Driving motor cortex oscillations restores plasticity and improves bradykinesia features in Parkinson’s disease
摘要
In Parkinson’s disease (PD), impaired plasticity of the primary motor cortex (M1) contributes to bradykinesia. Enhancing cortical γ oscillations through transcranial alternating current stimulation (tACS) restores M1 plasticity, but whether this translates into bradykinesia improvement remains unclear. We conducted a double-blind, sham-controlled study to determine whether M1 γ-tACS improves intermittent theta burst stimulation (iTBS)-induced plasticity and alleviates bradykinesia in PD. Forty participants (20 patients and 20 healthy controls - HCs) underwent two randomized sessions: iTBS-γ tACS and iTBS-sham tACS. We assessed corticospinal excitability and GABA-A-ergic-related intracortical inhibition using transcranial magnetic stimulation, and bradykinesia features through finger-tapping kinematic analysis before and 5, 15, and 30 min after iTBS-tACS. iTBS-sham tACS failed to induce M1 plasticity in PD, whereas iTBS-γ tACS elicited M1 plasticity (p = 0.006) and improved SICI (p = 0.004). These neurophysiological changes in PD were paralleled by improvement in bradykinesia features, i.e., faster and wider movements (all ps < 0.001). No changes were observed following iTBS-sham tACS or in HCs. SICI γ-tACS-induced changes correlated with the clinical score in patients (r = 0.68, p < 0.001), and plasticity changes correlated with velocity improvement (r = 0.61, p = 0.003). γ entrainment restores M1 plasticity and GABA-A activity, alleviating bradykinesia in PD with effects persisting beyond stimulation. These findings have translational relevance and offer insights into bradykinesia pathophysiology (ClinicalTrials.gov Identifier: NCT06297538, registration date March 7, 2024).