Basic mechanisms of epileptic seizures

ABSTRACT

The results of recent experimental studies continue to enhance the understanding of basic mechanisms involved in epileptogenesis. Intracellular recordings from both in vivo and in vitro preparations have defined essential elements that underlie the pathologic firing patterns characteristic of "epileptic neurons." Generation of epileptogenic discharges depends on the interplay of three major factors: (1) the inherent capacity of some neurons to elaborate active responses that lead to paroxysmal bursting; (2) the breakdown of normal inhibitory mechanisms and the augmentation of excitatory synaptic activities; and (3) the biasing effect on these processes of modulating neurotransmitter substances which help to maintain pathologic discharges. Differences between acute and chronic foci probably depend more on the degree and intensity of these factors than on fundamentally different mechanisms.