THE EFFECTS OF EPILEPTIC CORTICAL ACTIVITY ON THE DEVELOPMENT OF CALLOSAL PROJECTIONS

The effect of epileptic neural activity on the postnatal development o f the corpus callosum was studied. Epileptiform activity was induced i n the visual cortex of postnatal rabbits by continuous infusion of pen icillin. Callosal projections of the occipital cortex were studied in rabbits aged at least 4 weeks. In these penicillin-exposed rabbits, th e visual callosal projections extended through most of area 17 in a pr ojection pattern characteristic of neonatal rabbits, rather than being restricted to a narrow callosal zone at the lateral border of area 17 , as they usually are by this age. The results indicate that epileptic cortical activity stabilizes immature callosal projections which are normally eliminated during development. The maintenance of such immatu re and non-specific projections in the mature CNS may interfere with n ormal cortical functions and could underlie the cognitive deficits whi ch have been observed following childhood epilepsy.