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Modeling the Electrophysiology of Suprachiasmatic Nucleus NeuronsInstitute of Bioengineering and Nanotechnology, The Nanos, Singapore
Department of Mathematics, University of Michigan, Ann Arbor, MI, forger{at}umich.edu, Center for Computational Medicine and Biology, and Department of Physics, University of Michigan, Ann Arbor, MI Neurons in the SCN act as the central circadian (~24-h) pacemaker in mammals. Using measurements of the ionic currents in SCN neurons, the authors fit a Hodgkin-Huxley-type model that accurately reproduces slow (~2-8 Hz) neural firing as well as the contributions of ionic currents during an action potential. When inputs of other SCN neurons are considered, the model accurately predicts the fractal nature of firing rates and the appearance of random bursting. In agreement with experimental data, the molecular clock within these neurons modulates the firing rate through small changes in the concentration of internal calcium, calcium channels, or potassium channels. Predictions are made on how signals from other neurons can start, stop, speed up, or slow down firing. Only a slow sodium inactivation variable and voltage do not reach equilibrium during the interval between action potentials, and based on this finding, a reduced model is formulated.
Key Words: circadian rhythm neuron model calcium sodium inactivation SCN
Journal of Biological Rhythms, Vol. 22, No. 5,
445-453 (2007) This article has been cited by other articles:
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