Supplementary Figure 2.

Supplementary Figure 2: Prolonged SLDs were still consistently present after pharmacological blockade of AMPA/kainate and NMDA receptors, although SLD duration and frequency were usually altered. A. Diagram shows the similar temporal features of the protocol as in Supplementary Figure 1. B. Glutamate-receptor antagonists (DNQX, 50 µM and AP-5, 50 µM) blocked responses to Shaffer Collateral stimulation. B1. Evoked PSPs and the negative population spike were recorded in CA1 after electrical stimulation of the Schaffer collateral pathway. These responses were similar to evoked responses under the control condition in Figure 3. B2. After addition of glutamatergic antagonists, the evoked synaptic response was strongly depressed. C. SLDs continued to occur spontaneously after glutamatergic synaptic responses were blocked. C1. SLDs were recorded in the hippocampal CA1 region in low [Ca 2+ ] ex and high [K + ] ex and were still present after bath application of the glutamatergic blockers (n = 59-67 SLDs, 5 slices, 5 rats) ( C2) . Boxed parts of the recordings are expanded below. D-E. The effect of bath application of the two glutamate-receptor antagonists on the duration and frequency of the SLDs was variable across the different slices. Similar to Supplementary Figure 1D-E, the quantification of SLD duration is shown for all SLDs ( D1 ) in addition to the mean values ( D2 ) and percent change ( D3 ) for each animal. A mixed-effects model was conducted to examine the effect of glutamatergic blockers on the duration of seizures. The results indicated that these blockers did not have a significant effect on seizure duration, F (1,123.78) = 0.99, p = 0.321. Note that in D, the duration of every SLD (59-67 SLDs; n = 5 slices, rats; mixed effects model) from all slices is quantified. Mean data from each animal shows that SLDs persisted but usually at a lower frequency following glutamatergic blocker application ( E1, E2 ). These results show that glutamate blockers variably altered the duration and frequency of the SLDs; ...