Involvement of the human hippocampus in secondarily generalized seizures of extrahippocampal origin

Objective: Recent data reveal that clinically generalised seizures do not truly involve all brain regions, but rather show focal accentuation. The hippocampus is a vulnerable tissue with high epileptogenic potential which might be protected against epileptic activity due to the low-pass filtering properties of the dentate gyrus. To investigate if generalised seizures spare the hippocampus, we examined to what extend secondarily generalised tonic-clonic seizures (SGS) of extrahippocampal onset (EHO) propagate into the hippocampus and if there are differences between patients with or without apparent hippocampal p…