The influence of medication on the oscillatory and dynamic characteristics of subthalamic lacal field potentials in Parkinson´s disease

The dysfunction of subthalamic nucleus is the core to Parkinson´s disease. Local field potentials in human subthalamic nucleus contain rich physiological information. The study aimed to quantify the oscillatory and dynamic characteristics of local field potentials of subthalamic nucleus, and their modulation by the medication therapy for Parkinson´s disease. The subthalamic nucleus local field potentials were recorded from 17 patients with Parkinson´s disease at the states of on and off medication. The oscillatory features were characteristic with the power spectral analysis. Furthermore, the dynamic features were characteristic with time-frequency analysis and the coefficient of variation measure of the time-variant power at each frequency. There was a dominant peak at low beta band (13-19 Hz) with medication off. The medication significantly suppressed the low beta component and increased the theta component (4-6 Hz) (P<;0.001, P<;0.001, t-test). The beta component fluctuated in amplitude and the fluctuation was measured by the coefficient of variation. The coefficient of variation in high beta (22-30Hz) was reduced by medication while it was increased in high gamma band (65-77 Hz). Medication has significant modulation to subthalamic nucleus neural oscillatory synchronization and dynamic features. The subthalamic nucleus neural activities tend towards stable state under medication. The findings would provide quantitative biomarkers for studying the mechanisms of Parkinson´s disease and clinical treatments of medication or deep brain stimulation.