Objective. Local field potential (LFP) recordings along a deep brain stimulation (DBS) lead can provide useful feedback for titrating DBS therapy. However, conventional DBS leads with four cylindrical macroelectrodes likely undersample the spatial distribution of sinks and sources in a given brain region. In this study, we investigated the spectral power and spatial feature sizes of LFP activity in non-human primate subthalamic nucleus and globus pallidus using chronically implanted 32-channel directional DBS arrays. Approach. Subthalamic nucleus and globus pallidus LFP signals were recorded from directional DBS arrays in the resting state and during a reach-and-retrieval task in two non-human primates in naïve and parkinsonian conditions. LFP recordings were compared amongst bipolar pairs of electrodes using individual and grouped electrode configurations, with the latter mimicking the cylindrical macroelectrode configurations used in current clinical LFP recordings. Main results. Recordings from these DBS arrays showed that (1) beta oscillations have spatial 'fingerprints' in the subthalamic nucleus and globus pallidus, and (2) that these oscillations were muted when grouping electrode contacts together to create cylindrical macroelectrodes similar in relative dimension to those used clinically. Further, these maps depended on parkinsonian condition and whether the subject was resting or performing a motor task. Significance. Development of future closed-loop DBS therapies that rely on LFP feedback will benefit from implanting DBS arrays with electrode sizes and spacings that are more consistent with the dimensions of oscillatory sinks and sources within the brain.
Bibliographical noteFunding Information:
This work was supported by the Michael J Fox Foundation and the National Institutes of Health (R44-NS060269, R44-NS103714, R01-NS094206, R01-NS037019, and P50-NS098573). We thank Rio Vetter, Jamie Hetke, and KC Kong at NeuroNexus Technologies for help with design and fabrication of the DBS arrays. We also thank Noam Harel, Essa Yacoub, and Gregor Adriany at the Center for Magnetic Resonance Research (P41-EB015894, P30-076408, U54-MH091657) for help with the MRI and CT imaging used in this study. We also thank Filippo Agnesi for technical assistance with the experiments.
- Parkinson's disease
- deep brain stimulation
- globus pallidus
- local field potentials
- microelectrode arrays
- subthalamic nucleus