Fig. 6.

A: Monte Carlo sampling of blip/spark duration and amplitude (integrated Ca²⁺ release) for the standard (solid circles) and tetracaine-based (open circles) parameter sets. Each blip or spark was initiated by a N_O = 0 → 1 transition (cf. Fig. 5, where N_O = 4 → 5 was interpreted as a spark initiation event). B and C: cumulative probability distribution of spark amplitude (B) and duration (C) for the standard (solid line) and tetracaine-based (dashed line) parameter sets. The amplitude of release is expressed in units of femtocoulombs under the assumption of a total myoplasmic volume of 2 × 10⁻⁵ μl and 2 × 10⁴ release sites per cell (see Supplemental Material). D: percentage of “hidden” (undetected) spark events and percentage of Ca²⁺-release flux mediated by hidden sparks as a function of the spark amplitude detection threshold.