At birth a full term baby’s brain weighs about 400 grams and has around 100 billion brain cells.  

The brain develops in a particular order; the brain stem is the least complex and develops first and is fairly mature at birth. The brain stem controls basic functions such as heart rate, temperature, sucking and digestion. The limbic system matures next, which is responsible for sleep, appetite, emotions and the ability to form attachment.  

By the time they are 3 years of age the brain weighs 1100 grams! The increase is size and weight can be attributed to the connections that are forming in the brain and good nutrition.  

New connections

Every experience your baby has is new and is forming a new connection in the brain. It is exhausting which is why your new baby needs so much sleep. When babies sleep they rehearse their new learnt skills. 

All those nappy changes and feeds provide a wonderful opportunity to form connections in the brain. Much of what a baby needs for brain development occurs within relationships with other people.  

  • Talk to your baby while you feed.  
  • Chat and ask questions when you change a nappy.  
  • Talk about what you are doing- while it might feel awkward at first you will get better at it and enjoy the response you get from your baby. 

REM sleep and brain development

Sleep is important for healthy brain development and creativity. Sleep helps the brain to form patterns and lays down memories from and about experiences. Sleep improves motor and perceptual skills. 

Over the last ten years researchers have tried to provide insight about the developmental functions of sleep. During the late foetal stage and early weeks after birth, there is a high percentage of REM sleep. This is a critical period in brain growth, function and maturing. During REM sleep, experiences and activities are consolidated in the brain. 

Circadian rhythms are those natural signals in our bodies that tell us when to eat and sleep. Circadian rhythms are not developed in babies until they are four to six months old. As a result, babies can become hungry or tired at any time of the day or night. With regular and repeated cues from an adult, babies learn to understand the experience and begin to form a feed, play, sleep pattern. 

Babies encode memories during REM sleep. Their memories are the ones formed through the senses. They include the sound of their parents’ voice and smell, the sounds of home, the warm sensation of being cuddled and repetitive experiences of being responded to when they cry. 

Researchers suggest that by day ten, your baby can remember the way you smell. At one month they can remember when they are fed and come to expect to be fed at that time. 

What can parents do?

  • Tune in to baby’s tired signs to avoid overstimulation and help them sleep. 
  • Help to resettle to sleep if they wake after a short sleep cycle. 
  • Warm and responsive parenting helps babies feel safe and calm. This helps to form positive memories through their senses and daily experiences while they sleep. 
  • Babies also learn routine by regular cues from parents in the way they are settled to sleep. Pat, rock and stroke your baby to calm them. Stop calming them when they are quiet but still awake so they learn to fall asleep during this calm state by themselves. 
  • Keep the light dim during sleep times as the sleep hormone melatonin level is dependent on the amount of light. Keep household noises normal as babies become familiar with these sounds and it helps them to feel secure. 

Want to know more?

The Royal Children’s Hospital Melbourne – Brain Builder