Oscillations Induced by Brain Connectivity Changes in Basal ganglia-cortex Network

Synchronous oscillatory activities of the biological neural network are the basis for the brain to implement different functions, while abnormal oscillations of basal ganglia-cortex circuits in the range of12-35 Hz are correlated with Parkinson`s disease. A kind of lumped parameter model to characterize the properties of the neural mass is proposed to reproduce the observed neural activities both under normal and Parkinsonian state. By analyzing the firing pattern and power spectrum characteristic of each brain nucleus under different brain connectivities, it is shown that increased intra-coupling strengths perform an important role in inducing abnormal oscillations in the high-beta frequency band (20-35Hz) in cortex and the low-beta frequency band (12-20Hz) in basal ganglia. To elucidate the mechanism underlying the transition between different brain states, the dynamics of each nucleus and the connectivity properties are explored. Simulation results suggest that the normal neural system could be driven into Parkinsonian state due to the increase of inhibitory projections from basal ganglia to cortex or excitatory projections from cortex to basal ganglia. This work may pave the way to the exploration of the generation mechanism of the abnormal oscillations related to Parkinsonian movement disorders.