Uncoupling the roles of firing rates and spike bursts in shaping the STN-GPe beta band oscillations

by Jyotika Bahuguna, Ajith Sahasranamam, Arvind Kumar The excess of 15-30 Hz (β-band) oscillations in the basal ganglia is one of the key signatures of Parkinson ’s disease (PD). The STN-GPe network is integral to generation and modulation ofβ band oscillations in basal ganglia. However, the role of changes in the firing rates and spike bursting of STN and GPe neurons in shaping these oscillations has remained unclear. In order to uncouple their effects, we studied the dynamics of STN-GPe network using numerical simulations. In particular, we used a neuron model, in which firing rates and spike bursting can be independently controlled. Using this model, we found that while STN firing rate is predictive of oscillations but GPe firing rate is not. The effect of spike bursting in STN and GPe neurons was state-dependent. That is, only when the network was operating in a state close to the border of oscillatory and non-oscillatory regimes, spike bursting had a qualitative effect on theβ band oscillations. In these network states, an increase in GPe bursting enhanced the oscillations whereas an equivalent proportion of spike bursting in STN suppressed the oscillations. These results provide new insights into the mechanisms underlying the transientβ bursts and how duration and power ofβ band oscillations may be controlled by an interplay of GPe and STN firing rates and spike bursts.
Source: PLoS Computational Biology - Category: Biology Authors: Source Type: research