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Parkinson’s disease (PD) is one of the most prevailing neurodegenerative disorders affecting populations all over the world.  Almost from 4.1 to 4.6 million patients suffering from PD are counted across the  fifteen most crowded countries where  live the two thirds of the world population. The average age of the PD onset is 55. The incidence grows along with the age: from 20/100000 cases in the overall population to 120/100000 in the elder population above 70 years old.   This number is expected to reach 8.7 / 9.3 million in 2030. China is expected to increase from two million to five million by 2030. (E. R. Dorsey, et al.; Neurology 2007) Gender difference  in the rate of incidence of PD was reported in many epidemiological studies:  from 1.5 to 2 times higher in men than in women. In Japan, however, there is a higher incidence in women. Environmental factors are critical in determining the incidence rate of the disease. Some studies repo...

A circuit of evaluation and selection of the alternatives ( see here ) is considered a reliable model in neurobiology. In this published study , valuation and choice of a decisional process during Two-Alternative Forced-Choice ( TAFC ) task are represented as a two-layered network of computational cells, where information accrual and processing progress in nonlinear diffusion dynamics.  The evolution of the response-to-stimulus map is thus modeled by two linked diffusive modules ( 2LDM ) representing the neuronal populations involved in the valuation-and-decision circuit of decision making (Figure 1). Diffusion models are naturally appropriate for describing accumulation of evidence over the time [ see here ] . This allows the computation of the response times (RTs) in valuation and choice, under the hypothesis of ex-Wald distribution. A nonlinear transfer function integrates the activities of the two layers. The input-output map based on the infomax principle makes the 2LD...

The basal ganglia (BG) are a set of subcortical nuclei (Figure 1). They receive cortical and thalamic input mainly through the striatum (i.e., by the putamen and the caudate nucleus) which forms the input layer of BG. Next, the information flows through the globus pallidus to the major output layer, the substantia nigra pars reticulata (SNr). There also exists an internal loop between the globus pallidus and the subthalamic nucleus. The substantia nigra pars compacta (SNc) projects back to the striatum with dopaminergic neurons . The input layer of BG is rich of spiny neurons (SP), which receive huge cortical (C) connections. The SPs also receive afferents from dopaminergic neurons (DA) in SNc which synapse on to the SPs in the striatum. Inhibitory dynamics are also present in the BG. The activity of the SPs inhibits the DA neurons in the SNc. The subthalamic side-loop, on the contrary, disinhibits the DA which can result in the excitation of the DA neurons proportional to the input...