A dynamical-systems model for Parkinson's disease

The juxtaposition of hypokinetic and hyperkinetic symptoms in Parkinson's d isease (PD) presents a challenge in modeling the basal ganglia. We propose a model of the striatum that can account for the mixture of symptoms seen i n PD. In the model, the problem of motor planning is cast in terms of a par ticle in a potential, where potentials are generated internally in striatal modules, subject to afferent control. Planned movement is governed by Hami lton's equations, where potential energy is supplied by potentials expresse d in the striatum. To test the model in realistic situations, a dynamic sim ulation of a two-link robot arm was used. Normal movement is modeled and sh own to exhibit observed experimental properties. Symptoms of PD are reprodu ced by modeling hypothetical consequences of PD pathology.