Chapter Overview

The physical development of an individual from zygote (fertilized egg) to mature adult is one of the most awe-inspiring and wondrous processes in all of nature. This is especially true for the development of the human brain, with its enormously complex organization, and for the development of the complex behaviors that are the fruit of its biological development. Understanding the fascinating process of brain development illuminates our understanding of the mature brain because knowing how something has come into being illuminates our understanding of its current state. We will see that this is true from a number of perspectives, from neuroanatomy (Why do the lateral ventricles have such peculiar shapes?) to functional neuroanatomy (What are the neurobiological correlates of developing visual acuity in the infant?).

The process of development does not always run smoothly. An understanding of disorders of development, important for the understanding and treatment of people with developmental disorders, can also shed light on the process of normal development. We turn now to a discussion of these domains.