Chapter

Neurophysiology of Epilepsy

Florin Amzica

in Oxford Textbook of Epilepsy and Epileptic Seizures

Published on behalf of Oxford University Press

Published in print December 2012 | ISBN: 9780199659043
Published online December 2012 | e-ISBN: 9780191751363 | DOI: http://dx.doi.org/10.1093/med/9780199659043.003.0001

Series: Oxford Textbook of

Neurophysiology of Epilepsy

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This chapter is devoted to defining some of the mechanisms that determine the behaviour of cellular membranes, both of neurons and glial cells, during the transition towards epileptic discharges and henceforth during seizures. We take the view that epileptic events are not the sole result of concerted populations of neurons, but equally important, of the dialogue between neurons, glial cells and, especially their extracellular environment. We insist on the fact that during some types of seizures, especially the ones of the grand mal type, the hypersynchronization of cerebral territories is not likely to be the work of cortical synaptic linkages because extracellular calcium levels are critically low and would not endow neuronal networks with the necessary synaptic strength. On the other hand, networks of glial cells easily communicate through gap junctions over large territories and are the main synchronizer of epileptic events. Here we emphasize the role of the extracellular potassium in signalling and modulating the glial and neuronal membranes. The chapter also includes some thoughts about the role of the cortex in starting seizures and puts it into perspective with respect to centrencephalic theories.

Chapter.  7022 words.  Illustrated.

Subjects: Neurology

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