Multiple stimulation parameters influence efficacy of deep brain stimulation in parkinsonian mice

Deep brain stimulation (DBS) is used to treat multiple neuropsychiatric disorders, including Parkinson's Disease (PD). Despite widespread clinical use, its therapeutic mechanisms are unknown. Here, we developed a mouse model of subthalamic nucleus (STN) DBS for PD, to permit investigation using cell type-specific tools available in mice. We found that electrical STN DBS relieved bradykinesia, as measured by movement velocity. In addition, our model recapitulated several hallmarks of human STN DBS, including rapid onset and offset, frequency dependence, dyskinesia at higher stimulation intensity, and associations between electrode location, therapeutic benefit, and side effects. We used this model to assess whether high frequency stimulation is necessary for effective STN DBS, or if low frequency stimulation can be effective when paired with compensatory adjustments in other parameters. We found that low frequency stimulation, paired with greater pulse width and amplitude, relieved bradykinesia. Moreover, a composite metric incorporating pulse width, amplitude, and frequency predicted therapeutic efficacy better than frequency alone. We found a similar relationship between this composite metric and movement speed in a retrospective analysis of human data, suggesting correlations observed in the mouse model may extend to human patients. Together, these data establish a mouse model for elucidating mechanisms of DBS.