BrainLinks-BrainTools is inviting all members, colleagues and friends to a guest lecture by Dr. Brice de la Crompe from the University of Bordeaux:
Circuit mechanism of Beta-oscillation expression in basal ganglia
Abstract: The basal-ganglia (BG) form a complex loop with the cortex and the thalamus that is involved in action selection and movement control. Synchronized oscillatory activities in basal-ganglia neuronal circuits have been proposed to play a key role in coordinating information flow within this neuronal network. If synchronized oscillatory activities are important for normal motor function, their dysregulation in space and time could be pathological. Indeed, in Parkinson’s disease (PD), many studies have reported an abnormal increase in the expression level of neuronal oscillations contain in the beta (β) frequency range (15-30 Hz). These abnormal β oscillations have been correlated with two mains symptoms of PD: akinesia/bradykinesia. However, which BG neuronal circuits generate those abnormal β oscillations, and whether they play a causal role in PD motor dysfunction is not known. The subthalamic nucleus (STN) is a key nucleus in BG that receives converging inputs from the motor cortex (mCx) and the globus pallidus externalis (GP). Here, we used a rat model of PD combined with in vivo electrophysiological recordings and optogenetic silencing to investigate how selective manipulation of mCx, STN and GP causally influence BG network dynamic. Our data challenge the implication of mCx in the propagation mechanisms of abnormal β-oscillations and highlight the causal role of GP in the maintenance of these hyper-synchronized activities in dopamine-depleted state.