Creating Connections in the Developing Brain
Mechanisms Regulating Corpus Callosum Development

The corpus callosum is the largest fibre tract in the human brain and subserves many of the brain’s higher-order functions. Disconnection syndromes resulting from surgical ablation, developmental absence (agenesis of the corpus callosum), disease, or injury of the corpus callosum can have profound consequences on cognition. Callosal development involves an intricate series of sequential and concurrent processes, including telencephalic induction, midline tissue patterning, production and specification of callosal neurons. In addition, axon extension and long-range axonal guidance from one hemisphere to the other are required for functional circuit formation in the contralateral hemisphere. Genetic or traumatic disruption to any part of this sequence is pathogenic. Understanding the key processes involved in callosal development is the first step in providing both better neuropsychological outcomes and improved diagnostic and prognostic tools for congenital disconnection syndromes in the future.

Table of Contents

Introduction
Formation of the Telencephalic Hemispheres
Midline Tissue Patterning: Preparing the Callosal Substrate
Specification of Callosal Projection Neurons within the Neocortex and Cingulate Cortex
Establishing the Callosal Tract
Navigating the Midline: Growth of the Corpus Callosum Across the Interhemispheric Midline
Contralateral Targeting of Callosal Axons: The Role of Neuronal Activity
Conclusion
References

About the Author(s)

Linda Richards, Queensland Brain Institute, University of Queensland, Australia

Ilan Gobius, Queensland Brain Institute, University of Queensland, Australia