الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
THE motor system is the part of the central nervous system that is involved with movement. It consists of the pyramidal and extrapyramidal system. The extrapyramidal motor system consists of motor-modulation systems, particularly the basal ganglia and cerebellum. The main components of the basal ganglia - as defined functionally - are the striatum (caudate nucleus and putamen), the globus pallidus, the substantia nigra, the nucleus accumbens, and the subthalamic nucleus (Fix and Wilkins 2008). The basal ganglia circuitry processes the signals that flow from the cortex, allowing the correct execution of voluntary movements (Stocco, Lebiere et al. 2010). In Parkinson’s disease, the degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc) triggers a cascade of functional changes affecting the whole basal ganglia network. The most relevant alterations affect the output nuclei of the circuit, the medial globus pallidus and substantia nigra pars reticulata, which become hyperactive (Fix and Wilkins 2008; Stocco, Lebiere et al. 2010).