Spatial distribution of nonlinear interactions in subthalamic nucleus local field potentials in Parkinson'S disease

Abnormally synchronized neural oscillations within the subthalamic nucleus have been proposed as a contributor to the pathophysiology of Parkinson's disease. Recent studies have demonstrated phase-amplitude coupling between beta rhythms and high frequency oscillations in the subthalamic nucleus in unmedicated Parkinsonian patients. However, the nature of this coupling remains unclear. In this study, we first show the presence of nonlinear interactions between different frequency bands of oscillations. Then, we demonstrate that the amplitude of spatially localized high frequency activity is phase coupled with widespread beta oscillations within the subthalamic nucleus.