TMSi Expert Talk: Cortico-basal ganglia gamma and beta synchronization during action control

開催日時: 2020年10月20日: 23:00〜

講演者 :Petra Fischer, MSc PhD

Postdoctoral Neuroscientist @Nuffield Department of Clinical Neurosciences, University of Oxford - since 09/2017: Postdoctoral Neuroscientist at the MRC Brain Network Dynamics Unit and Nuffield Department of Clinical Neurosciences, University of Oxford - since 10/2018 Tilleard-Cole Junior Research Fellow in Neuroscience at Worcester College, University of Oxford - 10/2014-11/2017: DPhil in Clinical Neurosciences at the University of Oxford, UK, supervised by Prof. Peter Brown, thesis title: "Neuronal dynamics of flexible motor control in the human subthalamic nucleus and cortex" - 10/2011-12/2013 MSc in Cognitive Science at the University of Osnabrück, Germany




Dysfunctional cortico-basal ganglia (BG) processing can result in severely disrupted movement control as observed in Parkinson's disease, Huntington's disease and dystonia. Simple ballistic movements are accompanied by increased synchronization at relatively high frequencies (gamma = 60-90 Hz) while slower beta-rhythmic activity (13-30 Hz) is suppressed. Gamma and beta oscillations thus have been conceptualized to represent pro-kinetic and anti-kinetic processes, respectively. To uncover how the cortico-BG network supports more complex actions we recorded EEG activity and subthalamic nucleus (STN) local field potentials in Parkinson's patients in the following two tasks: Rapid stopping of a continuous finger tapping movement and smooth transitions between stable muscle contractions During rapid stopping of the ongoing tapping movement, STN gamma oscillations increased, transforming the previously held view of gamma oscillations being predominantly pro-kinetic. At the same time, phase coupling between STN and cortical gamma activity rapidly dropped, which may reflect a gating mechanism that can either facilitate movement by promoting network propagation of gamma activity or rapidly cancel it. During smooth stabilization of muscle contractions when performing gradual adjustments, beta oscillations dominated, suggesting that when neural dynamics need to be stabilized, the cortico-BG network relies on beta synchronization.