Summary of descriptive statistics of the 6-week-long fibroblast recordings (n = 80 cells from 2 cultures).

After eliminating several days at either end of the data series to avoid edge effects and initial transients, 34 cycles were used for calculating cycle length and amplitude statistics of each cell. The period of each cell's time series was calculated using maximum entropy spectral analysis (MESA) and also as mean peak-to-peak time. Coefficient of variation (CV), a dimensionless measure of variability, equals the standard deviation divided by the mean. Brightness (photons/min) equals mean intensity over 34 days of recording.