Neuronal circuits in epilepsy: do they matter?

Seizures occur in groups of neurons and involve complex interactions across several regions. The focus of much epilepsy research has been on changes in single neuronal populations but the interpretation of the implications of these changes is often limited by not being able to place those observed changes appropriately in the overall function of the brain. Understanding regional interactions at the beginning and during the evolution of a seizure may help place the changes in the appropriate context of the pathophysiology of epilepsy and guide us in identifying more effective therapies. In this paper we will focus on the circuits that support the different stages of seizures. Although we are far from knowing how the system works to initiate and spread seizures, we hope to provide a framework upon which we can place cellular changes. The concepts of seizure focus, initiating seizure circuits, paths of spread and neuromodulatory centers will be used to develop a system's view of epilepsy.