Fig. 2.

Leak K⁺ channels play a role in generating the SWS firing pattern based on the SAN model. (A) Scatter plot of the g_K and g_Ca values for all 1,008 parameter sets obtained by the parameter searches. All parameter sets were divided into two clusters, cluster 1 (blue) and cluster 2 (orange), according to the g_K and g_Ca values. (B) Membrane potential and intracellular Ca²⁺ concentration of the representative parameter set in each cluster over time. (C) Membrane potential, proportion of each channel’s inward current, and proportion of each channel’s outward current of the representative parameter set in each cluster over time. (D) Bifurcation analysis of the representative parameter set in each cluster. The definitions and examples of SWS, awake, resting, and slow-wave with few spikes are described in SI Appendix, Fig. S2E and Table S5, respectively. (E) Two-dimensional bifurcation analysis of the representative parameter set in cluster 1. (F) Three- (Upper) and two-dimensional (Lower) plots of the trajectory of the representative parameter set in cluster 1. (G) Phase planes of the representative parameter set in cluster 1 in cases in which the Ca²⁺ concentration is fixed at 7 μM, 8.5 μM, 10.6 μM, or 12.5 μM. The red, green, and blue lines indicate the trajectory of the differential equation, V nullcline, and n_K nullcline, respectively. (H) Membrane potential and phase plane of the parameter set whose g_KCa was lower (Left) or whose g_KCa and g_KL were lower (Right) than the representative parameter set in cluster 1. (I) Summary of the bifurcation analysis in cluster 1. Conductance of the leak K⁺ channels is in red.