From unborn to born to toddler, a baby’s brain goes through amazing developments in the first years of life. These developments come about due to a subtle dance between the baby’s genes and influences from the surrounding environment which encompass both what happens in the womb and what happens after birth, in the baby’s home and caregiver setting. Many parents and teachers appreciate how important it is to nurture healthy brain development, but even greater awareness is needed if more children are to reach their full potential.
In the realm of public policy, numerous programs-Show-Me Healthy Babies, Parents as Teachers, First Steps-have been established to provide assistance to the developing child, both before and after birth. Future MCC Updates will examine some of these programs, including their effectiveness and funding levels. However, before delving into these programs, it may be helpful to review early human development, especially the early development of the brain, and to understand what is at stake if healthy brain development does not take place in these early years.
In the womb a tiny neural tube is formed and fully closed normally by 27 days post conception. This tube then begins its transformation into the brain and spinal cord. By the end of the embryonic period, which is the end of eighth week post conception, the basic structures of brain and central nervous system are in place. The production of information processing cells (neurons) begins at 42 days post conception. In the first five months of the pregnancy an unborn baby will produce about 100 billion neurons, more than will be produced after birth.
Synapses that connect neurons and allow them to communicate begin to form five weeks after conception. Soon after that the unborn child begins moving limbs and fingers, as well as yawning, thumb sucking, and swallowing. The second trimester sees the development of basic reflexes such as coordinated breathing. Finally, before birth, the cerebral cortex, the outer layer of the brain that directs thinking and voluntary actions, begins to develop.
But after birth the baby’s brain is still not fully formed. The cerebral cortex continues to develop and there is an explosion of synapses created to improve information processing among the various parts of the brain. At birth the baby’s brain is only about a quarter of the size of the adult brain and it works about 16 times slower than the adult brain. A substance called myelin develops to coat and insulate the brain connectors (axons). Myelination is especially rapid in the first two years of life and it helps to speed up the brain’s ability to process information.
All of this development is essential for the child if she is to have the opportunity to acquire skills, such as talking and understanding others and, later, reading, writing and computation. Want to learn more? The National Center for Infants, Toddlers and Families has a website-Zero to Three-that offers a brief layman’s summary of early brain development. The more ambitious may wish to watch a lecture by the developmental congnitive neuroscientist Joan Stiles, who teaches at the University of California-San Diego and is the founder of the Center for Human Development.