Effects on synchronized neuronal events of acute surgical separation of CA3 from CA1 illustrates the importance of CA3 pacing on CA1 firing. (A) Schematic diagram showing the surgical separation of CA3 from the remaining slice. (B) Synchronized neuronal firing under Mg2+-free conditions in slices is disrupted following CA3 separation. Events in CA1 and CA3 are no longer in phase or of similar frequency. (C) IBI of synchronized events in CA1 following separation from CA3 in both control and KA-treated slices (mean ± SEM, * p < 0.05, n = 6, one-way ANOVA). (D) Duration of bursts in CA1 following CA3 removal in both control and KA-treated slices (mean ± SEM, * p < 0.05, n = 6, one-way ANOVA).