Neonatal hemidecortication or frontal cortex ablation produces similar behavioral sparing but opposite effects on morphogenesis of remaining cortex.
Rats with complete removal of the neocortex of one hemisphere (hemidecorticate) or of the cortex anterior to bregma in both hemispheres (frontal cortex) in adulthood were compared behaviorally and neuroanatomically with rats with similar removals at 7 days of age. Neonatal ablation of the frontal cortex produced partial sparing of performance on the Morris water task and reduced the thickness of the remaining neocortex. Neonatal hemidecortication produced similar sparing of function on the water task but increased the thickness of the contralateral neocortex. These results imply that behavioral sparing following neonatal cortical lesions is independent of the gross morphogenesis of the remaining neocortex.