Essay on Parkinson Disease (PD)

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Parkinson disease (PD) is a progressive neurodegenerative disorder characterized mainly by physical and psychological disabilities. This disorder was named after James Parkinson, an English physician who first described it as shaking palsy in 1817 (Goetz, Factr, and Weiner, 2002). Jean- Martin Charcot, who was a French neurologist, then progressed and further refined the description of the disease and identified other clinical features of PD (Goetz, Factr, and Weiner, 2002). PD involves the loss of cells that produce the neurotransmitter dopamine in a part of the brain stem called the substansia nigra, which results in several signs and symptoms (Byrd, Marks, and Starr, 2000). It is manifested clinically by tremor,
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Although many theories and hypotheses were raised as to why this happens, there is no solid information supporting the physiological cause of this, but it is surely one of various factors that may lead to the development of PD.

Neuroanatomy of the Basal Ganglia It has been known that PD is a disorder affecting the basal ganglia. The term basal ganglia is generally applied to a collection of nuclei situated deep within the cerebral hemispheres, lying laterally to the thalamus (Gazzeniga, George, and Mangun, 2008). The basal ganglia are important subcortical structures. They are composed of five nuclei: caudate, putamen, globus pallidus, subthalamic nucleus, and substantia nigra. These nuclei are not thought of a single anatomical entity; rather, they form a functional unity whose contribution is greatly to motor control. Interestingly, this system does not influence movement through spinal cord pathways, but rather acts as part of a feedback loop to all areas of the cerebral cortex, with primary input into motor areas (Aird, 2000). A number of excitatory and inhibitory neurotransmitters are what control this whole process, and a balance of both is required to ensure that smooth, purposeful movement takes place. In order to understand the pathways of which the basal ganglia take part in, it is essential to know the input and output connections of the basal ganglia. The input
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