Figure 4.

Networks become more similar during — and between — seizures. (A) Two examples of networks from a preictal interval (unshaded) and ictal interval (shaded) from two different seizures of a single subject. Visual inspection suggests that the ictal networks are more similar both within each seizure (i.e., within each shaded region), and between the two seizures (i.e., between the two shaded regions), compared to the preictal networks. The arched (straight) lines indicate example intra-seizure (inter-seizure) comparisons. (B) The similarity between networks within each interval of the same seizure (i.e., intra-seizure similarity, solid curve) and between intervals of different seizures from the same subject (i.e., the inter-seizure similarity, dashed curve). The intra-seizure similarity increases during seizure; networks become more similar within ictal intervals compared to preictal intervals. The inter-seizure similarity, which compares networks from the same interval but different seizures of a subject, also increases during seizure. For both curves, circles denote the mean value (n={82059, 10222, 30666}) of intra-seizure comparisons for the preictal, ictal, and postictal intervals, respectively, and n={277537, 40169, and 120507} inter-seizure comparisons for the preictal, ictal, and postictal intervals, respectively, adjusted for differences in subjects; the vertical lines denoting the standard error are no larger than the black or gray circles. Statistically significant changes from the preictal value are indicated in gray (see Methods).