Figure 3. Gamma-IEDs from 9 patients are selectively localized to the SOZ compared with outside the SOZ (non-SOZ).

(A) Chart summarizing the proportion of gamma-IEDs relative to all other IEDs in the 9 patients with gamma-IEDs in the study. These general proportions are broken down into individual patients (right panel) with gamma-IEDs detected and show consistent distributions of macro- and microelectrode recorded events (values over the bars with macro- and microelectrodes [gray] and microelectrode only [black]). Notice that 6.0% of the gamma-IEDs were recorded only on microelectrodes. (B) Bar plot summary shows the localization of the mean IED counts without preceding gamma oscillations relative to the SOZ with no significant difference (p > 0.05, n = 2,570 IEDs inside, and 1,638 outside SOZ). Breakdown into individual patients (right panel) is provided. (C) Analogous summary as in B is plotted for gamma-IEDs showing significantly more gamma-IED detections in the SOZ (***p < 0.001, n = 773 IEDs inside, and 91 outside SOZ). Notice that gamma-IEDs are associated with the SOZ in 100% of patients (9/9) with gamma-IEDs, in contrast to the general IED population. (D) Association of interictal epileptiform spikes (IEDs), pathologic gamma oscillations (30–100 Hz), pathologic HFOs (100–600 Hz), and gamma-IEDs with SOZ (black) and non-SOZ (gray) is examined by aggregating the event counts for each region (*p < 0.05, ***p < 0.001). In summary, gamma (30–100 Hz) and ripple–fast ripple (100–600 Hz) HFOs were increased in SOZ, but gamma-IED complexes showed a stronger association with SOZ. HFO = high-frequency oscillation; IED = interictal epileptiform discharge; SOZ = seizure onset zone.