Propofol Decreases Neuronal Population Spiking Activity in the Subthalamic Nucleus of Parkinsonian Patients

TLDR

The implantation of deep‑brain stimulation electrodes in the subthalamic nucleus for Parkinson disease is commonly guided by microelectrode recording of population spike activity. The study aims to determine whether sedative drugs, specifically propofol, interfere with microelectrode recording during subthalamic nucleus DBS surgery. During surgery, 16 patients had 24 electrode trajectories recorded while propofol was infused at 50 µg/kg/min, and the root‑mean‑square of STN activity was measured before, during, and after sedation. Propofol infusion reduced STN neuronal activity by an average of 23.2 % (significant in 18 of 24 trajectories), but activity returned to baseline within about 9 minutes after stopping, indicating that propofol can be safely used until shortly before microelectrode recording.

Abstract

Implantation of deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN) for the treatment of Parkinson disease is often performed using microelectrode recording (MER) of STN population spike activity. The extent to which sedative drugs interfere with MER is unknown. We recorded the population activity of STN neurons during propofol sedation and examined its effect on neuronal activity.The procedure was performed during DBS surgery for Parkinson disease. We administered propofol (50 μg/kg/min) at a constant electrode location in the STN until stable sedation was achieved. We recorded the electrical activity, and calculated its root mean square (RMS) before, during, and after the propofol infusions.The activity of 24 electrode trajectories was recorded in 16 patients. The RMS of STN activity decreased significantly after propofol administration in 18 of the 24 trajectories. The average normalized RMS decreased by 23.2%± 9.1% (mean ± SD) during propofol administration (P < 0.001), and returned to baseline 9.3 ± 4.0 minutes after it was stopped.Propofol administration leads to a significant decrease of STN neuronal activity. Thus, it may interfere with MER identification of the STN borders. However, activity returns to baseline shortly after administration stops. Therefore, propofol can be safely used until shortly before MER for DBS.