Distinctive neuronal firing patterns in subterritories of the subthalamic nucleus

Objective : Deep brain stimulation of the subthalamic nucleus (STN\u2013DBS) is an established treatment for Parkinson\u2019s disease (PD). Anatomical connectivity analyses and task-related physiological studies have divided the STN into different functional domains: sensorimotor, limbic, and associative \u2013 located in its dorsolateral (dSTN), anteroventral (vSTN) and medial territories, respectively. Targeting sensorimotor STN is essential for stimulation efficacy and is supported by intraoperative micro-electrode recordings. A different neuronal signature in microelectrode recordings across STN subterritories was explored in this study. Methods: Stable recordings from 30 PD patients were assigned to dSTN or vSTN by means of an anatomical method (based on fused computed tomography/magnetic resonance images) and through a priori tri-segmented partition of the recording itself. We computed the inter-spike interval (ISI) and ISI-characteristics, mean firing rate (MFR), discharge patterns and mean burst rate (MBR) of each detected single unit activity. Results: We showed a different MBR between dSTN and vSTN (1.51 \ub1 0.18 vs. 1.76 \ub1 0.22 events/minute, Wilcoxon rank sum test, p < 0.05) and a trend in the difference between their MFR (12.78 vs. 15.05 Hz, Wilcoxon rank sum test, p = 0.053) only with the anatomically based method