Morphological study of human epileptic dendrites.

We studied 14 human epileptogenic foci with light and electron microscopy to establish their morphological patterns. Using silver staining techniques, we found dendritic areas devoid of spines, dendritic angulations, and nodular or segmentary dendritic swellings. When these findings were compared with the morphology of nonepileptic cortex, only the existence of dendritic swellings in the epileptic tissue was significant. Electron microscopy showed that the nodular dendritic swellings were due to an alteration in the normal arrangement of the microtubules. We hypothesize that an alteration in the microtubular arrangement causes a mechanical distortion of the dendritic membrane and subsequently may cause its depolarization.