Representative time sequence of [Ca ²⁺ ] profiles in the cytoplasm (left panels) compared with locations of sparks and embers (right panels). The cell long axis of symmetry (i.e., the cell center) is at x = y = 0. A complete set of images at 100-ms intervals is given in Fig. S7. The z-t fluorescent line scan for this Ca²⁺ wave is shown in Fig. 6 A using the same time reference. Blue dots indicate locations of sparks, and red dots indicate embers (Ca²⁺ release events with duration >50 ms). The upper-left panels show the x-y plane indicated by the dotted line in the lower-left panels, and the lower-left panels show the x–z plane indicated by that in the upper-left panels. Release events along the z axis are shown throughout the entire cell volume viewed 1° rotated from the y-direction to avoid obscuring release sites.