Fig 15. Criticality in Ca²⁺ spark propagation.

Aa) Histogram of the nearest neighbours for each dyad in the structurally detailed model and b) probability of Ca²⁺ spark-induced-spark propagation in a two-dyad model at different SR Ca²⁺ concentrations (indicated in the figure legend). The dyad distribution is imposed for reference and the mean nearest neighbour inter-dyad distance is show by the dotted line. B) Ca²⁺ spark hierarchy at different mean nearest neighbour distances (left to right) for different SR Ca²⁺ loads (top to bottom), simulated in the cross-sectional portion cell model.