Fig. 3.
Ca2+ sparks appear in both the periphery and the center of dedifferentiating muscle fibers. A: 50 sequential full-frame fluorescence images of a muscle fiber loaded with fluo 4 after being maintained in a serum-containing culture for 7 days. B: events selected from A as being within the selection criteria of contiguous pixels >2 SD above the mean of the same pixel, with at least one pixel >3 SD above the mean. Each selected event is shown within an enclosing box in the image. Successive images were recorded at 3-s intervals.