Fig. 9: Suppression of spontaneous SDs enhances seizure intensity and generalization.

A Left panel: Diagram showing electrode (E1-E3) and ROI (1–5, C) placement. Representative ECoG tracings showing seizure generalization to the remote ipsilateral (E2) and contralateral (E3) electrodes. Such synchronized electrophysiological generalization was common in the MK-801 group but rarely observed in control animals that were allowed to develop SDs. B Averaged ECoG power time courses normalized to pre-seizure baseline are shown separately for each electrode and frequency band. Seizure generalization to the remote ipsilateral (E2) and contralateral (E3) electrodes is significantly higher in the MK-801 group (bold symbols) that did not develop any SD compared with time controls that were allowed to develop spontaneous SDs (4AP alone, faint symbols). Seizure intensity at the local electrode (E1) is much less affected (only in 8–12 Hz band). Red arrowheads show the time of the 4AP application. Exact p values are shown on the graphs (two-way ANOVA for repeated measures; ±SEM). C The proportion of animals that developed hyperemia within each of the six ROIs coupled to 4AP seizures are shown with and without MK-801 treatment. The proportion of animals that showed hyperemic transients in the contralateral ROI (c) was significantly higher in the MK-801 group compared with controls (p = 0.001, χ²). The average distance hyperemic transients reached from the drug application site was significantly higher in the MK-801 group (p = 0.040, t-test with Welch’s correction; red circles; no hyperemic transients in any ROI = 0; ±SEM).