Irregular high frequency patterns decrease the effectiveness of deep brain stimulation in a rat model of Parkinson's disease

Deep brain stimulation (DBS) is an effective treatment of Parkinson's disease, but its mechanisms are still unclear. To test the hypothesis that DBS alleviates motor symptoms by regularizing neuronal firing, we applied regular frequency stimulation between 5-260 Hz as well as irregular high frequency stimulation with an average rate of 130Hz to rats with unilateral 6-hydroxydopamine (6-OHDA) lesions. We found that high frequency regular stimulation above 130Hz was more effective than both low frequency stimulation and high frequency irregular stimulation at normalizing pathological circling behavior. Our results support the hypothesis that DBS is effective because it is able to mask pathological firing patterns within the basal ganglia, and highlight the importance of the temporal pattern in addition to the rate of stimulation.