The role of the corpus callosum in bilateral interhemispheric synchrony of spike and wave discharge in feline generalized penicillin epilepsy.

In this study on interhemispheric synchrony of spike and wave discharges in feline generalized penicillin epilepsy, four groups of cats were treated in the following manner: Group A underwent complete section of the corpus callosum and anterior commissure; group B underwent division of the massa intermedia alone; group C underwent partial section of the corpus callosum; and in group D, a slab of the cortex on one side, comprising the middle parts of the lateral and suprasylvian gyri, was severed from all its subcortical inputs, without disturbing its connections with the opposite hemisphere through the corpus callosum. Two weeks after surgery or later the cats received an i.m. injection of penicillin. Bilateral synchrony of the epileptic discharges was abolished in group A, but not in group B. In group C, bilateral synchrony of the epileptic bursts was impaired, but not abolished. In group D, epileptic bursts synchronous with those occurring in the intact hemisphere continued to occur in the slab, but at lower amplitude. It is concluded that the corpus callosum is the main, if not the exclusive, pathway ensuring bilateral synchrony of the epileptic discharges of feline generalized penicillin epilepsy.