

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