The epileptic brain: insights to be gained from intracranial EEG recordings and cortical stimulation
Epilepsy surgery can be remarkably successful in some patients, resulting in seizure freedom despite multi-drug resistance, yet much less effective in others. Intracranial (ic) EEG recordings are often needed to map seizure onset zone (SOZ) and eloquent cortex. Patients with focal fast discharges at seizure onset have a favourable prognosis after resection. Informing extent of resection, however, may be challenging, with often rapid spread to adjacent and remote areas. Presently, little is known about seizure onset and propagation, but network dynamics of the SOZ and of connected cortical areas are likely critical determinants for success of resection.
Patients with implanted electrodes provide an opportunity to investigate a range of important questions. We can explore a number of neurophysiological correlates of to characterize areas of epileptogenicity and of ictal onset. Further we can study the response to functional mapping of eloquent cortex and also look at brain responses to single pulse stimulation (or other stimulation parameters) from the seizure onset zone and connected areas. Lastly, this allows an unparalleled opportunity to understand connectivity in the human brain.
For this informal discussion, I plan to show a number of cases to stimulate exchange of ideas to improve our understanding of brain responses to stimulation and of connectivity in the epileptic brain.