The Functional and Structural Impact of Epileptic Seizures on the Adult Brain
Introduction and Definitions
Spontaneous epileptic seizures are generated by brain circuits, whose functional architecture is modified. This raises three important questions: does the reorganization of neuronal circuits precede the occurrence of the first spontaneous seizure? Do spontaneous seizures contribute directly to the reorganization of the circuitry? What is their impact upon the cognitive functions, which are controlled by modified circuits?
These are chicken-and-egg type of questions, since all processes are likely to be intermingled.
Any “normal” brain can display a seizure, e.g., after an electroshock, a severe brain trauma, drug overdose, etc. This suggests that seizures can use the pathways of a “normal” network, but not in normal conditions, only when the system is pushed far enough. What then allows their expression in the absence of any major triggering event? Numerous studies performed in animal models investigating epileptogenesis, the process leading to the...