Brain power

Your baby’s brain development is a vital process. Learn how it goes from zero to 100 billion neurons in just nine months

THE HUMAN BRAIN is a wonder of complexity: while awake, our brains generate enough energy to power a light bulb and are capable of processing information at a rate of 430kph.

It’s no wonder the brain is one of the very first organs to develop in the foetus – after all, it’s the super computer that controls and coordinates every thought and action, for the rest of your life.

IN THE BEGINNING

A few weeks into your pregnancy, your baby’s brain is already growing at an astonishing rate. At the peak of its development, an embryo’s brain grows by 250 000 neurons a minute. Neurons are the specialised nerve cells that are found in our nervous system, and in our brains, they form what is also called grey matter. Although you won’t see much more than a lump of cells during your ultrasounds in the first trimester, proportionally, the embryo’s head is huge in comparison to the rest of the developing body.

The brain and spinal cord begin as a simple neural tube. In week four, the brain separates into three sections – the fore brain, middle brain and hind brain. Then in week six, it further divides into the left and right hemispheres. Scientists claim to already be able to pick up some wave activity by this stage.

You might not even know you’re pregnant while this rapid brain development is going on. This is why doctors advise that you should be taking folic acid – a B vitamin that helps prevent neural tube defects – if you’re trying to fall pregnant. Stick with the folic acide throughout your pregnancy.

COMMON SENSE

As the brain of the foetus becomes more intricate, it’s thought that the first of the five senses to develop is touch. As early as eight weeks into your pregnancy, your baby can feel touch on her lips and cheeks. This extends to the rest of her body by 14 weeks. What’s interesting is that while the brain controls the sense of touch, brain tissue itself has no feeling. Tastebuds begin to develop at 12 weeks, and by 13 weeks the chemoreceptors for smelling are formed and olfactory nerves have connected to the brain. Hearing is fine-tuned at 22 to 24 weeks, when your unborn baby can distinguish mom’s voice.

Vision is the last sense to develop, with baby opening her eyes for the first time from 26 weeks. From this point onward, the brain is regulating all of your baby’s body functions, including breathing.

BRAIN WRINKLES

Up until the sixth month of pregnancy, the surface of your baby’s brain is still smooth. Now the cerebral cortex, which is the top layer of the brain, starts to develop convolutions (imagine what a walnut looks like without its shell). It has been thought that in humans, having more “folds” in specific areas of the brain is an indicator of aboveaverage intelligence, but science is yet to prove this theory conclusively.

The cerebral cortex folds to fit as much of this densely packed grey matter into the tight confines of our skull. More than two-thirds of the brain is found in the grooves of the cortical folds.

READY AT BIRTH

By the last trimester, your baby’s brain continues on its steep developmental curve, growing larger and establishing more connections. At birth, a newborn’s brain has an amazing 100 billion neurons. Why so many? It’s because Mother Nature gives you double what you’ll need as an adult, just in case. According to at least one study, by the time you reach sexual maturity, you’ll have shed around 41 percent of the neurons you were born with. Still, 100 billion neurons do not mean that a baby’s brain is lightning fast – in fact, it’s relatively slow. That’s because it is the synapses or “sparks” between these neurons that determine how quickly information leaps between brain cells. At birth, a baby has around

2 500 synapses per neuron; these increase to up to 15 000 by the time the child is three years old.

GROWTH SPURT

It’s not just synapses that increase exponentially in the early years. Despite the process of synaptic pruning, where the brain trims back on the neurons that it’s not using, your newborn’s brain will continue to enlarge rapidly, growing to about three times its size in the first year. By the time your child is five years old, her brain will have reached 95 percent of its adult size already. Again, make sure you have a good intake of folic acid – to help your baby’s brain along.