Abnormal Synchronous Oscillations In Awake Parkinson's Disease Rat Model Under Resting State

Parkinson's disease is also known as paralysis agitans (paralysis agitans, shaking palsy).It is the disease that occurred in substantia nigra and nigrostriatal pathway of middle-aged patients, the main pathological changes is due to DA insufficiency of corpus striatum caused by degeneration of dopaminergic neurons in nigrostriatal pathway and decreased DA biosynthesis in the surviving neurons.Clinical symptoms of Parkinson disease is characterized by bradykinesia, rigidity, resting tremor, postural instability along with non-motoric symptoms like autonomic, cognitive and psychiatric problems.In recent years, the incidence of Parkinson disease showed a rising trend,and 1–2% of the'over 50'population was suffering from this disease with a current estimation of 1.5 million in the US alone.With the aging of our population, the number of PD patients are increasing. However, as the pathogenesis of PD is not clear, especially the current theory can not explain the occurrence of PD tremor,so there is still no ideal treatment for the disease at home and abroad,which is a major problem of functional neurosurgery need to be solved. Through multi-point simultaneous recording of of local field potential of globus pallidus and cortical EEG of awake rat under resting state in our experiment,we tried to explore synchronization and its variation of motor cortex and Globus Pallidus in PD rat,to further undertand the pathogenesis and to explore the mechanism of tremor.Objective To understand characteristics of unusual oscillatory activity of the basal ganglia - cortical loops of Parkinson's disease(PD) in the static awake state.Methods PD models were established by injection of 6-hydroxydopamine (6-OHDA) to 2 points in rats'brains, and the injection of apomorphine that induced rotation was used to evaluate the quality of the model; We applied electrophysiological recording technique of multi-macro electrode in vivo combined with video recording technique to the recording of local field potential of globus pallidus and cortical EEG in freely moving normal rats and PD model rats.Power spectral analysis and coherence analysis was used to reveal the frequency components of recording sites,functional connectivity and synchronization of clusters of neurons in different recording sites.Results The damage of dopamine neurons in mesencephalon caused by 6-OHDA can change the activities of basal ganglia-cortical loops of Parkinson disease rat;Compared with normal rats,the duration of 5-9Hz mu rhythm oscillation of LFP(local field potential) in Globus Pallidus and ECoG significantly extended;The frequency of EEG of motor cortex in PD rat increased;6-OHDA induced an increased synchronization of mu rhythm oscillation in globus pallidus and primary motor cortex;Interregional synchronization between Globus pallidus and primary motor cortex was found by us, and the synchronization of the lesioned side is more obvious than that of opposite side.Conclusion The damage of Mesencephalic dopaminergic neuron by 6-OHDA can induce the duration of mu rhythm of Globus pallidus prolonged,and also change the basal ganglia-cortical loop functional connectivity, causing abnormal and synchronized mu rhythm between the main motor cortex and the globus pallidus. Whether this abnormal mu rhythm activities are related to static tremor of PD or not needs further experiments to study.