Figure 2. Spatial and temporal properties of Ca²⁺ dynamics.

(A) Cartoon of four spatial scales of Ca²⁺ dynamics. Blips involve only one receptor activated channel. Puffs involve more than one receptor-activated channel (IP₃R or RyR). In a spike, the entire cell is active, and Ca²⁺ may spread to adjacent cells. An intercellular Ca²⁺ wave (ICW) involves multiple full-cell responses that are chained together, resulting in a self-sustaining transient of Ca²⁺ signaling across an entire tissue. Arrows represent the diffusion of the Ca²⁺ signal dynamics. (B) Several examples of Ca²⁺ signals. Shown is a slow change in Ca²⁺ concentration, a sinusoidal Ca²⁺ oscillation, and Ca²⁺ oscillation spikes. An oscillatory signal can contain more information than a static signal including oscillation Frequency, Amplitude, Basal concentration, and Width at Half Max (WHM). (C) Example of how a dynamic signal can be decoded to activate one of two different targets. In this case, the red signal is a non-oscillatory sustained increase in basal Ca²⁺ concentration, and the green signal is an oscillatory signal with high frequency and low amplitude and WHM. MLCK has a low activation threshold and can detect the change in basal concentration caused by the red signal. NFAT has a slow decay rate and can accumulate after many individual Ca²⁺ oscillations.