Duke University Durham, North Carolina, United States
Introduction: Deep brain stimulation (DBS) in the subthalamic region is an established therapy for the treatment of Parkinson’s disease (PD). Computational models of subthalamic DBS are often used to characterize the brain connections that are activated by the stimulation. Evolving hypotheses from these analyses suggest that activation of specific pathways may be related to the control of specific symptoms. In turn, identifying optimal locations for targeted stimulation of specific pathways may prove useful in the treatment of PD.
Methods: The goal of this study was to create detailed DBS axonal pathway activation maps for the subthalamic region across a wide range of stimulation settings (i.e. polarity, pulse width, amplitude) and electrode locations. The subthalamic region was mapped with a grid of 256 DBS locations. We used an anatomically and electrically detailed computational model of subthalamic DBS to calculate responses for nine different axonal pathways of interest at each of the grid locations. An open access interactive software tool is provided for users to analyze the pathway activation results.
Results: Electrode location plays a major role in dictating the assortment of axonal pathways that are activated by subthalamic DBS. We identified electrode locations that biased activation toward the pallidothalamic, motor hyperdirect, or cerebellothalamic pathways, respectively. These pathway-targeted DBS locations were predominantly dorsal to the subthalamic nucleus. Long pulse durations or anodic stimulation tended to push the target points more dorsally.
Conclusion: Subtle differences in stimulation location and/or parameter settings can substantially influence the collection of pathways that are activated during subthalamic DBS.
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