EXPERIMENTALLY-INDUCED LAMINAR NECROSIS, STATUS VERRUCOSUS, FOCAL CORTICAL DYSPLASIA REMINISCENT OF MICROGYRIA, AND PORENCEPHALY IN THE RAT

Different types of cortical malformation were produced, following foca l cortical freezing, electrocoagulation, focal cortical aspiration or gentle brushing of uncovered meninges, in newborn or 1- to 3-day-old r ats. Malformations included laminar necrosis of the cerebral cortex, s tatus verrucosus, focal cortical dysplasia reminiscent of microgyria, and porencephaly. Similar procedures from postnatal day 4 onwards, at a time when a reactive astrogliosis is possible, produced cavitating i nfarcts and tissue scars. Cytoarchitectonic studies revealed an abnorm al distribution of different types of pyramidal and nonpyramidal neuro ns in these malformations. These indicated three subtypes of focal cor tical dysplasia, which probably depend on different pathogenic mechani sms. Autoradiographic studies with [H-3] methylthymidine showed normal positioning of late-generated neuroblasts in the cerebral cortex, thu s suggesting preserved migration. The present experimentally induced c ortical malformations are useful models of similar cortical abnormalit ies in humans.