Figure 6

Spontaneous and evoked SLEs and epileptic burst activity observed after 3, 24 and 48 hours of incubation. (A) Spontaneous SLE was observed in normal aCSF after 48 hours of incubation, with a high frequency onset of 200 Hz and three terminating bursts. (B) Epileptiform burst activity recorded after 3 hours of incubation with 12–25 s long burst-trains every 3–11 min with 10–16 bursts in each train. The bursts consisted of up to five APs and each burst-train lasted 12–29 s. Between each burst the membrane potential returns to baseline until the onset of the next burst. (C) In slices incubated for 24 hours, SLEs with more than 150 Hz firing frequency at the onset and approximately 60 Hz in the following bursts were evoked by excluding Mg²⁺- from the aCSF. (D) By adding 4-AP to the [0Mg²⁺]-aCSF solution the activity became regular, with 150 Hz at the onset and around 40 Hz during the following bursts. (E) Example of regular bursts from a cell while perfused by the [0Mg²⁺]-aCSF solution with 4-AP added. (F) After 48 h of incubation it was still possible to evoke SLEs under perfusion of the [0Mg²⁺]-aCSF solution with 4-AP added.