e cells of the cerebral cortex send instructions to the muscles of the body located in the cortical motor area. These nerves deliver messages to the muscles required to accomplish the desired movement and tells the muscles when and how much to contract. This pathway is possible only when the neurotransmitter dopamine is present to facilitate the process. The brain must know where the body part is located at all times and acquires this information through signals from millions of specialized sensors in joints, tendons, and muscles and must constantly reevaluate this information with movement.
             In patients with Parkinson's disease, this pathway is disrupted. There is a severe lack of the neurotransmitter dopamine in the striatum. The dopamine-producing nerve cells, called the substantia nigra, normally contains much black pigment. These pigment-containing, dopamine-producing cells progressively become depigmented and die. The remaining cells work overtime but eventually cannot meet the needs of the striatum in terms of the amount of dopamine they are able to produce. This therefore causes disturbances in th
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