A Shortage of Dopamine
Parkinson's disease occurs when nerve cells, or neurons, in an area of the brain that controls movement become impaired and/or die. Normally, these neurons produce an important brain chemical known as dopamine, but when the neurons die or become impaired, they produce less dopamine. This shortage of dopamine causes the movement problems of people with Parkinson's.
Dopamine is a chemical messenger, or neurotransmitter. Dopamine is responsible for transmitting signals between the substantia nigra and multiple brain regions. The connection between the substantia nigra and the corpus striatum is critical to produce smooth, purposeful movement. Loss of dopamine in this circuit results in abnormal nerve-firing patterns within the brain that cause impaired movement.
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