Effects of early and late transection of the corpus callosum in children: a study of tactile and tactuomotor transfer and integration

Five children, aged 6 to 16 years, were tested for unilateral discrimination and interhemispheric transfer of tactile information as well as tactuomotor learning at various intervals before and after therapeutic callosotomy. Comparison of preoperative and postoperative capacities revealed that younger children are considerably less affected by the interruption of callosal transmission than older children. Bilateral organization of speech and participation of the anterior commissure can largely be excluded as possible compensatory mechanisms. The most plausible explanation for the excellent preservation of interhemispheric integration of tactile functions in the younger patients appears to be continued reliance on ipsilateral pathways. The relatively greater deficits observed in the older children, on the other hand, suggest that sensorimotor functions come to depend more extensively on contralateral pathways as the corpus callosum reaches functional maturity.