Computational modeling of circadian firing activity in single suprachiasmatic nucleus neuron

Abstract

The suprachiasmatic nucleus(SCN) is a self-sustained circadian rhythm generator in the mammal. The internal molecular oscillations create circadian change of physiological signals those come out with high firing frequency in day time and low firing frequency at night. The underlying physiological mechanism and relationship between components of contributed channels are still unknown. We tried to find a biologically faithful model simulation of SCN channel contribution to circadian rhythm. We constructed computational model of spontaneous firing SCN neuron and tested with experimental evidences in previous studies. After verification of the model, we investigated spontaneous firing rate (SFR) with variations of conductance in specific channels mainly contributing SFR change. Simulation of channels correlated with SFR and reconstruction of day/night circadian rhythmic firing rate change could show the underlying principles of physiological mechanisms in SCN neuron. We also checked the circadian firing rhythm with conductance change in time and predicted cuspidal shape of conductance change for sinusoidal circadian firing pattern. With these predicted parameters we reproduced sinusoidal circadian firing rhythm. This study showed the possibility of controlling multi variables with voluntary time with SCN neuron model and developing model of SCN neuron activities (i.e. network model).