LAUSR

OBJECTIVE To investigate whether deep brain stimulation (DBS) lead implant in the subthalamic nucleus and its associated "microlesion" effect impacts oscillatory activity in the hand area of motor cortex. METHODS We examined cortical local field potentials in 31 patients before and after subthalamic nucleus lead implant at rest and during repetitive voluntary and passive contralateral upper limb movements. We computed continuous wavelet transforms of the signals and correlated (1) baseline spectral power and motor symptom severity and (2) changes in spectral power and contralateral motor symptoms related to microlesion. RESULTS Baseline motor symptom severity correlated with high-frequency broadband power in primary motor cortex during voluntary movements (200-300Hz: Pearson's r = 0.51, p = 0.014, 95% confidence interval [CI]: [0.15, 0.75]; and 300-500Hz: r = 0.44, p = 0.038, 95% CI: [0.06, 0.70]). Motor improvements from lead implant correlated with decreases in high gamma power in primary sensory cortex during voluntary movements (70-200Hz: r = 0.44, p = 0.035, 95% CI: [-0.07, 0.62]). INTERPRETATION How motor parkinsonism alters electrophysiology in cerebral cortex is unclear. Our findings suggest that both the severity of parkinsonism and its improvement from the microlesion effect are associated most closely with changes in high-frequency oscillatory activity in primary sensorimotor cortex. Better understanding the cortical dynamics of movement disorders could guide novel paradigms for adaptive DBS. ANN NEUROL 2025.