Epilepsy as a dynamical disorder orchestrated by epileptogenic zone: a review

Abstract

Epilepsy is a group of chronic neurological disorders characterized with recurrent and hypersynchronous discharge. In the epileptic brain, epileptogenic zone (EZ) with abnormal firing patterns is considered as the culprit of hyperexcitable neuronal behaviors, increasingly manifested as alterations in dynamics. Meanwhile, the brain networks of epileptic patients show greater seizure susceptibility than those from healthy controls, referred as epileptogenic networks. There is a growing recognition of an intimate, but also complex, relationship between the self-organization of epileptogenic networks and abnormal dynamics of the EZ. In this review, we discussed the short- and long-term effects of recurrent epileptiform discharge on neural circuits, involving the regulation of connection weights and network topology. In addition, progressive abnormalities associated with secondary epileptogenesis imply that the excitability of regions connected with EZ may be enhanced, leading to frequent transitions from normal to epileptic states. From the perspective of network dynamics, EZ plays a dynamical pacemaker role in the evolution of epileptogenic networks as well as the activities generated by these networks. It may provide novel insights into the mechanism of epileptogenesis and inspire new therapeutic strategies.