Suppressive effect of callosotomy on epileptic seizures is due to the blockade of enhancement of cortical reactivity by transcallosal volleys.

The present work demonstrates that the cortical reactivity of the rat, monitored by thalamocortical responses, can be enhanced by repetitive transcallosal volleys (5-20 Hz). This effect can be completely inhibited by callosotomy. We believe that the interhemispheric epileptogenesis and the suppressive effect of callosotomy for intractable epilepsy can be explained by this facilitatory effect of the corpus callosum on the cerebral cortex. Copyright 2002 Elsevier Science B.V.