Subthalamic nucleus dynamics track microlesion effect in Parkinson's disease

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurology

Background:

• Parkinson's Disease (PD) motor symptoms temporarily improve post-surgery (microlesion effect).
• Electrophysiological changes during the microlesion effect (MLE) in PD are not well understood.
• Subthalamic nucleus (STN) local field potentials (LFPs) are key to understanding PD.

Purpose of the Study:

• To investigate STN-LFP signal characteristics during the hyperacute (≤2 days) and 1-month post-implantation periods in PD patients.
• To differentiate periodic and aperiodic components of neuronal power spectra during MLE.
• To assess the impact of medication (levodopa) on these electrophysiological parameters.

Main Methods:

• Observational study of 15 PD patients undergoing electrode implantation.
• Simultaneous bilateral STN-LFP recordings using wireless sensing technology.
• Analysis of LFP signals in both medication-on and medication-off states at hyperacute and 1-month post-implantation intervals.
• Neuronal power spectrum parameterization to separate periodic and aperiodic signal components.

Main Results:

• Beta power significantly increased 1 month post-implantation in the off-medication state, compared to the hyperacute period.
• Levodopa administration effectively reduced this elevated beta power.
• Aperiodic signal components (exponents and offsets) decreased at 1 month post-implantation.
• Levodopa modulated aperiodic parameters, returning them to hyperacute levels.

Conclusions:

• Both periodic (beta power) and aperiodic LFP components reflect distinct electrophysiological changes during the MLE in PD.
• Understanding these periodic and aperiodic dynamics is crucial for elucidating MLE mechanisms.
• Accurate evaluation of these signal components can help optimize adaptive deep brain stimulation protocols for PD.