Elsevier

Experimental Neurology

Volume 9, Issue 4, April 1964, Pages 305-326
Experimental Neurology

Cortical cellular phenomena in experimental epilepsy: Ictal manifestations

https://doi.org/10.1016/0014-4886(64)90026-3Get rights and content

Abstract

After establishing an epileptogenic “focus” in the cat's cerebral cortex, an intracellular analysis from the involved elements was carried out during the development and course of the organized rhythmical electrographic seizures simultaneously monitored with surface electrodes. Neurons were classified on the basis of their behavior as active or passive. In the former, changes in membrane polarization were observed which characterized the various phases of the ictal episode. The previously present paroxysmal hyperpolarization shifts disappear at the onset and a prominent afterdepolarization develops. During the tonic phase the membrane potential markedly decreases and rhythmical oscillations with (or rerely without) action potentials appear above a sustained excessively depolarized membrane potential level. The clonic phase corresponds to a slow repolarization process and the end of the episode seems to be due to inactivation rather than to true membrane hyperpolarization. Some neurons appear to be activated only in the later phases of the seizure.

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    Present address of Dr. H. Matsumoto: University of Tokyo School of Medicine, Department of Neuropsychiatry, Motofuji-cho 1, Tokyo, Japan.

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