| Summary: | <h4>Objective</h4> <p>High-amplitude beta band oscillations within the subthalamic nucleus are frequently associated with Parkinson’s disease but it is unclear how they might lead to motor impairments. Here we investigate a likely pathological coupling between the phase of beta band oscillations and the amplitude of high-frequency oscillations around 300Hz. </p> <h4>Methods</h4> <p>We analysed an extensive data set comprising resting-state recordings obtained from deep brain stimulation electrodes in 33 patients before and/or after taking dopaminergic medication. We correlated mean values of spectral power and phase-amplitude coupling with severity of hemibody bradykinesia/rigidity. In addition, we used simultaneously recorded magneto-encephalography to look at functional interactions between the subthalamic nucleus and ipsilateral motor cortex.</p> <h4>Results</h4> <p>We analysed an extensive data set comprising resting-state recordings obtained from deep brain stimulation electrodes in 33 patients before and/or after taking dopaminergic medication. We correlated mean values of spectral power and phase-amplitude coupling with severity of hemibody bradykinesia/rigidity. In addition, we used simultaneously recorded magneto-encephalography to look at functional interactions between the subthalamic nucleus and ipsilateral motor cortex.</p> <h4>Conclusions</h4> <p>We speculate that the beta band might impede pro-kinetic high-frequency activity patterns when phase-amplitude coupling is prominent. Furthermore, results provide evidence for a functional subdivision of the beta band into low and high frequencies.</p> <h4>Significance</h4> <p>Our findings contribute to the interpretation of oscillatory activity within the cortico-basal ganglia circuit.</p>
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