Analysis Of Discharge Characteristics And β Oscillation Of Basal Ganglion Model With Time Delay

Parkinson’s disease（PD）is a serious neurodegenerative disease on the spectrum of basal ganglia disease.Its clinical manifestations include difficulty in motor initiation,muscle rigidity and resting tremor.Deep Brain Stimulation（DBS）is a safe and effective clinical treatment for PD today,but its action mechanism is unknown,which hinders the extension and development of DBS.In this thesis,C and MATLAB are used to simulate the basal ganglia network model numerically,analyze the pathogenesis of Parkinson’s disease and the action mechanism of DBS,and find the best DBS parameters under different conditions,so as to provide a certain theoretical basis for clinical treatment.Firstly,the basal ganglia network model consists of four neural nuclei.The discharge characteristics of each neuron in the basal ganglia network model are studied.It is found that four neurons will produce corresponding peak discharges under depolarization input.Hyperpolarized input inactivates four neurons.By changing the synaptic input I_app in neurons,the health status and Parkinson’s state of basal ganglia are simulated.The time course diagram,ISI distribution diagram and power spectrum diagram of the two states are compared and analyzed.It is concluded that the possible pathogenesis of Parkinson’s disease is that the change of synaptic input in the basal ganglia causes the abnormal increase of beta oscillation,which makes the neurons show abnormal discharge behavior,and further makes the thalamus neurons lose their normal relay ability.Secondly,the action mechanism of different target combinations of DBS is analyzed by time history diagram,ISI distribution diagram and power spectrum diagram.Under the action of high-frequency electrical stimulation,the basal ganglia network changes the discharge behavior of GPi neurons through the interaction between nuclei and eliminates the wrong discharge of TH neuron caused by an excessive cluster discharge interval,thus achieving the purpose of treating Parkinson’s disease.In addition,the pulse length is fixed,and the error index contour map of different target combinations is obtain with the stimulation intensity and stimulation frequency as the change parameters to analyze the optimal stimulation parameter selection of different target combinations.Compared with single-target electrical stimulation,three-target electrical stimulation is more stable in the low-error region and has better stability in the low-frequency and low-intensity regions.Compared with the three-target electrical stimulation,the low error regions of GPe-GPi-DBS are almost the same.Finally,this thesis adds time delay to the basal ganglia network model and uses stimulation intensity and stimulation frequency as change parameters to obtain the error index contour map of different target combinations under different time delay conditions,so as to analyze the influence of time delay on the basal ganglia network model and the optimal parameter selection of different target combinations under different time delay conditions.It is found that GPe-DBS can maintain a certain low error region under high time delay conditions.Appropriate time delay will improve the therapeutic effect of GPe-GPi-DBS,but at high time delay,only STN-GPe-DBS in the multi-target combination can maintain a relatively low error level in a specific parameter region.Compared with other target combinations,GPe-DBS is still the best target selection.The results of this thesis can provide theoretical guidance for the study of the pathogenesis of PD and can also provide some reference for the selection of DBS parameters for clinical treatment of Parkinson’s disease.