Calcium conductance-dependent network synchronization is differentially modulated by firing frequency

Abstract

Synchronous oscillations in certain frequencies of the sub-thalamic nucleus (STN) neurons are closely related to the physical symptoms of Parkinson's disease (PD). Recent results have highlighted the importance of calcium channels in the synchronization properties and regulation of STN neurons. In this paper, a novel hybrid neuron model which can capture the electrophysiological signature of neurons with low or high density of calcium channels is used to explore the synchronization propensity and regulation by firing frequencies of neurons. Numerical simulations show that the synchronization propensity of networks consisting of the novel hybrid neurons is quite distinguishing in low and high calcium conductance modes, especially, the synchronization can be differentially modulated by network frequencies in the two modes. By analyzing the firing frequency and phase response curve of the individual neuron, we find that a single parameter of the hybrid neuron, which is a direct image of the calcium conductance, is crucial in determining the excitability and response properties of the neuron. Different phase response properties of single neurons in different calcium conductance modes lead to network synchronization discrepancies.