Abstract
Background Electrically evoked compound action potentials (ECAPs) generated in the subthalamic nucleus (STN) contain features that may be useful for titrating deep brain stimulation (DBS) therapy for Parkinson’s disease. While previous studies have leveraged macroscale DBS electrodes, directional DBS leads with split-band contacts are thought to enable sampling ECAPs at a higher spatial resolution both within and adjacent to the STN.
Objective In this study, we investigated the spatiotemporal features of ECAPs in and around the STN across parameter sweeps of stimulation current amplitude, pulse width, and electrode configuration.
Methods Four non-human primates were implanted unilaterally with either a directional (n=3) or non-directional (n=1) DBS lead targeting the sensorimotor STN. Resting-state ECAPs were recorded before and after rendering the subjects parkinsonian with MPTP treatments.
Results ECAP responses were characterized by primary features (within 1.6ms after a stimulus pulse) and secondary features (between 1.6-7.4ms after a stimulus pulse). Using these ECAP features, a linear classifier was able to differentiate electrodes within and dorsal to the STN in all four subjects.
Conclusion ECAP responses varied systematically with recording and stimulating electrode location, which may provide utility in efficiently defining DBS electrode configurations to target pathways in and around the STN for treating symptoms of Parkinson’s disease.
Competing Interest Statement
The authors have declared no competing interest.