A hypothesis of series resonance in the white matter for understanding the mechanism of spike-wave seizures

Abstract

Generalized epilepsy is accompanied by large-amplitude synchronized spike-wave discharges on electroencephalography. The condition rapidly and synchronously involves most regions of the brain, but the mechanism underlying this global involvement remains unclear. Here I attempt to clarify this phenomenon by hypothesizing a series resonance in an equivalent electric circuit for the white matter. This hypothesis is based on the ideas that the electric conduction along an axon is due to the displacement current, and the unit structure composed of a node of Ranvier and the next node can be regarded as a capacitor or an inductor, depending on the geometry and the substance around the nodes. The flash-visual evoked potentials at various flash repetition rates were measured in generalized epilepsy patients, and compared with those for healthy controls and focal epilepsy patients. The P₁₀₀ amplitude plotted against the flash repetition rate had a maximum peak at a certain flash repetition rate only for each of the generalized epilepsy patients. The observation of a peak in the P₁₀₀ amplitude was inferred to reflect the series resonance phenomenon in the white matter. I speculate that patients with generalized epilepsy have large regions of white matter with similar resonance frequencies.