Parkinson's disease is a very common neurodegenerative disorder that tends to present late in life. It is a disease with a lifetime incidence of 2.5% and a prevalence of at least 2% in individuals over 65 - 70 years of age. Millions of humans are victims of this neurodegenerative disease . It is caused by a progressive degeneration and loss of nigrostriatal dopamine-containing neurons. Sometimes degeneration also occurs in systems of non-dopaminergic neurons . The common symptoms of Parkinson's disease are tremor, rigidity, and hypokinesia (abnormally decreased mobility). Together with these problems various degrees of cognitive, autonomic, and psychiatric abnormalities may also be present .
The dopaminergic neurons have their cell bodies located in the substantia nigra pars compacta (SNpc). These special neurons send axons to the caudate and putamen which is collectively known as the corpus striatum. The gradual degeneration of these cells initiates a chain of disorders. Degeneration results in the ongoing decrease over time of striatal dopamine levels which is very essential for normal functioning. This in turn produces a decline in striatal output to the thalamus. These alterations result in a decrease in cortical motor output. ...Show more