The pathophysiology of focal epilepsy: neurophysiological considerations.

The study of epilepsy serves to emphasize the importance of integrating basic research with clinical data. In this selective review, the results of recent experiments using intracellular recording techniques, ion-specific microelectrodes, and a methodology suitable for studying mammalian cortex in vitro are discussed in terms of cellular phenomena which underlie clinical observations made in epileptic patients. This information has begun to clarify: (1) the changes in neuronal behavior associated with interictal and ictal events; (2) alterations in local ionic microenvironment which occur during focal epileptogenesis; (3) intrinsic control mechanisms which serve to restrict seizure spread; (4) neuronal characteristics which account for the differences in seizure patterns seen in infants and adults; and (5) the possible long-term consequences of recurrent local neuronal hyperexcitability.