A baby's brain is a work in progress. The first brain cells begin to form by the fourth week of fetal life. By 24 weeks, the brain has nearly all its nerve cells, or neurons, and the process of setting up circuits or connections has begun. By the time a baby is born, the neurons are ready to act as mission control, sending messages throughout the brain and the rest of the body. Over the first months and years of life, a baby's brain continues to actively work to establish the basic connections that link various parts of the brain and nervous system into a coordinated whole.
Some scientists compare the development of a baby's brain to building a telephone system. Genes determine the basic wiring plan, but at birth, many connections between phones have yet to be made. During the first few years of life, the most active connections (think of them as the wires between phones getting the most calls) become the strongest (think of this as an application of the "use it or lose it" theory). While making connections is a continuous process throughout a person's lifetime, it is in the earliest years that things are really humming. A baby's experiences (making and using those connections) drive the process of brain and nervous system development. Thus, experiences after birth are as important as a baby's condition at birth.
Because the brains of premature infants have had less time to grow, these infants have fewer brain cells at birth. This makes it harder for preemies to process the many sources of stimulationsounds, sights, touch, and movementin their environment. They are often less able to coordinate their heart rate and breathing patterns. These tiny babies use much of their energy trying to handle a too-bright and too-loud world, while full-term babies have more strength and control to block out some of this stimulation.
Timing of experience is another important issue for early brain development. The brain is especially open to learning certain skills at certain agescalled critical periodsand not at other times. Likewise, illness or injury that occurs at a particular stage of early brain development will threaten functions controlled by areas of the brain that are just developing at that stage. For example, when the fragile blood vessels in the brains of very premature infants leak or close off, children are at risk for developing a form of cerebral palsy that primarily affects the legs.
During a baby's first two to three years, new cells will grow to enable his brain to function in a more organized and efficient manner. For infants born prematurely, developmental goals are adjusted by the number of weeks of prematurity, until those weeks become insignificant in comparison to the age of the child, usually at about two to three years. The growth of new cells helps babies' brains:
Developmental intervention during early childhood, when the brain is actively organizing its structures and functions, can help infants overcome or adapt to many of the physical and cognitive challenges that may result from preterm birth and hospitalization. In effect, many preemies have the capacity to catch up, partially or completely.
Parents and other caring adults can further this development. Positive, loving relationships help children learn how to control emotions and handle stress. The opposite is true too: Violence, threats, parental depression, emotional distance, or insensitivity can handicap a child's emerging brain and nervous system. This kind of negative treatment is likely to cause a child to be constantly on guard, nervous, overly sensitive, apathetic, or aggressive and to develop higher heart rate and blood pressure, even at rest. When care is consistently affectionate, responsive, and flexible, a child is more likely to become cooperative, happy, and achievement-oriented. He is also likely to have greater self-esteem and problem-solving skills.
Premature infants are as likely as other children to demonstrate a wide range of individual differences in personality, health, behavior, and development. From the beginning, parents, friends, and extended family play a vital role in sensing and supporting a child's unique needs at each stage of development. Loving adults will help their children discover and trust their strengths.
Children continue to develop throughout childhood. Their experiences at home, at school, among friends, and in the community continue to affect their progress. The science of brain development teaches that:
For full-term and preterm babies, consistent, loving care is powerful medicine.