Figure 14.
F(x,t) images illustrating different types of repetitive activity related to SR Ca2+ release. (A) Repetitive sparks. The autodetection routine identified 11 sparks in this 43 μm × 1.571–s image; mean resting F in the image was 5.8 counts/μs. All sparks occurred at the z-line located second from the top. 10 of the sparks passed the analysis criteria described in materials and methods and had a peak amplitude ≥ 0.7 ΔF/F (after F′/F scaling). The mean ± SEM values of the morphological parameters for these sparks were as follows: rise time, 3.12 ± 0.26 ms; peak amplitude, 1.12 ± 0.08 (after F′/F scaling); decay time constant, 3.78 ± 0.45 ms; FDHM, 4.41 ± 0.23 ms; late offset, −0.01 ± 0.01; FWHM, 0.94 ± 0.09 μm; mass, 1.43 ± 0.40 μm3. (B–D) Examples of sustained nonspark-like activity (see text). The sampling period and vertical extent of the images are 2.048 ms and 25.2 μm in B, and 1.024 ms and 17.3 μm in C and D. Fiber references are as follows: A, z080800b; B, z083000b; C, z082800a; D, z082800b.