Bilateral coherence between motor cortices and subthalamic nuclei in patients with Parkinson's disease

•Bilateral subcortico-cortical coherences were evident at rest in Parkinson's disease.•Peak frequencies of sub-beta and beta coherences were identical in each patient.•Subcortico-cortical coherences correlate with UPDRS motor scores in the OFF state.

ObjectiveIt has been suggested that abnormal synchronization and oscillation of neuronal activity in the subthalamic nucleus (STN) is associated with sensorimotor dysfunction in Parkinson's disease (PD). We investigated the bilateral subcortico-cortical functional coupling in PD patients.MethodsWe simultaneously recorded local field potentials from the bilateral STN using electrodes inserted for deep brain stimulation and electroencephalograms from the bilateral motor cortices (MCx) in 11 patients at rest, and analyzed their coherences and causalities.ResultsSignificant coherence in the sub-beta and beta frequency bands was simultaneously observed between the STN and contralateral STN (STN-cSTN), the STN and ipsilateral MCx (STN-iMCx), and the STN and contralateral MCx (STN-cMCx). In each patient, the frequency of the peak STN-cSTN coherence was similar to that of the peak STN-iMCx and STN-cMCx coherence. The causality between the STN and MCx was strongest in the one-way direction from the MCx to the ipsilateral STN.ConclusionsAbnormal oscillations in the STN in the sub-beta and beta bands were functionally coupled among bilateral STN and MCx at the eigen-frequency in individual patients with PD.SignificanceSynchronized activity through cortico-subcortical transmission may have an important role in the pathophysiology of PD.