Movement-related aperiodic activity of subthalamic nucleus in Parkinson’s disease

This study explores the movement-related dynamics of the aperiodic component in subthalamic nucleus (STN) local field potentials (LFPs) in Parkinson’s disease. Eight patients underwent STN LFP and electromyographic recordings during a postoperative period following deep brain stimulation electrode implantation. Recordings were conducted in both OFF- and ON-medication states as patients performed cued hand movements. Time–frequency analysis and extraction of the aperiodic exponent were performed using Morlet wavelets and the FOOOF algorithm, respectively. In the OFF state, pronounced modulation of periodic activity was observed in the 10–20 Hz range during movement, while changes in the aperiodic exponent were subtle and transient. In contrast, in the ON state, periodic activity changes were less prominent, but the aperiodic exponent showed a significant increase before and during movement execution. The exponent was consistently higher in the ON state compared to the OFF state across the movement-locked time window. These findings suggest that the aperiodic exponent may serve as a dynamic marker of excitation–inhibition balance and prokinetic neural states in Parkinson’s disease, offering complementary insights to traditional spectral analyses.