Seizure-like activity and the definition of the neuronal avalanche. A, Orientation of the brain slice to the recording site. B-C, Typical traces of spontaneous and seizure activity, which could be induced by applying 4AP and Bic. D-E, Seizure-like activity was composed of ictal events, followed by tonic and clonic bursts. The filtered nLFPs were set at threshold to detect neuronal activity and are shown in the upper and middle panels. The time-point selected from the nLFPs of each channel at which the nLFPs exceeded the specific threshold is marked as a digital unit in the lower panel. F, Example of the collective time step, which is framed in 4 ms time bins from eight channels. The definition of an avalanche is separated by blank activity at the beginning and end of the events. The activated electrodes are counted as the avalanche size, and each event’s lifetime is the summation of the total time frame. G, Distribution of different avalanche sizes plotted on a log-log scale. The neuronal avalanche could follow the power-law distribution, and its slope could be calculated as the α value. The original data were shuffled in their spatiotemporal arrangement to disturb intrinsic dependency. Both the spontaneous activity and shuffling data show a Poisson distribution. Scale bar = 1 mm in A.