Size distributions for avalanches follow power laws independently of bin width Δt. A, Probability distribution of avalanche sizes (number of electrodes activated) in log-log coordinates at different Δt (average for n = 7 cultures). The linear part of each function indicates power law. Cutoff given by maximal number of electrodes (n = ∼60). Inset, Dependence of slope α on Δt: α(Δt) ∼ Δt^{-0.16 ± 0.01} (R² = 0.99 ± 0.01; averages for all cultures). Circles, Electrodes; squares, LFP. B, Probability distribution of avalanche size distributions based on summed LFPs as a function of bin width Δt. Inset, Single culture; overplot of power laws for all seven cultures at Δt = 1 msec expressed in multiples of average LFP size.