title: Understanding ictogenesis in generalized epilepsies.
abstract: Generalized seizures are defined by bilateral symmetric and synchronous epileptiform EEG discharge over the entire convexity and commonly thought to involve the entire brain homogeneously. The characteristic 3-3.5 Hz Spike-and-Wave pattern is conceived as a resonance phenomenon originating in a cortico-thalamic circuit where it can start at variable sites. Investigations with EEG source analysis, magnetencephalography, positron emission tomography and single photon emission computerized tomography, functional magnetic resonance imaging and transcranial magnetic stimulation have suggested that generalized seizures have cortical onset and the thalamus has an essential role in the recruitment of a network comprising frontal, parietal and occipital cortex and the default mode network. Studies of reflex epileptic traits have shown that 'generalized' ictogenesis largely uses pre-existing functional anatomic networks normally serving physiological functions. It has therefore been proposed to consider these epilepsies as system disorders of the brain. Treatment is fundamentally pharmacological with a role for behavioral interventions. Generalized epileptic encephalopathies of early childhood are sometimes surgically remediable.
authors.affiliation: Danish Epilepsy Centre, Kolonivej 2, DK - 4293 Dianalund, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Wolf
authors.forename: Sándor
authors.initials: S
authors.lastname: Beniczky
mesh_terms: D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D004569:Electroencephalography; D004829:Epilepsy, Generalized / Q000145:classification / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D059906:Neuroimaging
keywords: cortico-thalamic network; default mode network; epileptic network; functional imaging; generalized epilepsy; ictogenesis; reflex epilepsy; source analysis; system epilepsy