Figure 4.

Interictal-spike and sharp-wave activity at 2 and 6 months after HI treatment. A, At 2 months, interictal spikes were often only recorded from the parainfarct electrode (Ch2). B, In other cases after 2 months, interictal spikes were recorded at both the parainfarct site (Ch2, PE) and over the infarct (Ch1, IE) with a clear onset of spike clusters adjacent to the lesion. Spike activity was rare on the contralateral electrode (Ch3, CE) at 2 months. C, D, After 6 months, the chronically epileptic rats showed interictal activity of variable frequency on the ipsilateral electrodes (Ch1 and Ch2) that was also consistently present on the contralateral electrode (Ch3). C, When interictal spikes were recorded on all three electrodes, the frequency could differ across the three channels (e.g., a lower frequency is shown on Ch2 compared with Ch1 and Ch3). D, When spikes occurred between seizures within a cluster, interictal spike frequency was higher (∼1 Hz) than between clusters. A1, B1, C1, and D1 illustrate individual spikes (<70 ms) and sharp waves (70 to 200+ ms) from near the center of the respective traces.