During brief epileptic bursts, principal neurons fire together for tens to hundreds of milliseconds, producing a large extracellular potential ("field"). Superimposed on this large field are high-frequency oscillations, from ~100 to several hundred Hz. Two distinctive means of coupling between neurons cooperate to generate the event. Recurrent excitatory synaptic connections shape the overall event, but gap junction coupling produces the fast oscillations. I will describe the dissection of the cellular mechanisms via in vitro experiments and via computer modeling and network theory. Experimentally, the fast oscillations can be evoked alone, during blockade of chemical synapses; but blockade of gap junctions abolishes BOTH the fast oscillations and the larger burst. These data suggest that a targeted manipulation of selected gap junctions might prevent certain seizure events.