Brain development and generation of brain pathologies

The timing of brain development is genetically programmed and can be profoundly altered by a number of abnormal genes that control proliferation, differentiation, migration, synapse formation, and elimination of cells and synapses. With advances in genetic techniques both the gene and gene product responsible for brain malformation are being identified which will permit a better understanding of the pathophysiology of brain malformations. In addition to genetic abnormalities, brain development can be influenced by a variety of acquired disorders. The type of brain abnormality is highly dependent on the stage of brain development during which the insult occurs. While our understanding of experience- or activity-dependent processes on brain development is limited, it is now clear that this activity can significantly alter the timing of a number of maturational events including receptor maturation and neurogenesis. The future challenge will be both to understand the biological basis of these processes and to use this information to enhance brain development.