Understanding the Brain: In the Beginning
When I was in University, the understanding at the time was that a baby was born Tabula Rasa. In other words, a baby’s brain was a ‘blank slate’. Fetal growth patterns and experiences were largely ignored. It was only a baby’s experience from birth-forward that was thought to shape the child’s mind.
Since brain growth was thought to be similar to a scaffold, the second layer was built upon the foundation of the first layer. The third layer was built upon the second layer and so on. It was understood that opportunities for brain growth became limited after the early years unless the base had already been created upon which to layer new information. As such, we were encouraged to pack as much information and experiences into our child’s first 5 years of life to maintain maximum opportunities for brain growth.
With the explosion of research in brain science we now have a more accurate understanding of brain growth and development. It isn’t quite as cut and dry as we used to think. The brain is so much more complex then we first imagined. Do you remember when they used to tell us that we only use about 5% of our brain? That is such a ridiculous statement now.
Let’s examine the beginning of brain life. The brainstem, an organ we share with many reptiles, animals and fish, actually begins to emerge in the first few weeks after conception. In fact, most of the other early structural features of the brain begin to appear during the first 8 weeks after fertilization. They of course, continue to grow and develop throughout the pregnancy.
At approximately seven weeks after conception, the first neurons (nerve cells) and synapses (bridges between the nerve cells) begin to develop in the spinal cord. There is no actual brain yet, just a brainstem at the top of our spine. These early neural connections allow the fetus to make its first tiny movements. Although Mom cannot yet feel them, these movements provide the fetus with neural stimuli and sensory input that promote the development of more complex brain functions.
Early in the second trimester, the cerebral cortex begins to emerge and grow and synapse function in this area begins. Myelin (think of the teflon coating on your frying pan) begins to appear on the axons (arms of each nerve cell). This process – called myelination – allows for faster, smoother processing of information between cells. Our neural network is already leaving behind the bumpy country pathways it first travelled and is building a super-fast expressway for information transport.
In the third trimester the cerebral cortex matures enough to assume some of the duties formerly carried out by our primitive brainstem. These duties included fetal breathing, heart rate and responses to external events. The cerebral cortex also assumes responsibility for the baby’s intelligence, personality features, motor functions, planning abilities and sensory processing. That is a lot of responsibility for a brain that hasn’t yet left the womb.
The newborn’s brain continues to develop at an amazing rate after birth and throughout the baby’s first year. The cerebellum or the ‘hind brain’ triples in size. Although this part of the brain accounts for only ten percent of the brain’s total volume, it houses approximately fifty percent of the brain’s neurons. This neural development is thought to be related to the rapid acquisition of motor skills that occurs in infants during their first year. The cerebellum helps us to walk upright, as well as maintain our posture, balance and fine motor movement.
As the visual areas of the cerebral cortex grow, the infant’s initially dim and limited view of their world develops into binocular and full-colour vision. An infant’s power of recognition improves dramatically at about the 3 month mark. This coincides with significant growth in the hippocampus, the structure related to recognition memory.
Language circuits in the frontal and temporal lobes also start to develop and are strongly influenced by the amount of language the infant hears in their first year. The more language they hear, the more brain circuitry develops. Children will first understand language and then be able to express and repeat a few words.
In the child’s second year, the most dramatic changes involve the brain’s language areas. These areas have developed more synapses and become interconnected. These changes relate to the sudden spike in the child’s verbal abilities – sometimes called the vocabulary explosion. Frequently, a child’s vocabulary will quadruple between their first and second birthday.
Research indicates that there is also a major increase in the rate of myelination (remember the teflon-like coating on our nerve arms) which helps the brain perform more complex tasks. More complicated abilities like self-awareness develop in the second year. A child becomes more aware of his own emotions and intentions. A youngster can also recognize the reflection in the mirror as his own at this stage.
During the third year, brain connectivity or synaptic density in the prefrontal cortex reaches its peak. This region also continues to create and strengthen the neural networks with other brain components. As a result, complex cognitive abilities improve and solidify.
By age 3, much of the groundwork for a healthy brain has been established. The four and five year old child begins to strengthen and use their neural pathways to develop greater independence, self-control, and to explore creative pursuits. They are content to play independently with their toys, are open to try new things, and when they get frustrated, are better able to express their emotions.
Early brain development starts in the womb. It is essential that a Mother care for her body during these nine months. Nutritious food, exercise, sleep and a safe overall environment are all essential for the child’s brain development.
We know now that early experiences have a huge potential to affect brain development. The early years provide a small window of opportunity for parents, caregivers, and communities to enhance a child’s growth. A child’s positive early experiences have an enormous impact on the child’s potential for achievement, success, and happiness in their later years.