Optimization of Discharge Pattern in Parkinson Disease Using Particle Swarm Optimization

Abstract

Parkinson disease is a movement disorder which affects basal ganglia nuclei in the brain.Basal ganglia nuclei are responsible for the control of movement of body parts. The actual cause of the origin of Parkinson disease (PD) is not known but depletion of newlinedopamine neurotransmitter is the primary cause. However, cause of dopamine depletion newlineis yet to establish. Various mathematical models based on different ionic currents and newlinemembrane potentials reveal that discharge patterns are affected in this disease. Discharge newlinepatterns evolved from the single conductance based non-linear model are considered to newlinesee the effect of various ionic currents in this thesis. Various parameters affecting the newlinedischarge patterns significantly are ptimized using particle swarm optimization (PSO) newlinealgorithm. These optimum values of the parameters are chosen in such a way that if they are given to the model, the discharge patterns of healthy primate are generated. The same is validated by computing orrelation coefficient between the two discharges patterns newlinewhich is nearly 1 for different nuclei of basal ganglia considered in the thesis. newlineThe first two chapters of the thesis are dedicated to introduction of the topic and literature review of the related research work. In the third chapter, a conductance based model of newlinesubthalamic nucleus is studied and the parameters to which the discharge patterns are most sensitive are optimized using particle swarm optimization algorithm. In chapter four, conductance based model of basal ganglia is presented for internal and external newlineglobus pallidus nuclei. The discharge patterns have been generated and compared with the discharge patterns of a healthy primate for optimized parameters. Chapter five presents the coupled conductance-based model of basal ganglia in which coupling is done newlinebetween subthalamic nucleus and external globus pallidus. Membrane potential of the newlineexternal globus pallidus is given as input to the synaptic current of subthalamic nucleus newlinewhereas membrane potential o