Comparison of average sparks in WT and MO preparations. (Left) Averaged line-scan images of Ca²⁺ sparks with peak amplitude >0.5 ΔF/F, detected in WT (top) and morphant (bottom) preparations. Time and space profiles obtained from these average sparks are shown (middle and right, squares) along with the best fits of standard waveforms to these profiles (curves; see Materials and methods). Labels give spark parameters obtained from these fits; FDHM, full duration of the time profile at half-maximum amplitude. The sparks from morphant cells are smaller, briefer, and narrower than those from WT cells.