Data characteristics of each slice.

Kbath: final potassium concentration per slice, which was sufficient to elicit seizure-like events; nseiz baseline: number of spontaneous seizures before the stimulation experiment was started; ISI baseline: inter-seizure interval length (mean standard deviation) before the stimulation experiment; nseiz stim: number of seizure trials with stimulation (where pre-stim seizure trials without stimulation served as a matched control for assessing for relative ISI changes); ISI stim: ISI with stimulation, ISI pre-stim: ISI without stimulation preceding an ISI with stimulation, used as control.