Influence of learning to read and write on the morphology of the corpus callosum

Variations in the individual anatomy of the corpus callosum have been repor ted in several conditions. There seem to be genetic influencing factors, bu t it is impossible to rule out some environmental ones. This study focuses on the question of the environmental factors, using formal learning to read and,write as the main difference in the groups to be compared. Based on ma gnetic resonance imaging sagital images, the contour of the corpus callosum (CC) of 41 carefully selected women (18 illiterate and 23 literate) was di gitized. The comparison between the two groups showed a small difference in the region of the CC where parietal fibres are thought to cross. This regi on is thinner in illiterate subjects. As illiteracy in this group is the re sult of social constraints, and the two groups that were compared are well matched for other cultural and pragmatic aspects than literacy the results are interpreted as showing the possible influence of formal learning to rea d and write, on the biological development of the brain. Eur J Neurol 6:23- 28 (C) 1999 Lippincott Williams & Wilkins.