Regional size reduction in the human corpus callosum following pre- and perinatal brain injury

This morphometric study examined two aspects of corpus callosum development : pediatric cortico-callosal topography and developmental neuroplasticity s ubsequent to perinatal brain injury. In vivo magnetic resonance imaging was used to quantify the total midsagittal cross-sectional area and five anter ioposterior subregions of the callosum in 10 children with focal lesions an d 86 healthy volunteer control subjects. Nine of the ten children with earl y injury showed a reduction in the total area of the callosum relative to m atched controls. The area of the total callosum cross-section was inversely proportional to the size of lesion. All patients displayed region-specific size reduction. This regional thinning bore a topographical relationship t o the lesion sites. Reduction in anterior subregions 1, 2 and 3 was respect ively associated with lesions in the anterior inferior frontal area, the mi ddle and superior frontal region, and the precentral area. Attenuation of s ubregion 4 corresponded to anterior parietal lesions, and thinning of subre gion 5 occurred with posterior parietal injury. This cortical-callosal patt ern coincides with adult and nonhuman primate mappings. Callosal thinning d espite the early onset of the lesions suggests limits to developmental neur oplasticity.