In babies, crucial neural connections happen before age three

Though we weren’t aware of it, our brain was growing explosively in the first few years of our lives. From birth to age three, babies gain more than a million neural connections every second. This crucial period of brain formation will affect how a person learns, communicates and behaves for the rest of their lives. 

The brain is made up of neurons, specialized cells that send messages to the rest of the body. Every new experience and memory creates connections between neurons, or synapses. These connections enable basic brain functions. 

Like the foundation of a house, stronger connections early in life lead to more functional brains. During early formation, the brain forms more connections than it needs, and with time and experience, it prunes back unneeded connections. In the first four years of life, a baby’s head grows 80 percent of its adult size to accommodate the growth. 

Although our genes dictate how brain connections form, experience activates the connection. For example, the circuits that enable language and vision can only be properly formed when a baby hears and sees stimulating action. 

Therefore, babies need lots of interaction in order to learn. When a baby gurgles, cries or waves a hand, it’s important for caregivers to respond. This interaction, known as “serve and return,” strengthens the neural connections that dictate communication and social skills. 

The back and forth volley of baby talk, hugs and eye contact builds the baby’s brain architecture. That architecture provides a foundation for neural connectivity and higher brain function later in life. 

If babies don’t engage or interact with others, they don’t develop strong neural connections. Although the brain can adapt throughout life, as we age it becomes more difficult for our brains to change. That’s why it’s important to foster the brain during the sensitive early years of life. 

A baby’s brain in the first three months focuses on neural connections that enable seeing and hearing. After mastering that, the brain focuses more on language and speech production. Around the one year mark, the brain turns to higher cognitive functions. But higher-level brain function depends on the quality of lower-level circuits formed soon after birth. Babies need stimulating and responsive interactions to develop those lower-level circuits. 

So, when you see a baby waving at you, wave back! You’re doing the brain a favor.


—Frank Graff 

Frank Graff is a producer/reporter with UNC-TV, focusing on Sci Tech Now North Carolina, a weekly science series that airs Tuesdays on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!


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