ABSTRACT
The complex structure of the brain of human begins with evolution. The events that occur during the development of brain are the proliferation of the total complement of neurons in the brain and the migration of these neurons to specific sites throughout the central nervous system (CNS). In addition, the series of organizational events that result in the intricate circuitry characteristic of the human brain, and the ensheathment of this circuit of neurons with the myelin sheath occur. These events start after the end of the first month of the gestation period and continue into adulthood. There are numerous prenatal and perinatal insults during the critical developmental events that may be responsible for errors in the growth of the brain. Several genetic perturbations may also occur during the brain’s development. Several (genetic) diseases occur due to alterations in the usual developmental process of the brain. Disorders related to the proliferation of neurons such as microcephaly, macrocephaly, unilateral macrocephaly, growth-associated disturbances, focal cortical dysplasia and related disorders, chromosomal disorders, and neurocutaneous syndromes have the most important influence on the functions of the CNS. This chapter provides an outline of the important aspects involved in the normal proliferation of neurons. The chapter also discusses the disorders/diseases interrelated with the altered development of brain.
