Long-range correlations in fly ISIs.

If the slope of the log-log plots of the r.m.s. fluctuation (exponent α, see Methods) deviates significantly from ½, long-range correlations exist in the time series. All three fly groups show a significant deviation from 0.5. The deviation of branched Poisson processes (BPP), however, depends on the nonlinearity of the filter function used to drive the Poisson processes and is significantly smaller than that of fly ISI series. *-significant difference from 0.5.