Temporal Dynamics of Microlesion Effects in Subthalamic Local Field Potentials

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurology

Background:

• Deep brain stimulation (DBS) is a key treatment for Parkinson's disease (PD).
• Electrode implantation causes a transient 'microlesion effect' that can alter brain activity.
• Understanding the evolution of this microlesion effect is crucial for optimizing DBS.

Purpose of the Study:

• To investigate the temporal evolution of subthalamic local field potentials (LFPs) post-electrode implantation in Parkinson's disease.
• To characterize the changes in periodic and aperiodic LFP components and their spatial distribution.
• To explore potential correlations between LFP changes and clinical outcomes.

Main Methods:

• Analysis of resting-state LFPs from 13 Parkinson's disease patients across six postoperative periods (up to 1 year).
• Decomposition of power spectral density into periodic and aperiodic components.
• Nonparametric within-subject analyses and population-averaged regression for spatial evaluation.

Main Results:

• Total LFP power and aperiodic parameters showed an inverted-U trajectory, peaking at 31-90 days.
• Periodic beta power (13-30 Hz) increased from 1-3 months onward, remaining elevated at 6-12 months.
• Distinct spatial topographies were observed for periodic beta (dorsal sensorimotor) and aperiodic activity (ventral).

Conclusions:

• The microlesion effect dynamically alters LFP characteristics, with a later relative prominence of periodic beta activity.
• Spatial dissociation between periodic and aperiodic LFP features offers insights for biomarker selection and adaptive stimulation targeting in PD.
• While clinical improvements were noted, direct correlations with specific LFP metrics did not withstand rigorous statistical correction.